R-30 in 2x6 walls?
Eric
for a 20'x50' metal building, and the insulation would be approximately one
inch from the steel wall to reduce condensation risks. R-30 is 9.5 inches
thick. This means the insulation would extend another 3.5 inches out of the
2x6.
Does anyone see any issues with the insulation not being completely within
the inside wall? If so, what are my options? I know I could use R-25, but
I'd like to use R-30. Thanks in advance.
Eric
Thomas G. Baker
Eric wrote:
I don't see any problems resulting from the insulation being deeper than the
studs. I'm not sure how you intend to hold the insulation in place, or whether
the space between metal wall and insulation will allow enough air movement to
mess with the air trapped in the insulation.
TB
Bill Seurer
> the insulation would be approximately one
> inch from the steel wall to reduce condensation risks.
Isn't there usually some sort of sheathing under the steel? And what
about a vapor barrier on the inside? You are still going to have
moisture problems in the gap.
You might want to consider a cheap double wall using 2x4s/2x3s on the
interior of the 2x6s. Then you can use R19 insulation in the 2x6 wall
and R11 insulation in the interior wall. The insulation may well cost
less than the R30 stuff.
--
Bill Seurer Work: seurer AT us.ibm.com Home: Bill AT seurer.net
http://www.seurer.net/ (replace " AT " with "@" to email me)
John Taylor
Are you saying the inside face of the 2x6 is going to be 10 1/2" in from the
steel siding? If so, I can't think of any problems. If there is going to
be condensation, it seems like it would occur directly behind the sheetrock,
where the vapor barrier should be. Hence, the reason for a vapor barrier in
the first place. By the way, where are you? Is R30 standard, or does your
building have some temperature sensitive function?
JT
Eric wrote in message ...
dec...@owt.com
"Eric" <Er...@nospam.com> wrote in message
news:UDUd7.44360$gj1.4...@bgtnsc05-news.ops.worldnet.att.net...
> I'd like to use R-30 in some inside walls using 2x6s. The inside walls
are
> for a 20'x50' metal building, and the insulation would be approximately
one
> inch from the steel wall to reduce condensation risks.
Are you saying you want to insulate the walls against the exterior wall
sheets between the sheeting girts?
If that is the case, there is a better, faster & cheaper way to do this.
Drop a line if you're interested. I'll explain it. And no, I'm not in the
selling business but am in the metal building erection business. 22 years.
Fritz
Yaofeng
By all means, use it. It'll be better than R25 but less than R30.
Dan Hicks
The problem you will have is that fiberglass really needs a "solid"
surface on both sides to be reasonably effective. Housewrap or
brownboard sheathing would work.
--
Dan Hicks
A smile is an inexpensive way to improve your looks.
Eric
front of the frame (warm-side). I either might have to use more staples, or
perhaps add some steel bands across the back of the frame to provide more
support for the insulation.
As far as how much space between the insulation and the metal outside wall,
do you think 1 inch is enough? Perhaps 2 to 3 might be better, but that
would reduce the square footage. The metal building's walls are corrugated
in shape and have 3/4 inch vertical cavities which would aid in air
movement. So it would be alternating distances of 1 inch and 1 3/4 inches
away from the insulation.
Eric
"Thomas G. Baker" <tgb...@mindspring.com> wrote in message
news:3B78314B...@mindspring.com...
Eric
building which was used to house a boat and serve as a workshop and has
simple corrugated walls. It's in great shape though. I still plan on
having a moisture barrier. Perhaps 6 or 8 mil over the insulation
(warm-side). My only concern was that 3.5 inches of the R-30 would extend
beyond the 2x6 frame. I'm curious if this reduces the R value. Does it
have to be in the frame to get the complete R value? There is also some
debate in these newsgroups about sqeezing the insulation in the frame to
make it fit...
Interesting point on the double wall. I think I may look into it. However
cost isn't really a motivating factor. Doing a simple 2x6 wall would be
faster than a double wall.
Eric
"Bill Seurer" <Bi...@seurer.net> wrote in message
news:3B783CB3...@seurer.net...
Eric
the walls have vertical cavities which are approximately 3/4" deep and
alternate. So the range would be 10 1/2" to 11 1/4". That would further
aid air movement.
