Ice and Water Shield On Porch?
Bgreer5050
IWS? Should I flash the siding to roof with IWS? Thanks.
http://mropartner.com/frontelevation.htm
marson
IMO, ice and water in this location is unnecessary. I would flash the
siding with coil stock/step flashings. Ice and water doesn't really
work because none of it can be exposed. If you expect extreme wind
driven rain, you might consider it as an insurance layer under your
flashing (lapped up under your building paper). I would use ice and
water on eaves in valleys in climates with snow, and under asphalt
shingles applied to a pitch less than 3/12.
hal...@aol.com
yes because the extra cost will be low
inspect...@gmail.com
1507.8.3 Underlayment.
Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869. In
areas where there has been a history of ice forming along the eaves
causing a backup of water, an ice barrier that consists of at least
two layers of underlayment cemented together or of a self-adhering
polymer-modified bitumen sheet shall be used in lieu of normal
underlayment and extend from the eave's edge to a point at least 24
inches (610 mm) inside the exterior wall line of the building.
Yes, ice and water shield (or equivalent) should be used if there is a
history of freezing temperatures and it should extend BEYOND the
exterior wall to OVER the interior of the structure 24" min. This is
also the standard used by most shingle manufacturers and warranties
may be voided if not installed.
JMHO
Terry
inspect...@gmail.com
Sorry wrong reference... IBC 1507.2.8.2 Ice dam membrane... verbatim
inspect...@gmail.com
Sorry, wrong reference... See
IBC 1507.2.8.2 Ice dam membrane.
In areas where there has been a history of ice forming along the eaves
causing a backup of water, a membrane that consists of at least two
layers of underlayment cemented together or of a self-adhering polymer
Larry
<inspect...@gmail.com> wrote
>> 1507.8.3 Underlayment.
>> Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869. In
>> areas where there has been a history of ice forming along the eaves
>> causing a backup of water, an ice barrier that consists of at least
>> two layers of underlayment cemented together or of a self-adhering
>> polymer-modified bitumen sheet shall be used in lieu of normal
>> underlayment and extend from the eave's edge to a point at least 24
>> inches (610 mm) inside the exterior wall line of the building.
>>
>> Yes, ice and water shield (or equivalent) should be used if there is a
>> history of freezing temperatures and it should extend BEYOND the
>> exterior wall to OVER the interior of the structure 24" min. This is
>> also the standard used by most shingle manufacturers and warranties
>> may be voided if not installed.
>>
>> JMHO
>>
>> Terry
>
> Sorry wrong reference... IBC 1507.2.8.2 Ice dam membrane... verbatim
Well inspector, you should have noticed, this is an _unheated_ area in
question.
So much for being an inspector.
marson
Ice dams occur because heat from the interior of a building melts
snow, and the resulting water runs onto the eave, where it freezes,
since the eave is no longer heated from the interior of the building.
The resulting ice dam causes water to back up under the shingles, and
preventing the resultant leaks is the function of the ice and water
shield, and this is why codes require it. So I guess the question is,
will ice dams form on your unheated porch? I've never seen it happen,
even in climates that get a lot of snow (300+ inches).
Bgreer5050
"marson" <brian...@gmail.com> wrote in message
news:1179705660.1...@a26g2000pre.googlegroups.com...
3D Peruna
>
> Ice dams occur because heat from the interior of a building melts
> snow, and the resulting water runs onto the eave, where it freezes,
> since the eave is no longer heated from the interior of the building.
> The resulting ice dam causes water to back up under the shingles, and
> preventing the resultant leaks is the function of the ice and water
> shield, and this is why codes require it. So I guess the question is,
> will ice dams form on your unheated porch? I've never seen it happen,
> even in climates that get a lot of snow (300+ inches).
Yes. It can happen. It's not always a function of heated/unheated
spaces. Often, the melting occurs due to sun/warm temperatures. For
instance, it's on an east exposure, it will warm on a sunny day, melt,
then as the sun moves west, it re-freezes. This causes an ice damn to
build over a period of several days.
People often want to blame faulty construction (not enough insulation,
etc), when it's simply a microclimate issue that the designer didn't
think about.
inspect...@gmail.com
> spaces. Often, the melting occurs due to sun/warm temperatures. For
> instance, it's on an east exposure, it will warm on a sunny day, melt,
> then as the sun moves west, it re-freezes. This causes an ice damn to
> build over a period of several days.
