Housewrap question: Tyvec vs. tarpaper
George Milner
I have 2 questions.
We are involved in making decisions on new house construction. One of the
choices is thermo-ply or OSB for the exterior walls. There is no cost
difference. We will probably choose OSB. If we do that, we then choose
tarpaper or Tyvec. However, Tyvec comes with a $1700 premium. Tarpaper cost
is built in.
1. I don't know whether the added benefits of Tyvec are worth it. We plan on
staying in the home for 20+ years, but the site manager feels that the Tyvec
is overkill and not needed -- that the tarpaper wrap achieves nearly the
same results.
2. On the other hand, every builder I speak with says to go for plywood
instead of OSB for the *roof* so I think that we'll probably do that and
pay the premium.
Any thoughts are appreciated.
Thanks.
George Milner
David J. McBride
George Milner wrote:
> We are involved in making decisions on new house construction. One of the
> choices is thermo-ply or OSB for the exterior walls. There is no cost
> difference. We will probably choose OSB. If we do that, we then choose
> tarpaper or Tyvec. However, Tyvec comes with a $1700 premium. Tarpaper cost
> is built in.
You do not say what region of the country you are in so I will give you
a perspective for a warm, humid, coastal climate. I often see Tyvec
going up in this area now; I assume it is a high profit item because I
don't believe that the local climate warrants such a product. Along the
Gulf Coast the primary objective relative to air infiltration is to move
moisture *out* of the structure, not trap it in (I know, Tyvec is
supposed to breathe). Along those lines I believe the regimen calls for
no more than asphalt impregnated sheathing with half inch CDX plywood at
all corners. Felt may be laid over the exterior sheathing depending
upon the siding or veneer to be applied and perhaps, even, furring
strips over the felt. I am distressed also to see the foil faced
styrofoam type sheathing being applied; to my way of thinking, it is a
surefire moisture trap. The one and two hundred year old houses along
the coast reached their age primarily because their wall cavities have
been void of any moisture trapping materials. That is to say that they
breathe extremely well.
> 2. On the other hand, every builder I speak with says to go for plywood
> instead of OSB for the *roof* so I think that we'll probably do that and
> pay the premium.
Absolutely. OSB has been outlawed in Florida (thank you, Andrew) at
least as a roof sheathing material. I am all for CDX roof sheathing,
5/8" if it's in your budget. If you are in a warm climate where your
roof will be exposed to continuous sunlight (as in no shade) there is
available a foil faced plywood product called CoolPly or KoolPly. The
foil face goes down and acts as a radiant barrier reducing the amount of
attic insulation necessary to achieve the same R-values. Down here,
R-30 is the accepted standard for attic insulation; a radiant barrier
reduces that reduces that requirement to R-19. If the CoolPly is not an
option there are radiant barrier films available that can be stapled to
the bottom of the rafters that perform equally as well.
--
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Dj...@worldnet.att.net
David J. McBride
Houston, Texas
danh...@millcomm.com
In <6dujii$8l4$1...@winter.news.erols.com>, "George Milner" <george...@erols.com> writes:
>I have 2 questions.
>
>We are involved in making decisions on new house construction. One of the
>choices is thermo-ply or OSB for the exterior walls. There is no cost
>difference. We will probably choose OSB. If we do that, we then choose
>tarpaper or Tyvec. However, Tyvec comes with a $1700 premium. Tarpaper cost
>is built in.
>
>staying in the home for 20+ years, but the site manager feels that the Tyvec
>is overkill and not needed -- that the tarpaper wrap achieves nearly the
>same results.
>
>instead of OSB for the *roof* so I think that we'll probably do that and
>pay the premium.
>
You don't say how big the house is or where you live. In the Frozen North
you definitely want the Tyvek air infiltration barrier. Farther south it
probably isn't worthwhile. In any event $1700 sounds awfully high for
Tyvek unless this is a mansion of some sort. The stuff is no harder to
install than tarpaper (probably easier) and the extra materials cost would
run less than $500 for a typical home.
Dan Hicks
Hey!! My advice is free -- take it for what it's worth!
http://www.millcomm.com/~danhicks
Roy Smith
DjMcB, at, worldnet, dot, att, dot, net wrote:
> OSB has been outlawed in Florida (thank you, Andrew) at least as a roof
> sheathing material. I am all for CDX roof sheathing, 5/8" if it's in
> your budget.
We're just getting bids back on a major renovation job. One of the
contractors put in his bid that all sheathing and sub-floring would be
Oriented Strand Board. I assume that's what you mean by OSB.
Exactly what is OSB? I gather it's not as good as plywood. Is it
adequate for subflooring, or should we demand real plywood?
Jim Ilkay
If you live in a cold, windy climate, you should consider Tyvek. Otherwise,
it's not necessary. I'm in the central Texas market and I'm beginning to see
many houses wrapped in Tyvek for no reason that I can understand (other than
the fact that it's a high profit item). These same houses have cheap
aluminum windows in most cases so go figure.
Jim Ilkay
bui...@texas.net
George Milner wrote in message <6dujii$8l4$1...@winter.news.erols.com>...
>I have 2 questions.
>
>We are involved in making decisions on new house construction. One of the
>choices is thermo-ply or OSB for the exterior walls. There is no cost
>difference. We will probably choose OSB. If we do that, we then choose
>tarpaper or Tyvec. However, Tyvec comes with a $1700 premium. Tarpaper cost
>is built in.
>
>1. I don't know whether the added benefits of Tyvec are worth it. We plan
on
>staying in the home for 20+ years, but the site manager feels that the
Tyvec
>is overkill and not needed -- that the tarpaper wrap achieves nearly the
>same results.
>
>2. On the other hand, every builder I speak with says to go for plywood
>instead of OSB for the *roof* so I think that we'll probably do that and
>pay the premium.
>
>Any thoughts are appreciated.
>
>
>
>Thanks.
>
>George Milner
>
>
>
>
GMB346
>
>We are involved in making decisions on new house construction. One of the
>choices is thermo-ply or OSB for the exterior walls. There is no cost
>difference. We will probably choose OSB. If we do that, we then choose
>tarpaper or Tyvec. However, Tyvec comes with a $1700 premium. Tarpaper cost
>is built in.
>
>1. I don't know whether the added benefits of Tyvec are worth it. We plan on
>staying in the home for 20+ years, but the site manager feels that the Tyvec
>is overkill and not needed -- that the tarpaper wrap achieves nearly the
>same results.
>
>
Hello:
A few weeks ago there was major stuff on Tyvek vs building paper. The
conclusion was in favor of the building paper. Some of the more intelligent
responses discussed the huge payback time for the supposedly superior
performance of Tyvek. I tend to agree. You should probably spend that $1700
somewhere else..say a window or glass quality upgrade or whatever. The problem
with a Tyvek house, is that most builders don't pay any attention to sealing
the places where infiltration is the greatest. A lot of infiltration canbe
stopped by proper use of sealants and tape. Cheap materials but high time
consuming labor. I would go for the building paper instead of Tyvek.
Gary
GMB346
>
>2. On the other hand, every builder I speak with says to go for plywood
>instead of OSB for the *roof* so I think that we'll probably do that and
>pay the premium.
>
>
Hello:
I would be interested in why the use of plywood for the roof instead of OSB
board. Both are APA-rated (American Plywood Association) for that use? What
advantage do they cite to convince you that it is good enough for wall
sheathing, but not good enough for roof sheathing?
Gary
Chappy
I just priced some tyvec last week. It comes in 9'wide by 100' long and the
price is $116.60 tax included. Which gives it an average price of around 13
cents per square foot. So, for $1700, that would buy 14 rolls of the stuff.
Whenever we use it, we usually get by with 2, occasionally 3 rolls of it.
So either you have an incredibly huge house, or someone has put a pretty
high premium on the labor to put in on. It goes on quick and easy.
George Milner wrote in message <6dujii$8l4$1...@winter.news.erols.com>...