However, I'm really interested if I will get the full R-30 value if 3.5
inches of the insulation extends from the frame. Does the batt have to be
totally enclosed in the frame in order to achieve the full rating?
I'm in TX and R30 isn't the standard. I believe R-13 is. However, I am
framing the building and want to superinsulate it.
Eric
"John Taylor" <Jo...@bwaarchitects.com> wrote in message
news:0LYd7.7673$Kl2.7...@newsread1.prod.itd.earthlink.net...
Eric
other options. I was thinking of doing 2x6 framing 10 1/2" from the steel
walls and placing R-30 (9 1/2") in them. I'm curious if I will get the full
R-30 value if 3 1/2" of the insulation extends beyond the 2x6 frame. Are
there cheaper or better ways to superinsulate a metal building?
Eric
<dec...@owt.com> wrote in message news:9l9m10$4k3$1...@news.owt.com...
Eric
Eric
"Yaofeng" <yc...@bmwe30.net> wrote in message
news:e89d1e3e.01081...@posting.google.com...
Chas Hurst
Eric <Er...@nospam.com> wrote in message
news:gn%d7.44768$gj1.4...@bgtnsc05-news.ops.worldnet.att.net...
Nnails56
>inch from the steel wall to reduce condensation risks.
Not sure why you would do this. On all newly constructed steel buildings the
insulation is tight to the steel. Normal procedure is to make sure that you do
NOT have any air cavities between the wall and ceiling panels. That is why you
don't have to ventilate the ceiling of a pre-engineered steel building, because
there are no cavities for condensation to form.
Eric
So I could put a brownboard sheathing around it and then place it in the 2x6
framing?
Eric
"Dan Hicks" <danh...@ieee.org> wrote in message
news:3B78817E...@ieee.org...
Dan Hicks
spaced 3.5 inches or so from the studs. The important thing is that it
be in contact with the insulation so that there is no air circulation
pocket that would degrade the value of the insulation.
--
Dan Hicks
Everywhere is walking distance if you have the time. --Steven Wright
Eric
small building (1,000 sq ft), and that it is usually done on larger
buildings. Do you know anything about the R values and costs for a 1,000 sq
ft steel building? Thanks.
Eric
"Chas Hurst" <rose...@early.com> wrote in message
news:vM%d7.5154$mo3.1...@nntp2.onemain.com...
Eric
is a vent on the roof which is opened to varying degrees using a chain, and
the building has central AC/heat. I want to put in some framing with a lot
of insulation, say R-30, and hang a drop ceiling with glass batts on top as
well. Under this scenario, I had planned on opening the roof vent all the
way to get rid of the heat much like an attic ridge vent. Does this make
sense or am I completely off track? An energy auditor had mentioned to me
that I should just apply styrofoam sheets to the wall with glue and then
frame it with glass insulation, but I was concerned with condensation as
well as using stryrofoam due to its flammability.
Eric
"Nnails56" <nnai...@aol.com> wrote in message
news:20010813222604...@mb-cg.aol.com...
Eric
frame wall in front of it. I might have to look into that. One of the
other posters said that insulation should always be applied directly to the
metal walls, so that condensation does not build up in the wall cavities.
Are you familiar with this?
Eric
"Dan Hicks" <danh...@ieee.org> wrote in message
news:3B7893BA...@ieee.org...
Chas Hurst
might offset the higher cost. It's done locally here (SE Pa) all the time.
As far as costs, use the yellow pages or your local lumber yard to locate a
contractor and get some estimates.
Eric <Er...@nospam.com> wrote in message
news:vu0e7.44919$gj1.4...@bgtnsc05-news.ops.worldnet.att.net...
Eric
to put some drywall up as well to make the place a little more formal (e.g.
home office), would I even need a moisture barrier or even insulation for
the framing?
Eric
"Chas Hurst" <rose...@early.com> wrote in message
news:cI0e7.5166$mo3.1...@nntp2.onemain.com...
Thomas G. Baker
Eric wrote:
As I understand the arrangement, you intend to leave unfaced batt one inch
from a metal wall panel. I want to revise my comment to more nearly agree with
Dan Hicks and Erik Deckers and John Taylor ( if I remember correctly ). The
batt is not going to lose insulation value and may suffer some physical damage
from moving air and perhaps moisture if it's not protected out there. I think
I misunderstood the arrangement when I first replied. That is, the conditions
in the assembly are not good for long term maintenance of the batt insulation.