>
> People often want to blame faulty construction (not enough insulation,
> etc), when it's simply a microclimate issue that the designer didn't
> think about.
This is true and is the reason for the code requirement.
There is no exception within the codes for roofs over unheated
porches, only for detached unheated structures.
I DIDNT WRITE THE CODE... i just enforce it within my jurisdiction.
Terry
Larry
<inspect...@gmail.com> wrote
> This is true and is the reason for the code requirement.
>
> There is no exception within the codes for roofs over unheated
> porches, only for detached unheated structures.
>
> I DIDNT WRITE THE CODE... i just enforce it within my jurisdiction.
I call BS. It's not possible to comply with the code you cited, for this
structure's porch.
Tell us exactly how one would get to a point 24" inside the exterior wall
line of the building.
Sorry, your really have _no_ clue on how to interpret this code.
inspect...@gmail.com
> structure's porch.
> Tell us exactly how one would get to a point 24" inside the exterior wall
> line of the building.
>
> Sorry, your really have _no_ clue on how to interpret this code.
>
> 1507.8.3 Underlayment.
> Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869. In
> areas where there has been a history of ice forming along the eaves
> causing a backup of water, an ice barrier that consists of at least
> two layers of underlayment cemented together or of a self-adhering
> polymer-modified bitumen sheet shall be used in lieu of normal
> underlayment and extend from the eave's edge to a point at least 24
> inches (610 mm) inside the exterior wall line of the building.
This particular item does not require extending beyond the wall line.
I included that because a lot of installer do not realize that
extension is required and the intent is to have Ice and Water Shield
where damming is possible. This situation is why the code has
multiple sections. We must design and build as close to the letter
AND the intent of the code as possible, not forgetting real
situational constraints. We also must understand that ALL conditions
can not be addressed in a single book, and that meeting the Code
Minimum is equal to passing high school with a D-.
1507.2.9 Flashings.
Flashing for asphalt shingles shall comply with this section. Flashing
shall be applied in accordance with this section and the asphalt
shingle manufacturer's printed instructions.
Dennis
snow, runs down to the gutter and re-freezes night. It can be a very real
cause of ice damming; not just heat loss from the structure.
I also would not hesitate to use IWS underlayment. Cost is low and excellent
insurance. (I used it 100% on my roof.) It's not a code requirement in this
particular area, but it's good common sense to add extra insurance at little
extra cost. (I'm also an inspector / plan reviewer as well.)
Larry
<inspect...@gmail.com> wrote in message
news:1179936086....@u30g2000hsc.googlegroups.com...
>> 1507.8.3 Underlayment.
>> Underlayment shall comply with ASTM D 226, Type I or ASTM D 4869. In
>> areas where there has been a history of ice forming along the eaves
>> causing a backup of water, an ice barrier that consists of at least
>> two layers of underlayment cemented together or of a self-adhering
>> polymer-modified bitumen sheet shall be used in lieu of normal
>> underlayment and extend from the eave's edge to a point at least 24
>> inches (610 mm) inside the exterior wall line of the building.
>
> This particular item does not require extending beyond the wall line.
> I included that because a lot of installer do not realize that
> extension is required and the intent is to have Ice and Water Shield
> where damming is possible. This situation is why the code has
> multiple sections. We must design and build as close to the letter
> AND the intent of the code as possible, not forgetting real
> situational constraints. We also must understand that ALL conditions
> can not be addressed in a single book, and that meeting the Code
> Minimum is equal to passing high school with a D-.
>
> 1507.2.9 Flashings.
> Flashing for asphalt shingles shall comply with this section. Flashing
> shall be applied in accordance with this section and the asphalt
> shingle manufacturer's printed instructions.
You would not make it in a real city. I don't want to be rude, but you're
better off sticking to a small town in Utah. By stating absurd remarks such
as " Minimum is equal to passing high school with a D-", I highly doubt you
get paid funds by any city or state. You are putting emotions above the
job. Is it any wonder you are asking in different groups attempting to keep
up to date with codes? Real inspection jobs pay for continuing education,
be it private industry, or working for uncle Sam. Just try telling a
contractor, you red tagged the work because it meets minimum.