>I have 2 questions.
>
>We are involved in making decisions on new house construction. One of the
>choices is thermo-ply or OSB for the exterior walls. There is no cost
>difference. We will probably choose OSB. If we do that, we then choose
>tarpaper or Tyvec. However, Tyvec comes with a $1700 premium. Tarpaper cost
>is built in.
>
>1. I don't know whether the added benefits of Tyvec are worth it. We plan
on
>staying in the home for 20+ years, but the site manager feels that the
Tyvec
>is overkill and not needed -- that the tarpaper wrap achieves nearly the
>same results.
>
>2. On the other hand, every builder I speak with says to go for plywood
>instead of OSB for the *roof* so I think that we'll probably do that and
>pay the premium.
>
Randy Hubbard
FWIW,
The *installed price* of TYVEK varies all over the map depending on what a
builder feels he can get for it... It is NOT difficult to install, and can
actually be Properly installed with a little common sense and by reading the
instructions. On new 2000 SF houses in my area of the mid-west the going rate is
$600-$900. which allows very adequate labor cost for installation, though it's
rarely installed properly...
Randy
rto...@removethis.oanet.com
OSB is made from wood chips rather than from plies as in plywood.
They are coated with a powder adhesive and then pressed under very
high pressure and high temperature - just as is plywood - until the
thermosetting adhesive sets.
OSB is stiffer than plywood, that is, it has a higher mudulus of
elasticity. That can be an advantage in roofs and floors. Floors
should be 3/4 inch minimum and tongue and groove. Make sure all
sheets come from the same batch as there is sometimes a small width
difference between batches which makes lining up sheets difficult.
In my opinion, for what it is worth, OSB is just as good as plywood
for sheathing, roofing and sub-flooring if the proper thickness is
used. And it is nearly always cheaper than plywood. Roofing should
not be less than 1/2 inch for 24" span across trusses. Don't let a
builder talk you into 3/8", it may be legal but it is too flexible for
really long life.
George Milner
I would like to thank everybody for the quick responses to my questions. I
received over 25 emails, some that showed up in the NG.
Here is a summary of what was said:
The majority pointed out that I didn't mention where the house would be
built. Sorry. We will be building in Bucks County, PA (about 1 hour north of
Philadelphia).
That's relevant because the decision on Tyvek is made easier if the climate
gets cold and windy. Most respondents felt that it would be useful in that
environment -- with two significant additional points.
1. Install it properly -- and get that in writing.
2. Also spend time caulking and otherwise sealing where possible.
Of those that didn't feel Tyvek should be used, half felt that it was simply
too expensive to offset any gains, and the remainder felt that paper would
be adequate.
As far as the other question -- OSB vs. plywood for the roof -- most
recommended plywood (minimum 5/8"), while some felt that it was a toss-up.
I've never had anyone say to definitely go with OSB, but I've had many say
to go with plywood. Some cite the possibility of expanding edges with the
OSB leaving visible 'lines' on the roof. Others mention the post-Andrew
Florida law that states you can't use OSB for a roof anymore. While I think
I'll side with the vast majority that recommends plywood (over 90%), I can't
say that I've read any compelling reports that say that OSB is bad -- it's
just that almost everyone seems to think that plywood is better -- for
roofs.
Again -- thanks to everyone that responded -- and if there is anything to
add now that you know where we will live -- I'd love to hear from you. (And
I'll post a summary of the results)
George
Joe Supulski
Foster Vista
Jim,
Could you give your opinion on the OSB issue? It seems there are a lot of abbreviated
names these days, that might lead us to believe that they are scientifically superior
to the products most of us have grown up with. OSB, LVL, PSL, etc. are the terms being
used more and more frequently. Manufacturers are developing higher quality adhesives
and delivering new products that may be comparable with (or exceed) specs on materials
we are most familiar with. They all seem to be surrounded by a heavy advertising
campaign as well. I know that my father would never deck or sheath with anything that
had to be abbreviated. Plywood has served him well. We roof over it, re-roof over it,
weigh it down with snow and ice, and still it performs. It seems to me that there are
a lot of alternatives to the sturdy materials we've been using in (residential)
construction, but most of them seem to reflect a better price tag, rather than better
performance.
Now drywall and galvanized decking screws are a different story :)
HDSherwin
In article <6e29bv$b5n$1...@winter.news.erols.com>, "George Milner"
<george...@erols.com> writes:
>>2. On the other hand, every builder I speak with says to go for plywood
>>instead of OSB for the *roof*
-----------------
I would love to hear any *facts* which support the belief that plywood is
better for a roof than OSB--notwithstanding the consideration that 19/32" OSB
can be purchased for less than 1/2" plywood. The quality (voids) of CDX is what
makes me skeptical.
I would also appreciate hearing what the decision making process was in regard
to the banning of OSB for roofing in Florida--it seems to be a knee-jerk
decision to me.
danh...@millcomm.com
In <3504092B...@wwnet.net>, Randy Hubbard <race...@wwnet.net> writes:
>FWIW,
>
>The *installed price* of TYVEK varies all over the map depending on what a
>builder feels he can get for it... It is NOT difficult to install, and can
>actually be Properly installed with a little common sense and by reading the
>instructions. On new 2000 SF houses in my area of the mid-west the going rate is
>$600-$900. which allows very adequate labor cost for installation, though it's
>rarely installed properly...
Yep, "proper" installation includes taping all seams and around all
windows and doors. But you'll probably never see a regular contractor do
this -- only a DIYer. Excluding the taping, Tyvek is probably easier to
install than tarpaper, since it goes on in such large sheets. The taping
adds some additional labor, but not that much. I would guess that it
would take about one person-day to properly tape an entire average-sized
house. Also, taping around windows can be bypassed if the window trim is
caulked to the Tyvek during installation.
freds
In article <6dujii$8l4$1...@winter.news.erols.com>,
"George Milner" <george...@erols.com> wrote:
>I have 2 questions.
>
>We are involved in making decisions on new house construction. One of the
>choices is thermo-ply or OSB for the exterior walls. There is no cost
>difference. We will probably choose OSB.
OSB material costs about twice as much as t-ply, just call any lumber
yard. A framer will charge more to install OSB wall sheathing than
t-ply. ........ t-ply should cost the home buyer less than OSB
sheathing.
>If we do that, we then choose
>tarpaper or Tyvec. However, Tyvec comes with a $1700 premium. Tarpaper cost
>is built in.
Tyvec is a superior product but over priced at $1700 unless you are
building a house with an extraordinary amount of exterior wall area.
Donald Browning
$1700.00? How big is the house?
It sounds an awful lot like you're getting ripped off. Putting Tyvek on is
less hassle than 15lb. felt.
Don Browning
dbro...@snd.softfarm.com
Chappy
danh...@millcomm.com wrote in message
<6e2heo$q9s$3...@usenet54.supernews.com>...
Maybe I don't charge enough. We recently put some on a new house. It was a
single level ranch, and it took us 2-100' rolls. (we had about 8 feet left
over) We put it on before the windows and doors were installed. It took
the 2 of us just a little over 2 hours to hang it,and to cut out for the
window and door openings were. We had around $240 in the tyvek, nails, and
a roll of tape for any seams. We charged the customer $400, labor and
material. We don't use the stuff very often, so I wasn't really sure what a
fair price was to charge for labor. $160 for slightly more than 4 man hours
seems pretty good.
>
George Milner
I agree -- I heard that in Florida they also outlawed nailguns for roofs at
the same time. I'm thinking that improperly attached OSB may have flown away
with Andrew. In that case, the problem is with installation, not with OSB --
but I need to make an informed decision and most all (over 90%) of those
that contacted me suggested I go for the plywood.
I have no vested interest in this matter except that I want a good roof!
George
HDSherwin wrote in message
<19980310043...@ladder03.news.aol.com>...