Tom Baker
ameijers
several years....
I would not recommend naked fiber insulation in a no-acccess space like
that, next to a metal outside wall. It will still suck moisture and attract
small living creatures. Or where you talking about styrofoam sheets? Is
there a particular reason you don't want to use the insulation they sell for
pole barns, which is encased against rodents?
Unless space is at a premium, or you want to poke windows through the inner
and outer walls, I'd hold the inside wall back further, and skin both sides
of the inner wall. If the barn is draft-free, the dead space and thermal
break will keep the heated space a lot warmer. The prefab offices they use
in commercial warehouses are usually set up like that.
aem sends....
Eric <Er...@nospam.com> wrote in message
news:UDUd7.44360$gj1.4...@bgtnsc05-news.ops.worldnet.att.net...
Eric
applying sheets of insulation directly against them? The building is pretty
much sealed tight with a garage door and a normal door. No windows.
There's a ridge vent which on the roof which can be opened with a chain. I
usually keep it closed when the AC is on. I don't think rodents would be an
issue. I just need to insulate it and make it a little more formal with
drywall to save electric costs. I was thinking of using standard faced
fiberglass batts between the studs, with some distance, perhaps an inch or
two, from the metal skin. Do you see any issues with this? Thanks.
Eric
"ameijers" <aeme...@worldnet.att.net> wrote in message
news:Eale7.16484$1p1.1...@bgtnsc04-news.ops.worldnet.att.net...
Walt
have exposed insulation in an area which is deemed to be
inhabitable.
v.
<Jo...@bwaarchitects.com> some motley fool wrote:
>.... If there is going to
>be condensation, it seems like it would occur directly behind the sheetrock,
NO NO NO NO NO
1) There is a temperature gradient within the wall. That is, at the
inside face it is "room" temp, at the outside face it is outside temp.
2) Where the gradient falls below the dew point of the air within the
wall, that point & outboard is where the condensation would occur.
3) If there is insulation, that point is almost assuredly NOT directly
behind the sheetrock, the sheetrock will be quite warm. Usually it's
within the insulation somewhere.
4) The reason for a vapor barrier on the warm side is to reduce the
humidity inside the wall to the point where a) the dew point is very
low for such dry air anyway, and b) there is so little absolute
moisture that it can transpire out.
Here, unfortunately, the outer steel shell is pretty much vapor proof,
so care must be taken to prevent trapped moisture inside it. Contrast
to typical framed construction with "Tyvek" wrap, which is liquid
proof but vapor permeable so that vapor can escape from the inside of
the wall.
Steel building can of course be insulated, there are thousands of
commercial ones. I would give serious thought to the possibility of
venting the space between insulation and steel, as if it were an
attic.
good luck,
-v.
v.
fool wrote:
>Check your local building codes. You may not be allowed to
>have exposed insulation in an area which is deemed to be
>inhabitable.
>
Of course you can. That's the place you CAN have it. Think every
non-floored attic. Think my basement in the wall between the finished
& unfinished space, that unfinished side being unheated and not
surfaced (new construction, inspected).
It should be covered in the habitable spaces, you have it backwards.
-v.
ameijers
metal, even with an air space. At least a vapor barrier, or even cheap
masonite siding nailed to the outside of the studs- a building within a
building.
But now that later posts have given more details of what you are planning,
I'd say to go with something intended for metal construction- the
fully-wrapped bats or the foam-in-place stuff. Why reinvent the wheel? When
in doubt, copy how the experts do it. Insulate the actual outside wall, and
then mount inside wall on furring strips, or even an inner wall of steel
studs (suprisingly cheap and sturdy, and rot/rodent proof.) Personally,
rather than drywall, I'd use something rated for a damp area, like
plastic-coated paneling. Factory seconds of 4x8 sheets usually aren't too
hard to track down. Condensation aside, the slab floor and overhead door
mean that there will sometimes be high humidity conditions. A
plastic-skinned panel will be much easier to clean in a shop/garage
environment, than painted sheetrock would be.
aem sends...
Eric <Er...@nospam.com> wrote in message
news:rCye7.10935$Ki1.8...@bgtnsc06-news.ops.worldnet.att.net...