You're skirting the code issue, _you_ brought up, by citing a totally
different code for flashings. Please further address what was being
discussed. In fact, the code _you_ cited, specifically states "In areas
where there has been a history, blah, blah". Being this is, what appears to
be new construction, there isn't a history. Plus, this is an unheated area,
and w&i shield can not be applied in the way, this code cites.
There's a reason why I'm calling you on this. I did contract work for roof
inspections, in 4 larger cities, all in 1 county. The area was in the
Midwest, where temperatures fluctuate widely.
BTW, I'm not against water & ice shield. In fact, I would prefer to see it
used as if every deck surface was heated.
On second thought, please do not address this issue any further. You really
don't know what you're talking about, so why should I waste my time,
proving you don't?
Don
> inspector.terry> wrote
>> and that meeting the Code
>> Minimum is equal to passing high school with a D-.
>>
> school with a D-",
You're right, that is absurd.
It should be F, for *False Sense Of Security* that codes offer to ignorant
home purchasers.
After all, look at who requires them.
marson
Well you can spend 30 bucks a square on I&W if you want. That isn't a
insignificant cost to me. Yes unheated roofs might get a bit of ice
on the eaves. But I have never, ever seen a leak from an ice dam on
an unheated roof. Never. Have you seen a leak?
celt...@aol.com
Why not? I think the expense would be minimal. Even if the
ppotential for damage from ice-damming would be minimal, the possible
cost could be quite high. At worst, it would probably serve as
another layer against leaks.
benick
"Larry" <No...@invalid.com> wrote in message
news:4654debd$0$1390$4c36...@roadrunner.com...
the whole building with Ice and Water Shield and still sometimes get leaks
from wind driven rain off the water even on unheated porches and
garages...You would be surprised where water gets driven by a 60 MPH
gale.....LOL
>
>
marson
> "Larry" <N...@invalid.com> wrote in message
>
> news:4654debd$0$1390$4c36...@roadrunner.com...
>
>
>
> > <inspector.te...@gmail.com> wrote in message
And therefore, if you live in Minneapolis MN, you should ice and water
the whole roof because of conditions in Maine? LOL!
Michael Bulatovich
> And therefore, if you live in Minneapolis MN, you should ice and water
> the whole roof because of conditions in Maine? LOL!
Context is everything.
benick
No moron . My point was it depends on where you live NOT just "The Codes"
The codes don't require the whole building to be covered here BUT
EXPERIENCED contractors know to take LOCAL CONDITIONS(waterfront,direction
of exposure, ect.)into account. Last I checked MN has about 10,000 lakes as
well as big open fields and wind driven rain..I typed slow so maybe you
could follow along.
>
marson
> "marson" <briankon...@gmail.com> wrote in message
Well, call me a moron if you want. I don't get involved in flame
wars. We were having a discussion about ice and water shield as
protection against leaks caused by ice damming and whether an unheated
porch requires it. You bust in and say that because of wind driven
rain in maine, we should be using ice and water on unheated porches.
That just doesn't make sense. It's like me busting into a discussion
about protecting a structure from termites in Mississippi and saying
that the footings should be 54" deep cause that's how we do it in
Minnesota.
I have worked for people who wanted ice and water over their whole
roof. Sure doesn't hurt, but at 30 bucks a square, it's not exactly
cheap. Again, I just have not seen leaks on roofs. I've seen leaks
from ice dams, and leaks from bad flashing, but on a big simple roof
with adequate pitch, I just haven't ever seen leaks. Now if you live
somewhere where conditions are extreme then by all means use ice and
water instead of tarpaper.
Larry
"Don" wrote
> You're right, that is absurd.
> It should be F, for *False Sense Of Security* that codes offer to
> ignorant home purchasers.
> After all, look at who requires them.
So, codes are just relevant to residential dwellings. Where do you live?
Don
As far as I'm concerned they are completely irrelevent.
> Where do you live?
Here, I'll make this easy for you Larry.
I have been involved in over 7,000 projects in an area with some of the
toughest *builing codes* in the country and ya know what?
I mainly ignore them.
Ya see, when you design large scale custom residences on islands that are
routinely subjected to Cat3 to Cat5 conditions there is no way in hell a
thinking person would trust any stupid assed gov't ruling with their clients
property and lives or their own reputation.
People that tout building codes are silly and not meant to be taken
seriously.
Onward.................