Joe Supulski
David J. McBride
ProfEric wrote:
> My recollection, which I believe was from an article in Fine Homebuilding, is
> that the installation WAS the problem. I am not a fan of OSB, but in all
> fairness, what was found was that the OSB was being installed with crown
> staples (pneumatically), and that there was tremendous inconsistency.Most
> staples were too deep, crushing the OSB so the staple pulled through.Some
> staples were not deep enough and pulled out.
Ditto the above. Cost aside, though, I opt for CDX everytime and
everywhere sheathing is called for. However, OSB makes a GREAT
alternative to drywall for garage walls; no floating, no taping, no
painting if you don't want to. And, you can put nails in it without
having a stud handy!
In the Houston area (the last time I took notice) 7/16" OSB was running
about $8.00 give or take; 1/2" CDX was around $10.
Brant Addy
danh...@millcomm.com wrote:
> >Any thoughts are appreciated.
>
> You don't say how big the house is or where you live. In the Frozen North
> you definitely want the Tyvek air infiltration barrier. Farther south it
> probably isn't worthwhile. In any event $1700 sounds awfully high for
> Tyvek unless this is a mansion of some sort. The stuff is no harder to
> install than tarpaper (probably easier) and the extra materials cost would
> run less than $500 for a typical home.
I have to agree with Dan on the cost factor, but I dunno about the
advantage of Tyvek over tarpaper when it comes to air-infiltration. No
one I've ever seen ever tapes (as per the instructions) the top and
bottom seams, not to mention the overlap. So if air can get in the top
& bottom, why not use tarpaper and save the $$$? Besides, from what
I've read in the Journal of Light Construction- See 6/97 article on
Housewrap- Tyvek is yet to be proven in tests where it is subjected to
surficants and extractives (chemicals found in soaps and extracts that
leach out of certain types of woods, like cedar and redwood).
Tyvek is on millions of houses in the US, and very few problems have
resulted BECAUSE of Tyvek, however, plain 'ol tar-paper is on even MORE
houses. You be the judge.
As far as the OSB on a roof is concerned, in my experience, OSB is fine,
as long as it is not exposed to the weather for very long- I wouldn't
use anything less than 1/2" for most roofs, and if the rafters/trusses
are on 24" centers, be sure to use h-clips at midspan. Also, stick with
a high-quality OSB, not the $4.99 farm store variety! <g>
--brant
Brant Addy
ProfEric wrote:
>
> George Milner wrote
> >I agree -- I heard that in Florida they also outlawed nailguns for roofs at
> >the same time. I'm thinking that improperly attached OSB may have flown away
> >with Andrew. In that case, the problem is with installation, not with OSB --
>
> that the installation WAS the problem. I am not a fan of OSB, but in all
> fairness, what was found was that the OSB was being installed with crown
> staples (pneumatically), and that there was tremendous inconsistency.Most
> staples were too deep, crushing the OSB so the staple pulled through.Some
> issues, you may be able to find the article and add some 'exactness' to this.
Eric is right on the money- from my experince as a sub, coming in after
framers on new houses, I'd estimate that 25% of all crown staples have
either partially or totally missed the rafter. Add to that the fact
that they are driven 1/2 way thru the material. WHAT IS HOLDING IT
DOWN? (besides gravity, I mean) Not much.
Installers who use staplers on OSB really need to adjust their pressure
guages so that they just set the staple. Another tip that they should
all use- Hold the nailer perpendicular to the rafter.
--brant
sam coley
George Milner wrote:
>
> I agree -- I heard that in Florida they also outlawed nailguns for roofs at
> the same time. I'm thinking that improperly attached OSB may have flown away
> with Andrew. In that case, the problem is with installation, not with OSB --
> that contacted me suggested I go for the plywood.
>
> I have no vested interest in this matter except that I want a good roof!
>
> George
>
> HDSherwin wrote in message
> <19980310043...@ladder03.news.aol.com>...
> >In article <6e29bv$b5n$1...@winter.news.erols.com>, "George Milner"
> ><george...@erols.com> writes:
> >
> >>>2. On the other hand, every builder I speak with says to go for plywood
> >>>instead of OSB for the *roof*
> >-----------------
> >I would love to hear any *facts* which support the belief that plywood is
> >better for a roof than OSB--notwithstanding the consideration that 19/32"
> OSB
> >can be purchased for less than 1/2" plywood. The quality (voids) of CDX is
> what
> >makes me skeptical.
> >
> >I would also appreciate hearing what the decision making process was in
> regard
> >to the banning of OSB for roofing in Florida--it seems to be a knee-jerk
> >decision to me.
> >
I'm wondering if some of the guys have got OSB confused with 'waferwood'
Joe Barta
Being a roofer and a framer gives me a unique perspective on a few
things. If you're a builder and you're worried about whether to use OSB
or plywood on the roof, either will do. Personally I think plywood is
"better". By the way, the common choice in "1/2 inch" sheathing is
either 7/16" OSB or 15/32" 4-ply CDX plywood (not 3-ply).
If you're really interested in what's better for your roof... increase
the pitch. Increasing the pitch from 4/12 to at least 5/12 will do more
for the roof than almost anything else. (This assuming a good roofer,
decent shingles and proper ventilation).
So, use whatever sheathing material you wish, just keep the pitch of the
roof at least 5/12.
- Joe Barta
Professional roofer, darn good framer, and occassional web page
designer.
ProfEric
George Milner wrote
>I agree -- I heard that in Florida they also outlawed nailguns for roofs at
>the same time. I'm thinking that improperly attached OSB may have flown away
>with Andrew. In that case, the problem is with installation, not with OSB --
My recollection, which I believe was from an article in Fine Homebuilding, is
that the installation WAS the problem. I am not a fan of OSB, but in all
fairness, what was found was that the OSB was being installed with crown
staples (pneumatically), and that there was tremendous inconsistency.Most
staples were too deep, crushing the OSB so the staple pulled through.Some
staples were not deep enough and pulled out. If anyone has retained their back
issues, you may be able to find the article and add some 'exactness' to this.
Eric Hauge
Elan Construction
Clifton, NJ
Jim Ilkay
I don't have a problem with OSB in many applications. Still can't bring
myself around to using it on a sub-floor though.
You're right about new products, materials, etc. A lot of the engineered
wood products available today are superior to the products they replace.
Using glu-lam beams every week it seems. Using MDF and lumber-core in
cabinets and countertops with good results. For paint grade crown and dentil
moldings we use pre-primed MDF, very smooth, clean and straight and paints
like a dream. And of course, there are non-wood alternatives like Hardiplank
siding which is a great alternative to masonite.
Your comment about the price tag being a factor is very true. When you look
at the roofs on some of these new homes and add up the amount of sheathing
that goes into them you realize why builders are using OSB up there. Ask the
typical home buyer if they're willing to part with several hundred dollars
to upgrade to CDX plywood (5/8" is better of course) and see what they have
to say. You'll be ordering OSB 99 times out of a hundred no matter how much
people grumble about how homes used to be built.
Jim Ilkay
bui...@texas.net
Foster Vista wrote in message <3504D5...@louisiana-internet.net>...
danh...@millcomm.com
In <35058...@news1.ibm.net>, "Chappy" <echa...@ibm.net> writes:
>Maybe I don't charge enough. We recently put some on a new house. It was a
>single level ranch, and it took us 2-100' rolls. (we had about 8 feet left
>over) We put it on before the windows and doors were installed. It took
>the 2 of us just a little over 2 hours to hang it,and to cut out for the
>window and door openings were. We had around $240 in the tyvek, nails, and
>a roll of tape for any seams. We charged the customer $400, labor and
>material. We don't use the stuff very often, so I wasn't really sure what a
>fair price was to charge for labor. $160 for slightly more than 4 man hours
>seems pretty good.