Walt
"Inhabit" means:
1 : to occupy as a place of settled residence or habitat
: live in <inhabit a small house>
2 : to be present in or occupy in any manner or form
<the human beings who inhabit this tale -- Al
Newman>
So, "inhabitable" space is finished space.
In your new and inspected construction, do you have exposed
insulation in your living room? Your kitchen? Your bedrooms?
Or similar inhabited space?
Do you also think that "inflammable" means "not flammable"? :)
Joe Barta
I found this interesting. I looked it up. Turns out you are BOTH
right. Inhabitable means both "habitable" AND "not habitable". Go
figure. I'll let someone else look up "inflammable".
===========================================
151 "Inhabitable" web1913 "Webster's Revised Unabridged Dictionary
(1913)"
Inhabitable \In*hab"it*a*ble\, a. [L. inhabitabilis. See
{Inhabit}.]
Capable of being inhabited; habitable.
Systems of inhabitable planets. --Locke.
151 "Inhabitable" web1913 "Webster's Revised Unabridged Dictionary
(1913)"
Inhabitable \In*hab"it*a*ble\, a. [L. inhabitabilis: cf. F.
inhabitable. See {In-} not, and {Habitable}.]
Not habitable; not suitable to be inhabited. [Obs.]
The frozen ridges of the Alps Or other ground
inhabitable. --Shak.
151 "inhabitable" wn "WordNet (r) 1.6"
inhabitable
adj : fit for habitation; "the habitable world" [syn:
{habitable}]
0s]
===========================================
- Joe Barta
Eric
least a few inches distance between the insulation and the steel walls, have
a moisture barrier on the warm side under the drywall, add a drop ceiling,
add insulation to the drop ceiling (lay batts on top), and then open the
ridge vent in the roof a bit, this should ventilate it ok, right? This
would be similar to having an attic. There are no soffits in the building
though. Hopefully the hot air can be efficiently let out through the roof
vent.
I have heard that even with the roof vent closed completely, that a minimal
amount of air still gets out. This was from somone who constructs metal
buildings. He had said this should be sufficient to reduce condensation
issues. An alternative option which he mentioned was called 'simple saver',
where wires and boards are run below the purlines and in between the girts
and insulation batts are placed there. However, I'd like the place to be
more finished for a home office.
Eric
"v." <v.viv...@KILLSPAMverizon.net> wrote in message
news:3b7b2b76...@news.bellatlantic.net...
TW
but why would anyone want a space between the outside surface of batt
insulation and and an exterior metal wall panel?
If you have a vapor retarder like foil with tape on the inside of the
insulation (warm side), and unbroken sheet metal panels exposed to
weather, why not install the studs (wood?) as close to the metal panels
as possible, place insulation fully filling the space between studs, and
apply interior finish?
Walt
"No, it is a desert topping."
"Stop it, you are both right! It is both a floor wax and
a desert topping!" :)
Sorry, that Saturday Night Skit came to mind.
Dan Hicks
>
> I'd like to use R-30 in some inside walls using 2x6s. The inside walls are
> for a 20'x50' metal building, and the insulation would be approximately one
> inch from the steel wall to reduce condensation risks. R-30 is 9.5 inches
> thick. This means the insulation would extend another 3.5 inches out of the
> 2x6.
>
> I'd like to use R-30. Thanks in advance.
>
> Eric
This is developing into an epic.
There are two important things to keep in mind here, assuming we are
talking about temperate zone construction:
1) Fiberglass will loose effectiveness (and be a bonanza for rodents and
bugs) if left uncovered on either side. The "inside" should be covered
with a suitable vapor barrier and a suitable hard covering. The
"outside" needs to be covered with some sort of wind barrier without
creating a heavy vapor barrier. Cheap fiberboard sheathing would work,
or even just some framing with housewrap covering it. Whatever covering
is used, however, should be in physical contact with the insulation (no
air gap) in order to maximize the effectiveness of the fiberglass and
minimize opportunities for critters.
2) OTOH, you generally should not place fiberglass insuation directly
against a metal wall, since the metal wall will act like a vapor barrier
and promote condensation. Ideally there should be several inches of air
space between the outer sheathing of the insulation and the metal wall.
The air space should also be vented (so that moisture and heat can
escape)n, though it wouldn't have to be vented as well as a typical
frame attic.
--
Dan Hicks
Those who would have nothing to do with thorns must never attempt to
gather
flowers.