Larry
"Don" wrote
> Here, I'll make this easy for you Larry.
> I have been involved in over 7,000 projects in an area with some of the
> toughest *builing codes* in the country and ya know what?
> I mainly ignore them.
>
> Ya see, when you design large scale custom residences on islands that are
> routinely subjected to Cat3 to Cat5 conditions there is no way in hell a
> thinking person would trust any stupid assed gov't ruling with their
> clients property and lives or their own reputation.
Ohhhhh Don, you must be the new net super hero. I'm so impressed!
Custom residences yet! Wow! Surely you're the only one in existence which
designs a custom home in the Cat5 territory.
And, a tough guy at that.
Can I please have your autograph?
Don
In fact, in that area, I AM the only one doing the designing.
> And, a tough guy at that.
>
> Can I please have your autograph?
Awww, did I hurt little larry's silly nerve? LOL
Fucking crybaby.........
benick
Moron
I don't get involved in flame
> wars.
you just did
We were having a discussion about ice and water shield as
> protection against leaks caused by ice damming and whether an unheated
> porch requires it.
So was I
You bust in
Didn't realize this was a privite discussion
and say that because of wind driven
> rain in maine
Didn't realize wind driven rain was exclusive to Maine
, we should be using ice and water on unheated porches.
Yep sometimes
> That just doesn't make sense.
I'll try to type slower
It's like me busting into a discussion
> about protecting a structure from termites in Mississippi and saying
> that the footings should be 54" deep cause that's how we do it in
> Minnesota.
HUH??? MORON
>
> I have worked for people who wanted ice and water over their whole
> roof. Sure doesn't hurt, but at 30 bucks a square, it's not exactly
> cheap.
As compared to what??Paying for water damage
Again, I just have not seen leaks on roofs. I've seen leaks
> from ice dams, and leaks from bad flashing, but on a big simple roof
> with adequate pitch, I just haven't ever seen leaks.
Big SIMPLE roof??? Do they build them that way anymore???lol
Dormer,skylights and funky valleys seem to be the norm .
Now if you live
> somewhere where conditions are extreme then by all means use ice and
> water instead of tarpaper.
I'm glad we finally agree....
>
Dennis
>You bust in and say that because of wind driven
> rain in maine, we should be using ice and water on unheated porches.
> That just doesn't make sense. It's like me busting into a discussion
Ice dams are not just the products of heat leaking through roofs. The sun
can (and does) cause ice dams every year on my patio cover (open under.)
While the ice and water backs up, it's no big deal because it's just an open
patio cover. Point is, if it's your own home, the use of self-adhering
underlayment is simply a good & inexpensive investment. (And if you think
that underlayment is expensive, you probably can't aford to build or
remodel. Protection of the structure is paramount in consideration.
>Again, I just have not seen leaks on roofs. I've seen leaks
> from ice dams, and leaks from bad flashing, but on a big simple roof
All asphalt roof will eventually leak. It's only a question of time before
the shingles deteriorate to a point where they will.
Even new roofs can leak in a storm. As one responder mentioned, in Maine,
they use the self-adhering type on a regular basis based on experience.
As it's not a big expense, I would recommend it's use on all roofs (if you
never want to worry about leaks. Perhaps it's over kill in many cases, but
sometimes peace of mind it worth a little extra.)
And if you still want to argue about the expense, I'd hate to talk to you
about tile floors or granite countertops. <chuckle>
Don
> As it's not a big expense, I would recommend it's use on all roofs (if you
> never want to worry about leaks. Perhaps it's over kill in many cases, but
> sometimes peace of mind it worth a little extra.)
>
> And if you still want to argue about the expense, I'd hate to talk to you
> about tile floors or granite countertops. <chuckle>
Indeed.
If the budget is tight then you can always install granite later when the
coin is right.
When trimming costs the last place you want to do so is in the very part of
the house that protects all the others, the roof.
marson
Well, I don't know how they are doing things in your part of the
country. I live in a town of about 100,000. Since I moved here a few
years ago, I have personally supervised 10's of roofs, and have
observed probably 100's of reroofs and roofs going on new
construction. Every one I have seen gets Ice and water on the eaves
and valleys and felt everywhere else. These roofs are working. Why
fix what isn't broke? I don't get it. The cost of construction here
is out of this world, and adding $1000 to $1500 to the cost of a roof
just isn't justified.