Yep, $160 for four hours burdened labor sounds about right to me. I
suppose one could justify another $100 of "markup", like the car makers do
for radios, but it depends on your pricing structure. The original posted
price ($1500??) was a clear ripoff, though, unless it's for Buckingham
Palace.
ed_l...@spamnot.hotmail.com
On Wed, 11 Mar 1998 04:51:03 GMT, "Jim Ilkay" <bui...@texas.net>
wrote:
>I don't have a problem with OSB in many applications. Still can't bring
>myself around to using it on a sub-floor though.
>
>
snip
>Your comment about the price tag being a factor is very true. When you look
>at the roofs on some of these new homes and add up the amount of sheathing
>that goes into them you realize why builders are using OSB up there. Ask the
>typical home buyer if they're willing to part with several hundred dollars
>to upgrade to CDX plywood (5/8" is better of course) and see what they have
>to say. You'll be ordering OSB 99 times out of a hundred no matter how much
>people grumble about how homes used to be built.
>
>Jim Ilkay
>bui...@texas.net
snip
Given what I have seen, in recent years, being passed off as plywood -
I'm not all that sure that OSB is the inferior product. There
shouldn't be any voids or any 1/4" wide gaps in the middle of one face
that run almost all the length of the sheet - like I've seen in CDX
recently.
Shoot, I recently bought a sheet of 3/4" Marine PW - not supposed to
be ANY voids in marine PW (especially at almost $80 per sheet). Sure
was a few small voids in it - just couldn't see them on the edges.
Guess voids "inside" are OK?
Ed.
Frank Vigil
I'm beginning to think that we should have a FAQ about house wraps, since this
question comes up so much!
You didn't state what climate you're building in, but having tested houses
across the country, I can tell you that I've yet to see much (if any) benefits
to house wrap. Additionally, there's new concerns about house wraps actually
aiding moisture problems with certain types of construction (I don't want to
start that whole conversation again).
My advice, and most of my peers in the building science community will say the
same, go with building paper and forget the house wrap. There are far more
effective ways to air seal your house.
Frank
In article <6dujii$8l4$1...@winter.news.erols.com>, george...@erols.com
says...
>
>I have 2 questions.
>
>We are involved in making decisions on new house construction. One of the
>choices is thermo-ply or OSB for the exterior walls. There is no cost
>difference. We will probably choose OSB. If we do that, we then choose
>tarpaper or Tyvec. However, Tyvec comes with a $1700 premium. Tarpaper cost
>is built in.
>
Donald Browning
I agree with your point about the quality of OSB. I resisted using the stuff
for years and was finally forced by competitive cost of OSB to give it a
second look. So far, I haven't had any problems with it and my guess about
the
overall quality mirrors your own. In fact, I have enough confidence in OSB
to sheath the house I'm building for my family with it.
People need to remember that the name brand products from Georgia-Pacific,
Louisiana-Pacific, etc. are all APA rated products.
Don Browning
dbro...@snd.softfarm.com
Larry
Donald Browning wrote:
>
> I agree with your point about the quality of OSB. <snip>
> People need to remember that the name brand products from
> Georgia-Pacific, Louisiana-Pacific, etc. are all APA rated products.
I agree. I just used OSB for all the sheathing on my addition.
I've even laid a few sheets across a muddy, wet part of my yard
for workers to walk across. They're holding up well.
I did go with Weyerhauser Structurwood. It was described to
me as the "Cadillac" of OSB. It cost anywhere from $1.00 to
$1.50 per sheet more than Georgia-Pacific's OSB. But I'm very
happy with it. My 5/12 trusses are on 24" centers and with
ply-clips there is very little give to my roof.
Weyerhauser Structurwood is painted green on its edges... as
opposed to gray on most other brands of OSB.
Larry
ces...@earthlink.net
>
> We are involved in making decisions on new house construction. One of the
> choices is thermo-ply or OSB for the exterior walls. There is no cost
> difference. We will probably choose OSB. If we do that, we then choose
> tarpaper or Tyvec. However, Tyvec comes with a $1700 premium. Tarpaper cost
> is built in.
>
> 1. I don't know whether the added benefits of Tyvec are worth it. We plan on
> staying in the home for 20+ years, but the site manager feels that the Tyvec
> is overkill and not needed -- that the tarpaper wrap achieves nearly the
> same results.
>
> pay the premium.
>
> Any thoughts are appreciated.
>
> Thanks.
>
> George Milner
>
>
you get little or no advantage from Tyvek. In the cold, wet, and windy you get
a big payback in comfort. With proper detailing and sealing the Tyvek will
make a wind- and draft barrier, keeping the house much cozier. You have to
seal all the laps and edges, however.
If you are in a temperate climate, but a wet one, there are various grades of
"tarpaper" (building paper in the trades). You want a Grade D on wood
construction and the codes may require 2 layers over sheathing, if you are
using stucco. I like the Grade D - 60 minutes paper, which is several times
more water resistant than the normal stuff.
-----== Posted via Deja News, The Leader in Internet Discussion ==-----
http://www.dejanews.com/ Now offering spam-free web-based newsreading
Sandy
In article <35081...@news3.paonline.com>, "Donald Browning"
<dbro...@snd.softfarm.com> wrote:
> People need to remember that the name brand products from Georgia-Pacific,
> Louisiana-Pacific, etc. are all APA rated products.
But isn't OSB (oriented strand board) the same stuff that the faulty LP
siding is made of? It sure looks the same to THIS homeowner, who just
spent $17,000 removing her LP lap and T-111 and replacing it with
plywood/vinyl...
-- Sandy
_________________________________________________________
"Whatever you can do, or dream you can, begin it.
Boldness has genius, power, and magic in it." --Goethe
_________________________________________________________
D.Price
The problem with the LP siding is that OSB, which it is made of, is not
intended for long-term exposure to the weather. Moisture will eventually
break it down. OSB is fine for sheathing, since it will be covered.
dcp
Bruce Birbeck
Sandy wrote:
>
> In article <35081...@news3.paonline.com>, "Donald Browning"
> <dbro...@snd.softfarm.com> wrote:
>
> > People need to remember that the name brand products from Georgia-Pacific,
> > Louisiana-Pacific, etc. are all APA rated products.
>
> But isn't OSB (oriented strand board) the same stuff that the faulty LP
> siding is made of? It sure looks the same to THIS homeowner, who just
> spent $17,000 removing her LP lap and T-111 and replacing it with
> plywood/vinyl...
>
> -- Sandy
> _________________________________________________________
Could be, there is a lot of manufactured wood product siding exposed to
the weather out there. If it had thin chips of wood flaking off and it
expanded 2x along the exposed edges, souns like it. Too bad, that must
not have been right application in your case. Sorry that happened to
you. was the T-111 original to the building, and then covered with the
LP? What was between them, Tyvek, of tar paper?
The APA rating and Typar vs tar paper issue twined together makes an
interesting point about the relative longevity of manufactured wood
products and how they're used. If you use OSB for sheathing, subfloor,
of roof, and cover it with siding, flooring, or roofing, it will perform
as advertised. So will plywood. I wouldn't use either outside where I
had a lot of exposed edges to the weather, like lap siding.
If you expose it to the elements, it will deteriorate, delaminate.
Plywood exposed to the elements is T-111. It must depend on how you
care for the siding, but that stuff lasts well. I know of buildings with
it on 20 years, doing fine. They get paint and caulk as necessary. I see
other ones around, 10-12 years old, no attention. The upper sheets are
delaminating at the flashing, some edges below expanding.
I can't help coming back to the moisture migration through a sidewall
without a warm side vapor barrier, being stopped at the tar paper, and
keeping the sheathing damp. Some, but not all, regional areas have
humidity and temperature conditions that can drive moisture through at
such a rate that stopping it is a bad idea. Enter Tyvek/par, which
allows the moisture to penetrate through the infiltration barrier. Tar
paper doesn't.
If you put tar paper over OSB in a dry heating climate, your interior
moisture (no vapor barrier is perfect, and some I've seen installed
resemble funnels directed at some area or other) will condense in or on
it, and it will delaminate over time. So it would seem to me, IMHO.