Eric
building with central AC/heat. I want to frame it (wood 2x6s) with
insulation to make it more formal and to save electric costs as well.
My reasoning of placing the framing and insulation at a distance from the
metal walls (a few inches) was that I was concerned with condensation. The
metal walls are unbroken and in excellent condition. Do you feel that the
insulation should be placed directly against the metal walls? I believe
that's what you're stating.
Actually, I would prefer to place the studs as close to the metal walls as
possible in order to conserve square footage. However, I am wondering if
there would be any condensation risks.
Eric
"TW" <nov...@erols.com> wrote in message news:3B7BFE1D...@erols.com...
Eric
I believe this solution is coming together with all of your help. I
appreciate the candid responses of everyone in this newsgroup.
So placing the framing too close to the metal walls where the insulation
touches the metal seems to be a no-no. You have a new point which I don't
believe has been brought up. I should ensure that the insulation is sealed
tight on BOTH sides. Basically a vapor barrier on the warm side (perhaps 6
or 8 mil), but a sheathing of some sort on the other side FACING the metal
walls. The sheathing could be housewrap (Tyvex?) or cheap fiberboard
sheathing (any brands or vendors?).
What this sounds like is that I have to place a sheathing on the frame on
the side facing the metal wall prior to raising it and securing it to the
foundation. Then, after electric and other routings are completed, I can
insulate it with fiberglass batts, add a moisture barrier, and then
sheetrock.
Also, the roof vent should be at least slightly open to ensure enough
ventilation. This sounds like a pretty solid plan. Have I missed anything?
I also plan on adding a drop ceiling and placing batts on top of this to
create a pseudo-attic if you will.
Eric
"Dan Hicks" <danh...@ieee.org> wrote in message
news:3B7C68E6...@ieee.org...
Eric
batts should be sealed on BOTH sides. This is beginning to be clearer.
Thanks for the paneling advice. However, I'd like to convert the place into
a home office with a separate game/library room. I think drywall and a nice
drop ceiling would be more appropriate right now. Perhaps I can use that
paneling idea a few years later when I need the place to park a boat.
Eric
"ameijers" <aeme...@worldnet.att.net> wrote in message
news:vVGe7.47386$gj1.4...@bgtnsc05-news.ops.worldnet.att.net...
TW
Yes, I see no reason for the gap. Your interior vapor barrier (foil is
best) if taped at seams and not perforated, will keep humid air on the
warm side, preventing condensation. Also, since no metal skin is
totally airtight, any small amount of moisture should find it's way out
the seams of the metal panels.
TW
> best) if taped at seams and not perforated, will keep humid air on the
> warm side, preventing condensation. Also, since no metal skin is
> totally airtight, any small amount of moisture should find it's way out
> the seams of the metal panels.
Oh, are the seams of the metal panels vertical or horizontal (lapped)?
If vertical, you'll need a moisture-resistand sheet behind the metal
panel, flashed to the exterior. This would be helpful too, even if the
siding is horizontally lapped.
v
wrote:
>On Tue, 14 Aug 2001 07:53:17 -0400, Walt <Wa...@Early.com> some motley
>fool wrote:
>
>>Check your local building codes. You may not be allowed to
>>have exposed insulation in an area which is deemed to be
>>inhabitable.
>>
>Of course you can. That's the place you CAN have it.
MEA CULPA MEA CULPA.
I misread the word inhabitableas uninhabitable.
-v.
Eric
barrier to the metal skin inside the building as well as to the warm side of
the framing? What does 'flashed to the exterior' mean?
"TW" <nov...@erols.com> wrote in message news:3B7D1B4F...@erols.com...
TW
>
> They're vertical. So I would have to apply the same type of moisture
> barrier to the metal skin inside the building as well as to the warm side of
> the framing?
No. The barrier on the INSIDE must be a "vapor barrier", which stops
passage of water vapor (humidity). Aluminum foil is a vapor barrier. A
"vapor barrier" is nor necessarily waterproof. The exterior barrier is
WATER resistant. Tyvec and 15 lb. asphalt felts are each a water
resistant barrier, but not vapor-proof. It is placed and lapped like
shingles to prevent and liquid water that has passed through the
exterior wall finish (Siding, shingles, stucco, etc.) from reaching your
insulation and studs. This moisture-resistant sheet (Tyvec, 15 lb. felt)
should NOT be a vapor barrier, because if it were, it would prevent
moisture in the insulation/stud space from evaporating out of the wall.