> "Whatever you can do, or dream you can, begin it.
> Boldness has genius, power, and magic in it." --Goethe
> _________________________________________________________
>
> http://www.pacifier.com/~sandy
--
FWIW;BBB
Sandy
In article <350A8C42...@shorenet.net>, "D.Price"
<danc...@shorenet.net> wrote:
> The problem with the LP siding is that OSB, which it is made of, is not
> intended for long-term exposure to the weather. Moisture will eventually
> break it down. OSB is fine for sheathing, since it will be covered.
Oriented strand board, which I'm sure is what LP is made of (I've seen the
back sides of it as it came off my house,) depends upon a perfect
installation then?
As it was installed on MY particular home, and most others here in the
rainy Pacific NW in the past several years, it turned black, slimy,
expanded, and rotted. ANY product that depends upon a perfect installation
(and no installation is perfect!) shouldn't be installed at all.
My home had the LP lap siding on the front (the bottom edges
expanded/cracked/rotted,) and the T-111 only on the back (also rotted.) I
hear that the T-111 also qualifies as a "vapor barrier," and is a boon to
cheap building contractors as they don't have to do a separate housewrap.
There was no housewrap under my T-111 - only insulation!
Anyway, I know that I will never accept T-111 or any other OSB products on
my home in the future. They rely too heavily on perfect installation, and
as the American homeowner knows only too well, no installation is perfect.
As a matter of fact, I also didn't accept Hardie-plank because it was a
man-made composite. Not that vinyl or plywood aren't man-made, but at
least they're not composites subject to swelling. From now on, it's only
cedar, brick, stucco or vinyl for me!
-- Sandy
_________________________________________________________
danh...@millcomm.com
In <sandy-ya02348000...@news.pacifier.com>, sa...@pacifier.com (Sandy) writes:
>But isn't OSB (oriented strand board) the same stuff that the faulty LP
>siding is made of?
Nope. Hardboard siding is actually more like cardboard. OSB is kind of a
sloppy plywood.
They do have some similar characteristics, though. The quality of both
is greatly dependent on the glue/binder used and how the material is
"pressure cooked".
Bruce Birbeck
Do you have a warm-side vapor barrier? It sounds like your problem could
be moisture attacking your sheathing and siding from both sides. Your
new work could be at risk here, and in a few years you'll be back
replacing it...
>
> "Whatever you can do, or dream you can, begin it.
> Boldness has genius, power, and magic in it." --Goethe
> _________________________________________________________
>
> http://www.pacifier.com/~sandy
--
FWIW;BBB
Robert Allison
Was the T-111 made from the same material as the lap siding? If it was, then it is not OSB. I have never seen T-111 made from OSB, but it is made from masonite. I don't think it would make a very good siding (OSB). I have seen numerous examples of Masonite type products failing from improper installation. I am no defender of masonite, but if it is installed properly,(not perfectly) then it does last quite awhile (10+ years). When I have had to install masonite, I do not use nail guns.
It is impossible to get a nail gun that can set the nails properly everytime. I also seal all the laps, preprime the edges (even though they are already primed) and I used a moisture barrier behind it (felt paper).
I do all of these things (except handnailing) with cedar T-111 also! As far as the hardi-plank siding, I have not heard of a propensity for swelling. In fact, hardi-plank is probably the most durable siding that you could find. It has a fifty year guarantee, does not rot, does not swell, bugs will not eat it, and with a good paint job would probably last a few generations. Some "man made things" are great such as stucco, brick, vinyl and hardi-plank!
--
Robert Allison robert2...@ix.netcom.com
Rimshot, Inc.
Please remove NOSPAM from address to reply.
D.Price
Excuse me, but I believe the Louisiana-Pacific siding in question here
is indeed an OSB product! I have some left over pieces in my shop from a
repair job I did about five years ago on some siding that had rotted
after only four years. The brand name is L.P."Inner-seal". It's OSB with
a paper thin outer membrane of a masonite-like material to form a
substrate for paint. End cuts and nail holes compromise the outer
membrane allowing moisture to get at the OSB and break it down. The
"hardboard" siding you refer to is a whole 'nuther animal.
dcp
D.Price
Sandy,
When you say that no installation is perfec, you're right on the mark.
The other product (Tyvek) in the subject line of this thread, can only
perform as advertised if a perfect installation is done. As you said, no
installation can be done "perfectly", and in the case of housewrap, a
less than perfect installation means water trapped against the
sheathing. I've given up on all housewraps for this reason. They cannot
be installed in a way that water can't penetrate it. When used under
sidings like vinyl where gaps around openings are required, water is
going to enter and if the siding is held on with nails, then there are
holes all over the housewrap. Water entry is inevitable and the
consequenses are extensive rot. I've seen it and I've made good money
repairing it, but I refuse to recommend housewraps under any
circumstances for this very reason. I'd rather spend a little extra on
fuel bills. This is only my opinion but it's based on real situations
and observations in the field. Thanks for listening.
dcp
> _________________________________________________________
D.Price
T-111 is made of plywood. The lap siding Sandy is talking about is
Louisianna-Pacific "InnerSeal" OSB, yes, OSB siding!
Thanks,
dcp
D.Price
Oops, I meant perfect!
dcp
D.Price wrote:
>
> Sandy,
>
> When you say that no installation is perfec, you're right on the mark.
> The other product (Tyvek) in the subject line of this thread, can only
> perform as advertised if a perfect installation is done. As you said, no
> installation can be done "perfectly", and in the case of housewrap, a
> less than perfect installation means water trapped against the
> sheathing. I've given up on all housewraps for this reason. They cannot
> be installed in a way that water can't penetrate it. When used under
> sidings like vinyl where gaps around openings are required, water is
> going to enter and if the siding is held on with nails, then there are
> holes all over the housewrap. Water entry is inevitable and the
> consequenses are extensive rot. I've seen it and I've made good money
> repairing it, but I refuse to recommend housewraps under any
> circumstances for this very reason. I'd rather spend a little extra on
> fuel bills. This is only my opinion but it's based on real situations
> and observations in the field. Thanks for listening.
>
> dcp
>
Sandy
> Do you have a warm-side vapor barrier? It sounds like your problem could
> be moisture attacking your sheathing and siding from both sides. Your
> new work could be at risk here, and in a few years you'll be back
> replacing it...
I just went outside and checked with the siders, and no, I don't have a
warm side vapor barrier. As the house will stand now, I'll have sheetrock
inside, insulation between the studs, plywood on the outside, Tyvek over
that, and then the vinyl lap siding. If moisture STILL gets into the
house, it won't be for lack of effort or money spent!!
Sandy
In article <350C881B...@shorenet.net>, "D.Price"
<danc...@shorenet.net> wrote:
> T-111 is made of plywood. The lap siding Sandy is talking about is
> Louisianna-Pacific "InnerSeal" OSB, yes, OSB siding!
My LP siding, with vertical grooves every 6" and made of OSB, was called
T-111. I understand there is also better T-111 made of cedar plywood, but
as for my project, it was LP/OSB all the way. I'm kind of worried about
the housewrap issues though. It sounds like I might have been better off
just leaving the housewrap off altogether? I had assumed it was a "good"
thing, and didn't question the sider when he said he was going to put it
up. Oh well, too late now I suppose. If it rots, I suppose it'll be my
own bad luck.
Bruce Birbeck
D.Price wrote:
>
> Sandy,
>
> When you say that no installation is perfect, you're right on the mark.
> The other product (Tyvek) in the subject line of this thread, can only
> perform as advertised if a perfect installation is done. As you said, no
> installation can be done "perfectly", and in the case of housewrap, a
> less than perfect installation means water trapped against the
> sheathing.
>
How? From which direction, inside the house, or outside? I must be
missing something here; isn't Tyvek like Gortex, allowing moisture
migration but not air passage?
>
I've given up on all housewraps for this reason. They cannot
> be installed in a way that water can't penetrate it. When used under
> sidings like vinyl where gaps around openings are required, water is
> going to enter and if the siding is held on with nails, then there are
> holes all over the housewrap. Water entry is inevitable and the
> consequenses are extensive rot. I've seen it and I've made good money
> repairing it, but I refuse to recommend housewraps under any
> circumstances for this very reason. I'd rather spend a little extra on
> fuel bills. This is only my opinion but it's based on real situations
> and observations in the field. Thanks for listening.
>
> dcp
>
>
DCP: Just curious, but have you ever done any demo and uncovered
'builders paper' or 'resin paper' or 'pink paper' used under siding, or
under tar paper under siding?
Mostly, today, the stuff is used by builders (and re-modelers) to
protect floors and such.
I've been told by old timers that the paper was used to spread water
leakage out and so to minimumize the damage due to rot. 'Wicking' the
water sideways, not allowing a concentration at the leak point, and
allowing it to be absorbed and evaporated throughout the rest of the
sidewall. I have seen such applications in old buildings (post & beam),
and the sheathing wood was sound, in spite of the evidence of moisture
leaving the paper crinkled and discolored.
Any other recollections, or old-timers on the NG?
> > -- Sandy
> > _________________________________________________________
> >
> > "Whatever you can do, or dream you can, begin it.
> > Boldness has genius, power, and magic in it." --Goethe
> > _________________________________________________________
> >
> > http://www.pacifier.com/~sandy
--
FWIW;BBB
D.Price
Bruce,
Tyvek may indeed allow moisture in the vapor state to get out, but once
water as a liquid enters either by a leak from outside or condensate
from moisture inside, it stays there and is absorbed into the sheathing.
Some of the water may eventually re-vaporize and exit but I think the
sheathing will dry out much faster with no wrap at all.
I once did a remodel where there had been a small leak. Under the wrap
was some of the worst rot I've seen in a long time. Elsewhere on the
house, the plywood under the wrap was heavily mildewed and had a damp,
clammy feel to it, while in one place the wrap had never been installed.
Here the plywood was dry and new-looking. Since then, I have seen other
similar cases of moisture damage behind housewrap.
Yes I have seen many old houses with builders paper under the siding.
One major reason for this was to cover the multitude of open seams
created by the use of individual board sheathing to keep air from
blowing through the walls. With the solid sheet materials we use for
sheathing today, what purpose is served by an air infiltration barrier.
Just seal the seams between sheets and no air will get in.
dcp
danh...@millcomm.com
I wasn't aware of that -- I had assumed that the LP siding was just
another brand of hardboard. I know lots of ill-conceived hardboard brands
suffered from similar swelling conditions, but if the LP siding is as you
describe it I can see why it is in some ways worse.
Bruce Birbeck
Sandy wrote:
>
> In article <6egdmg$bc2$0...@207.3.226.41>, roc...@tidewater.net wrote:
>
> > Do you have a warm-side vapor barrier? It sounds like your problem could
> > be moisture attacking your sheathing and siding from both sides. Your
> > new work could be at risk here, and in a few years you'll be back
> > replacing it...
>
> I just went outside and checked with the siders, and no, I don't have a
> warm side vapor barrier. As the house will stand now, I'll have sheetrock
> inside, insulation between the studs, plywood on the outside, Tyvek over
> that, and then the vinyl lap siding. If moisture STILL gets into the
> house, it won't be for lack of effort or money spent!!
>
> -- Sandy
> _________________________________________________________
Up here in New England, the moisture in the house migrates toward the
outside because there is more inside than out. Nature abhors an
imbalance. When this moisture reaches that point in the insulation where
the temperature is cold enough, it condenses, and gravity pulls it down
to the sill, which rots. A warm side vapor barrier stops (well, slows
down..) this migration. Well, cuts down the volume of water...
In the case of a house in a heating climate with no warm side vapor
barrier and an impervious layer over the sheathing, the water is not
coming from the outside, but from the inside.
Showers, spaghetti, exhalations, and more contribute to the ammount of
moisture within the house. When it is clear outside (no clouds, high
pressure, colder) the RH outside is low. Vapor pressure drives moisture
in that direction via any means.
Typar or Tyvek is used extensivly up here for that reason. It will
allow moisture but not air to pass.
Bruce Birbeck
D.Price wrote:
>
> Bruce,
>
> Tyvek may indeed allow moisture in the vapor state to get out, but once
> water as a liquid enters either by a leak from outside
>
I'm still not clear on how this happens. No gutters? Wind driven rain?
Improperly applied/inappropriate siding? No overhang?
>
> or condensate
> from moisture inside,
>
Is there then no warm side vapor barrier? Without one, in a heating
climate, the problem will return. As expensive as the retrofit would be,
replacing the sheathing every few years seems more expensive.
>
> it stays there and is absorbed into the sheathing.
> Some of the water may eventually re-vaporize and exit but I think the
> sheathing will dry out much faster with no wrap at all.
>
It does seem like a good application for the resin paper, to wick the
water to a place of evaporation.
>
> I once did a remodel where there had been a small leak.
>
From the roof? The siding?
>
> Under the wrap
> was some of the worst rot I've seen in a long time. Elsewhere on the
> house, the plywood under the wrap was heavily mildewed and had a damp,
> clammy feel to it, while in one place the wrap had never been > installed.
> Here the plywood was dry and new-looking. Since then, I have seen other
> similar cases of moisture damage behind housewrap.
>
In each case, was there also a continuous warm side vapor barrier?
I think that siding contractors should verify the presence or lack of a
vapor barrier, and use no housewrap/tarpaper or other impervious sheet
on the cold side. Let it breathe, or let it rot.
I did a heat retrofit on an old house. The heat load was large, becauce
the lady would not put blown-in insulation in the walls. She knew that
the lath-and-plaster inside walls had no vapor barrier. She also knew
that if she insulated the house, the condensation would ruin it. We put
in an oversized heat plant. The extra money she spends for fuel, for
now, is less than the cost to gut and renovate. The building had pink
paper under the clapboards.
--
FWIW;BBB
Frank Vigil
In article <6ekdr1$3ku$0...@207.3.226.53>, roc...@tidewater.net says...
>
>How? From which direction, inside the house, or outside? I must be
>missing something here; isn't Tyvek like Gortex, allowing moisture
>migration but not air passage?
Tyvek does allow moisture to pass through, *in the form of vapor* but not air.
However, the confusion here, is where recent studies are showing that water, in
the form of *liquid* is being trapped between the sheathing and the house wrap.
There are some who believe (I happen to lean this way myself) that this is the
result of several factors, including leaching resins from the siding and also
dust accumulation on the house wrap. To make a long story short, this results
in water being trapped, breaking down of the house wrap material, and moisture
damage as a result. As to direction, I think again you are confusing vapor
pressure (which is not the problem) vs liquid water (which is the problem)
which means we're not talking direction here. Confused? lol
Frank
Brant Addy
Bruce Birbeck wrote:
> Up here in New England, the moisture in the house migrates toward the
> outside because there is more inside than out. Nature abhors an
> imbalance. When this moisture reaches that point in the insulation where
> the temperature is cold enough, it condenses, and gravity pulls it down
> to the sill, which rots. A warm side vapor barrier stops (well, slows
> down..) this migration. Well, cuts down the volume of water...
> In the case of a house in a heating climate with no warm side vapor
> barrier and an impervious layer over the sheathing, the water is not
> coming from the outside, but from the inside.
> Showers, spaghetti, exhalations, and more contribute to the ammount of
> moisture within the house. When it is clear outside (no clouds, high
> pressure, colder) the RH outside is low. Vapor pressure drives moisture
> in that direction via any means.
> Typar or Tyvek is used extensivly up here for that reason. It will
> allow moisture but not air to pass.
Bruce brings up something that I've wondered about for some time now....
when a warm-side vapor barrier should be used.