> What does 'flashed to the exterior' mean?
This is where you may have a problem regardless of all the posts so far,
because you are essentially building a wall from the inside out rather
than from the outside in. Seeing the wall in person is very important
to solving this problem. If your panels do leak at all, it is necessary
to install a membrane (usually metal "flashing") at the bottom of the
inside of the wall panels to direct such water back OUT the wall to the
exterior. (This possible leakage problem is why some posters
recommended venting the "space" from between your insulation and the
wall panels.) Flashing is placed vertically over the last 6 or so of
the bottom (exterior face) of the stud wall (here a hard substrate is
helpful), and runs under the panels to the outside. It's bent down on
outside to form a "drip". The vertical inside end of the flashing is
covered (lapped) by the water-resistant membrane.
Eric
building is pretty tight. The vertical steel wall panels are screwed to an
L shaped beam 2 inches on each side, which is bolted to the foundation. The
gaps in the panels are filled with some hard substance up to the 2 inch side
of the L shaped beam. There doesn't appear to be any water penetration at
the moment. However, in one section of the building, it appears that water
may have come in via the outside sprinkler system a few years back since the
L shaped beam is slightly corroded. Besides, it would be difficult to
install flashing since the bottom of the panels are inaccessible from the
interior due to the L shaped beam. This beam goes all around the
foundation's first 2 inches and is how they secured the vertical panels. I
may apply some spray foam to this area before framing to reduce future water
intrusions.
Eric
"TW" <nov...@erols.com> wrote in message news:3B7FB5CE...@erols.com...
Larry Caldwell
Er...@nospam.com writes:
> What this sounds like is that I have to place a sheathing on the frame on
> the side facing the metal wall prior to raising it and securing it to the
> foundation. Then, after electric and other routings are completed, I can
> insulate it with fiberglass batts, add a moisture barrier, and then
> sheetrock.
Have you thought about rigid insulation? Bead board comes in 6"
thickness. Then you could nail girts to the inside of the posts and rock
the girts. Styrofoam is a trademark, and a little more expensive. It
comes in all sorts of interlocking styles and widths. Foil faced
urethane is another option.
Eric
haven't heard any good news regarding their exposure in the case of a fire.
Seems they spew out some pretty noxious fumes. I think I've decided to go
ahead with framing the interior of the metal building with 2x10s and R-30
insulation. I've heard different posts regarding the use of 2x6s for R-30,
but since R-30 is almost 10'' wide, it only makes sense to use 2x10s. Of
course they're more expensive, but so is the insulation.
"Larry Caldwell" <lar...@teleport.com> wrote in message
news:MPG.15f2c345f...@news.teleport.com...
Larry Caldwell
> I've thought about it. It would definitely save square footage. However, I
> haven't heard any good news regarding their exposure in the case of a fire.
> Seems they spew out some pretty noxious fumes. I think I've decided to go
> ahead with framing the interior of the metal building with 2x10s and R-30
> insulation. I've heard different posts regarding the use of 2x6s for R-30,
> but since R-30 is almost 10'' wide, it only makes sense to use 2x10s. Of
> course they're more expensive, but so is the insulation.
That's a waste of lumber. Just frame it with 2x4's and block off to the
outside of the building every 8' or so. If you are building to code you
have to add solid fireblocking in the whole cavity every 10' anyway.
Filling the space with lumber serves no purpose at all. If you were
planning on friction fitting unfaced batt, that's a lousy design. The
first rat that climbs it will destroy your insulation.
I still think rigid board is your best option. The fumes thing is a red
herring, unless you plan on sitting in the building while it burns down
around you.
Eric
get R-30 in walls? Besides, to me, the amount of lumber I use is immaterial
since the cost isn't that much more. I'll lose 2 inches due to the lintels,
and an additional 6 inches due to the steel horizontal beams. That's eight
inches already. I want to conceal the beams, so adding a few more inches
won't break the bank, will increase the insulation, and will make the place
more livable.
"Larry Caldwell" <lar...@teleport.com> wrote in message
news:MPG.15f754e2...@news.teleport.com...
Larry Caldwell
Er...@nospam.com writes:
> The plan is to use 'faced' insulation. No waste of lumber. How else do you
> get R-30 in walls?
You don't need 2x10 to hang 10" of insulation. There is no point to
filling the cavity with wood.
Eric
completely within studs to provide the maximum R value. As R-30 is 9 1/2''
thick, how do you get around this? I was thinking of going with 2x6's and
have the insulation extend for another 3 1/2'' until someone pointed this
out. What's your opinion on this? I know that laying unfaced batts of
insulation in the ceiling doesn't have such requirements and am not
completely sure why one needs to have the batts completely enclosed within
the studs. Someone even suggested stapling Tyvec to the outside of the
studs to completely seal the insulation within the walls.
"Larry Caldwell" <lar...@teleport.com> wrote in message
news:MPG.15f8b8c48...@news.teleport.com...
Larry Caldwell
Er...@nospam.com writes:
> I've heard in this newsgroup that the insulation needs to be 'contained'
> completely within studs to provide the maximum R value. As R-30 is 9 1/2''
> thick, how do you get around this? I was thinking of going with 2x6's and
> have the insulation extend for another 3 1/2'' until someone pointed this
> out. What's your opinion on this? I know that laying unfaced batts of
> insulation in the ceiling doesn't have such requirements and am not
> completely sure why one needs to have the batts completely enclosed within
> the studs. Someone even suggested stapling Tyvec to the outside of the
> studs to completely seal the insulation within the walls.
I don't think it's a question of how thick it is, but how wide. If you
frame on 2' centers, you have a 22.5" space between studs. Some
insulation hardly fills the space, other brands will have plenty of fluff
to pick up the extra 3/4" as it exits the back of the stud.
The rule with insulation is to seal the warm side and vent the cool side,
which keeps moisture from condensing in the middle of the batt. Of
course, warm side is defined in winter. You don't care about moisture
when it's so hot you could fry an egg on the sheet metal. So just use
the insulation facing and let the ribs on the metal vent the back side.
Matthew S. Whiting
>
> I've heard in this newsgroup that the insulation needs to be 'contained'
> completely within studs to provide the maximum R value. As R-30 is 9 1/2''
> thick, how do you get around this? I was thinking of going with 2x6's and
> have the insulation extend for another 3 1/2'' until someone pointed this
> out. What's your opinion on this? I know that laying unfaced batts of
> insulation in the ceiling doesn't have such requirements and am not
> completely sure why one needs to have the batts completely enclosed within
> the studs. Someone even suggested stapling Tyvec to the outside of the
> studs to completely seal the insulation within the walls.
I don't see why the insulation cares if it is contained in the cavity.
It'll insulate much the same as long as you have a vapor barrier on the
inside to prevent air infiltration.
The way you get around it, is to use 2x10 studs! If you are going to
have walls that thick with insulation anyway, why not have the studs
that deep? More cost, but probably not that much more. Also, if you
now decide to sheath the inside walls you'll have something to nail to.
Matt
Dan Hicks
face is left open, since this allows air to circulate through the
fiberglass, resulting in convective losses. This happens when unfaced
fiberglass is used in attic -- it loses maybe 1/3 of its insulating
value.
--
Dan Hicks
A man does not have to be an angel in order to be saint. --Albert
Schweitzer
Eric
side to contain the R-30 insulation. Larry pointed out that if using 24''
oc, that would mean 22 1/2'' space between the studs. The faced R-30 batts
I've seen at stores come in 24'' widths. That's sqeezing it by 3/4'' on
each side. Hopefully that won't degrade the R value by much.
"Dan Hicks" <danh...@ieee.org> wrote in message
news:3B902691...@ieee.org...
Dan Hicks
fact, it might even increase the R value a tad.
--
Dan Hicks
Heisenberg may have slept here.
Matthew S. Whiting
>
> Thanks Dan. I'm back to the idea of using 2x10s with tyvec on the exterior
> side to contain the R-30 insulation. Larry pointed out that if using 24''
> oc, that would mean 22 1/2'' space between the studs. The faced R-30 batts
> I've seen at stores come in 24'' widths. That's sqeezing it by 3/4'' on
> each side. Hopefully that won't degrade the R value by much.
That's funny as around here 23" is the standard. Leaves just a little
compression. Same thing for 16" stud spacing, the insulation is
typically 15".
Matt