I live in Eastern Nebraska, where we have HOT summers and COLD winters.
Humidity levels are usually pretty dry. The insulation company that we
deal with doesn't recommend a warm-side vapor barrier, but then the
drywallers come in and say they won't hang drywall without it. So, we
have been putting up 3 mil plastic.
I guess it would be nice to hear some opinions on this- if it should be
standard, or if it is optional based on the climate- (temp & humidity).
--brant
Jim Mundy
In my humble opion Tyvec is over priced and seldom applied correct. Being
in the plastering business i use a D grade breather type asphalt sheathing
paper it is a moisture vapor barrier. We use two layers and @ .03 cents a
square foot its the way to go no matter what type of siding you put on the
building. But not using proper flashings & sealents whats the point. If
you dont use flashing paper at every penetration such as windows, door,
etc. and metal step flashing's at roof's, fireplaces and such you WILL have
water problems. With stucco we have weep screeds at bottoms of the wall so
any water that makes it to the paper it has some where to get out. Now the
E.I.F.S industry is adopting a back-up weather barrier modeled after the
Portland cement stucco standards.
Jim Mundy
http://Mundybros.com
D.Price
I'm currently seeing problems where rain is getting behind the vinyl
siding at the ends where it terminates in J-channels around doors and
around windows. Especially vulnerable are the lower corners of windows
where the siding is cut to fit around these corners. With vinyl siding,
GAPS ARE REQUIRED in order to prevent buckling. These gaps create
funnels to catch water and send it right behind the siding. The water
(and air) then can enter the housewrap through any of the thousands of
nail holes punched in it by the siding nails.
As far as warm side vapor barrier is concerned, I'm totally in favor of
it, but I doubt that this will guarantee that absolutely no vapor will
get through from maybe the crawl space through framing gaps, cracks in
lumber , etc. I've had customers refuse inside poly believing it causes
moisture retention in the walls. In my mind, housewrap is just a
potential problem. In light of the risks, I'll steer clear of it.
dcp
Bruce Birbeck wrote:
> No. I'm not confused. I am curious about the SOURCE of this water. Rain
> or cooking? Where did it come from? Which direction, inside, or outside?
> That it is between the housewrap and the sheathing is understood. This
> caused the rot.
> I want to know:
> What is the climate?
> Is there a warm side vapor barrier?
> If the answer to the first is "warm", and the second "no", then I guess
> the water came from rain, and got in through the little staple holes,
> and all the siding nail holes.
> Or, could high outside humidity migrate into the structure, toward a
> place with a lower humidity (A/C in the muggy days) and condense within
> the wall cavity because the house was so cool relative to the outside?
> If the answer to the first is "cold" and the second "no", then you have
> a setup to rot the sheathing once again REGARDLESS if you use housewrap
> in the residing of the house or not. IMHO, of course. If you didn't use
> house wrap, the moisture would have a better chance to escape, of
> course. Without a vapor barrier, and with no sheathing paper, how many
> natural air changes per hour would you expect of the average house?
> Your statement of the water being "trapped" on that side of the
> housewrap indicates that the water was trying to 'escape' from the
> house.
> Use of a warm side vapor barrier will lessen the ammount of water to be
> trapped.
> I have heard that Tyvek will pass water (liquid) through in one
> direction only. Interesting? I've also heard that Tyvek breaks down in
> sunlight and looses that ability; the outside 'shiny' surface gets
> degraded, and water will pass through both ways. Typar is an improvment,
> they say, and has UV resistance to prevent this. Most houses aren't
> sided within 3 weeks of the time that the housewrap is installed.
> --
> FWIW;BBB
Bruce Birbeck
danh...@millcomm.com
In <350EBA...@navix.net>, Brant Addy <ba7...@navix.net> writes:
>I live in Eastern Nebraska, where we have HOT summers and COLD winters.
>Humidity levels are usually pretty dry. The insulation company that we
>deal with doesn't recommend a warm-side vapor barrier, but then the
>drywallers come in and say they won't hang drywall without it. So, we
>have been putting up 3 mil plastic.
>
>I guess it would be nice to hear some opinions on this- if it should be
>standard, or if it is optional based on the climate- (temp & humidity).
The question is: What is the typical dew point in the summer. If the dew
point is normally lower than the inside temperature then you will have no
problem with an inside vapor barrier, and I would strongly recommend it
(along with the Tyvek -- it can get windy there).
A condensation problem can only occur when the dew point of the air is
above the temperature at the point where one is concerned about it. If
the temp inside is around 70F, and the relative humidity is 40, then the
dew point is somewhere around 40F. If inside air comes in contact with
something colder than 40F then the moisture in the air will begin to
condense.
To have a summertime problem, with the outside temp at, say, 80F, and the
inside temp 70F, you would need a daytime relative humidity in the 60s,
close as I can tell interpolating in this chart. Certainly there are
times when the humidity gets that high in the interior of the country, but
not for sustained periods. And there is essentially no potential for
trouble at all if you don't air-condition.
Joe Supulski
Brant Addy
D.Price wrote:
>
> I'm currently seeing problems where rain is getting behind the vinyl
> siding at the ends where it terminates in J-channels around doors and
> around windows. Especially vulnerable are the lower corners of windows
> where the siding is cut to fit around these corners. With vinyl siding,
> GAPS ARE REQUIRED in order to prevent buckling. These gaps create
> funnels to catch water and send it right behind the siding. The water
> (and air) then can enter the housewrap through any of the thousands of
> nail holes punched in it by the siding nails.
Dan,
The June 1997 issue "Journal of Light Construction" had a good article
describing several vinyl siding details.
I've done quite a bit of siding, but I picked up ONE good tip from that
article that can help alleviate the problem you just described:
I'll try to explain this without losing you- You've got your J-channel
installed around the window, right? Before you put on the piece of
siding that will go around the bottom of the window, do this: Measure
the distance from the interlock of your last row of siding... to the
spot where the side j-channel meets the bottom one. Add 4 inches. Cut
a piece of aluminum trim coil that length and about 8" wide. cut a 4" x
4" square out of the corner. This is your corner flashing! Pull any
nails that are in the way, and tuck it behind the nailing fins of the
j-channels. The bottom of the corner flashing should overlap the
interlock of the last row of siding. You should still be able to
interlock the next row, if the flashing is not too long.
What this will do is shed any water that is running down the j-channel
into the siding's interlock. It will then be able to weep out of the
siding. You may want to drill additional (larger) weep holes at these
spots.
This won't keep water that enters along the window from getting in
behind the j-channel- that still has to be caulked- a major weakness of
vinyl siding as far as I'm concerned!
--brant
danh...@millcomm.com
In <350F4D02...@shorenet.net>, "D.Price" <danc...@shorenet.net> writes:
>As far as warm side vapor barrier is concerned, I'm totally in favor of
>it, but I doubt that this will guarantee that absolutely no vapor will
>get through from maybe the crawl space through framing gaps, cracks in
>lumber , etc.
You don't need to guarantee that absolutely no vapor gets through, you
just need to reduce the amount that gets through by roughly a factor of
ten. This will then assure that the relative humidity stays below the dew
point.
bean...@msn.com
We are completing construction on a second home in a coastal area using
Certainteed Cedar Impressions vinyl siding. Cedar Impressions is a heavier
siding which comes in smaller interlocking pieces than standard siding. I
saw a lot of it when visiting the North Carolina seashore last year.
One-half inch CDX plywood over 2X6 studs with Simpson Barricade housewrap is
proposed under the siding. Has anyone used Cedar Impressions? What is the
proper moisture barrier? If need be, can a second layer of housewrap be
placed over the Barricade?
As you can probably guess, I am not convinced of the effectiveness of either
the Cedar Impressions or the Barricade, but windy conditions make the
heavier siding attractive.
I'd appreciate any ideas.
-----== Posted via Deja News, The Leader in Internet Discussion ==-----
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David J. McBride
bean...@MSN.com wrote:
>
> We are completing construction on a second home in a coastal area using
> Certainteed Cedar Impressions vinyl siding. Cedar Impressions is a heavier
> siding which comes in smaller interlocking pieces than standard siding. I
> saw a lot of it when visiting the North Carolina seashore last year.
>
> One-half inch CDX plywood over 2X6 studs with Simpson Barricade housewrap is
> proposed under the siding. Has anyone used Cedar Impressions? What is the
> proper moisture barrier? If need be, can a second layer of housewrap be
> placed over the Barricade?
>
> As you can probably guess, I am not convinced of the effectiveness of either
> the Cedar Impressions or the Barricade, but windy conditions make the
> heavier siding attractive.
I live in the Texas Gulf Coast region and would *never* put either a
house wrap *OR* vinyl siding on any house that I built. I cannot think
of any better way than to put a a vapor barrier on the outside of a
structure, trapping moisture in your wall cavities and insulation. I
have to believe mold and mildew problems are only a short distance down
the road for anyone who does. Your walls need to breathe.
Cement board lap siding (or cedar lap siding) over 15 pound felt over
the 1/2 inch CDX or over 1/2 inch asphalt impregnated sheathing (1/2
inch CDX at all corners nailed properly OR inlet bracing at all
corners). Oil base exterior primer (back prime, too, if cedar siding)
and two coats of PPG Manor Hall or equivalent latex top coat. Cedar or
No. 1 kindred 1X4 trim, primed and painted as above. The cement siding,
Hardiplank in particular, comes in a variety of patterns and a 50 year
warranty. Yes, you'll probably have to paint again in 8 or 10 years.
--
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Dj...@worldnet.att.net
David J. McBride
Houston, Texas
Strctbnd
In reply to DjMcB's suggestion; Would'nt the felt paper/asphalt impregnated
sheathing create the same "vapor barrier on the outside" problem as the house
wrap?
David J. McBride
The felt paper, though overlapped, is hardly airtight. Advocates of
house wrap will argue that Tyvek type wraps "breathe" and I believe
them. I also believe that the rate of moisture migration from a wall
cavity wrapped with Tyvek is significantly less than a wall cavity with
felt and clapboard siding and far, far less than a wall with vinyl
siding *over* house wrap.
I like to remind clients, on those occasions when the issue arises that
the one and two hundred year old homes that are still in use today *are*
that old in large part because there is *nothing* in the wall cavities;
few are even felt wrapped under the siding. The point is, of course,
moisture is free to migrate at will from within the wall cavities.
The caveat in all this is that we are dealing with warm, humid climates
such as the Gulf Coast or the Southeast Atlantic Coast. The rules
change when you get to cold, dry climates. I leave that to people who
are infinitely more familiar with that I am.
Tom Staresinic
> "David J. McBride" (Dj...@anotherworldnet.att.net) writes:
>> Strctbnd wrote:
>>>
>>> In reply to DjMcB's suggestion; Would'nt the felt paper/asphalt impregnated
>>> sheathing create the same "vapor barrier on the outside" problem as the house
>>> wrap?
>>
>> The felt paper, though overlapped, is hardly airtight.
>
> According to the last Tyvek specs. i saw, Tyvek let through about 9 times
> less air than 15 pound asphalt felt (.034 vs .27 litres per square metre per
> second at a pressure differential of 75 MPa). The building code in my area, a
> northern climate, the material that provides the 'principle resistance to
> air leakage' (some refer to it as the 'air barrier') should not be more
> than 0.02 so the Tyvek available in my area last year (Tyvek says that
> there newer material will meet this requirement) did neet strictly meet
> the code requirement (other codes may have a different definition for the air
> barrier requirement).
>
>>Advocates of house wrap will argue that Tyvek type wraps "breathe" and I
>>believe them.
>>I also believe that the rate of moisture migration from a wall
>> cavity wrapped with Tyvek is significantly less than a wall cavity with
>> felt
>
> Water vapour permeance rating for Tyvek is around 55 Perms compared to
> .06 for polyethylene and 1-6 range for 15 pound asphalt felt. The
> traditional vapour 'barrier' (more appropriately refered to as
> 'retardent') definition is 1 Perm. These values can vary depending under what
> conditions the permeability test (often ASTM E-96) is done;
>
>> The caveat in all this is that we are dealing with warm, humid climates
>> such as the Gulf Coast or the Southeast Atlantic Coast. The rules
>> change when you get to cold, dry climates. I leave that to people who
>> are infinitely more familiar with that I am.
>
> i think the permenace values i stated are for no more than 50% relative
> humidity (the permeability may be much lower in very high RH conditions).
>
>
>
Pgengle
In article <199804040652...@ladder03.news.aol.com>, strc...@aol.com
(Strctbnd) writes:
>In reply to DjMcB's suggestion; Would'nt the felt paper/asphalt impregnated
>sheathing create the same "vapor barrier on the outside" problem as the house
>wrap?
This thread jsut seems to go 'round and 'round.
Both Tyvek and felt paper are moisture, but not vapor barriers. Housewraps
have the added benefit of additional air sealing when properly applied.
Any vapor retarder can trap moisture inside the wall, if there's moisture there
to start with. The key is to keep it out. On the Gulf Coast (warm & wet
(cooling climate), you actually want a really good air AND vapor barrier on the
outside, none on the inside. Well taped housewraps might suffice, but 10 mil
poly over the sheathing would be better.
Pete Engle, PE
Almost Home
Rumson, NJ
Frank Vigil
>
>In reply to DjMcB's suggestion; Would'nt the felt paper/asphalt impregnated
>sheathing create the same "vapor barrier on the outside" problem as the house
>wrap?
I wonder if this old chestnut is ever going to die? House wraps block wind,
not moisture...they are intended to be used as an air retarder while
still allowing moisture migration to occur. Thus, wrapping a house on the
outside with the stuff is not an issue.
However, I still contend they don't work as air retarders (I've tested far too
many houses with them, and see no difference in the air tightness), are not
worth the money and are suspected as contributing to moisture problems as a
result of contact with the cladding on the house.
There are cheaper, more effective and less problemtic ways to air seal houses.
Frank
Robert H
I would be interested in your "other methods" of sealing the home from air
infiltration and possible wind driven rain. In Western Washington these are
two big problems for current new homes. I have used building paper and then
switched to Tyvek and have been very pleased with the results. An older
home that I remodeled had building paper but when we resided, we went with
Tyvek. The homeowners told me the home was always cold before the Tyvek
went up but now stays warmer or the temperature remains more consistent.
Please let me know what you have found out. I appreciate the help.
NOTSPAM aec.ncsu.edu (Frank Vigil) wrote in message
<6gb03k$4i8$3...@uni00nw.unity.ncsu.edu>...
D.Price
I think a more direct approach to air infiltration is more effective. By
this I mean sealing the actual gaps or seams that the air is going to
blow through. It strikes me as ludicrous to cover the entire house with
a "loose" membrane to try to prevent air from entering the seams in the
sheathing. Most of what is being covered is already an air barrier
(plywood, osb, etc.).Still, any air that enters through the housewrap
membrane by way of untaped joints, nail holes (from the siding), and the
holes made by the staples in the wrap, is still going to blow through
the joints in the sheathing/framing. If these joints are sealed
directly, no air CAN enter and no housewrap is needed at all. Also
eliminated is the chance of moisture entrapment that can and does happen
with housewrap in the event of a leak, or condensation. wetted sheathing
can dry out much more easily if air can circulate across it's surface.
Joints can be caulked as the framing/sheathing is under way or as the
siding is installed. There is also a product made by the Benjamin Obdyke
Co. called GapWrap that is a flexible Tyvek-like tape about 3" wide that
has adhesive along only the edges. This way it can span across a seam
and still allow independent movement of the adjoining surfaces...nice
product. Anyway, house wraps are not a thinking person's solution to the
air infiltration problem.
dcp