Don
$1500?
You need to find a new supplier.
Just because it didn't *break* in the 'few years' you've been living there
means nothing about leaks that may occur eventually.
Curious, did you ask the homeowners if their roofs leak, as its hard to tell
if a roof is leaking while *observing* it from the curb?
marson
> "marson" <briankon...@gmail.com> wrote in message
First of all, the stuff ranges from 25 to 50 bucks a square for the
material. Last I checked, it isn't climbing the ladder and rolling
itself out spontaneously. You're going to have to add some labor for
the installation. If you are in an area where it isn't being used
typically, a roofer is going to charge a premium for the
installation. If you have a big house, it's going to cost you MORE
than 1500.
Why do you think the installation instructions don't call for putting
it on the whole roof? http://www.gaf.com/Content/Documents/20002.pdf
You'd think the manufacturer would want you to cover your whole house
inside and out with two layers if they thought it was a good idea.
Explain that one.
Dennis
face is $36/sq. (and that's retail).
As far as labor, it would be only a little more, considering you would have
to roll out and fasten down use 15# underlayment anyway. (At least if your
building to code).
If your only installing cheap asphalt shingle roofs (20 year), I would agree
that it's use may be questionable as the roof is probably only going to be
good for 15 years anyway. But for longer-life products (including 30-40 year
asphalt, tile and the like), it's a no-brainier to use it.
For a quality home, a roof is not a place to go cheap.
marson
And why aren't manufacturers recommending this? They'd sell more
product.
The answer is probably two fold: it has little or no value in
practice, and second, ice and water shield is a vapor barrier, and
unless your ventilation is good, you could wind up with rotted roof
sheathing.
This is not a standard practice. It is not being done in most parts
of the country. Go out and look at some roofs, talk to some roofers
and contractors.
Don
> At our local Menards, the poly face is $34/sq. (3'x33') and the granular
> face is $36/sq. (and that's retail).
Coincidently I priced it at Menards in Columbus, IN today and they told me
$36 for a 3' x 100' roll, granular.
Don
> And why aren't manufacturers recommending this? They'd sell more
> product.
How do you know they aren't?
Cause they haven't recommended it to you?
> The answer is probably two fold: it has little or no value in
> practice, and second, ice and water shield is a vapor barrier, and
> unless your ventilation is good, you could wind up with rotted roof
> sheathing.
If a person is *building in accordance with codes* he then has proper
ventilation, right?
> This is not a standard practice. It is not being done in most parts
> of the country.
LOL, *most parts*, huh?
Man, you cover a lot of territory.LOL
Go out and look at some roofs, talk to some roofers
> and contractors.
*Most* contractors are cheapskates.
Its best to get advice from people that have no stake in it.
Robert Allison
> At our local Menards, the poly face is $34/sq. (3'x33') and the granular
> face is $36/sq. (and that's retail).
> As far as labor, it would be only a little more, considering you would have
> to roll out and fasten down use 15# underlayment anyway. (At least if your
> building to code).
>
> If your only installing cheap asphalt shingle roofs (20 year), I would agree
> that it's use may be questionable as the roof is probably only going to be
> good for 15 years anyway. But for longer-life products (including 30-40 year
> asphalt, tile and the like), it's a no-brainier to use it.
> For a quality home, a roof is not a place to go cheap.
If you think that the roof is important, then you should also
consider your plumbing. Although, like placing IWS
everywhere, it is not common practice, placing all of your
plumbing pipes in PVC can keep that possible leak from
becoming a disaster. I have seen many more homes destroyed or
damaged by plumbing leaks than roof leaks. And I should know
as I am in the insurance repair business (15 years or so).
It is simple (like using IWS everywhere). Simply install 2"
PVC pipe everywhere that you need water, then run your copper
or PEX through the PVC. Should there be a leak, the PVC
contains it.
And hey, what about fire? It would probably be a good idea to
encase all of your combustable materials in concrete. That
way, there is nothing to catch fire except your personal
property and that could be treated with a fire retardant.
Don't forget about these other things and just add ICW.
Remember, a little extra goes a long way to protect your
quality home. Whats a few extra tens of thousands of dollars
when your peace of mind is at stake?
>>First of all, the stuff ranges from 25 to 50 bucks a square for the
>>material. Last I checked, it isn't climbing the ladder and rolling
>>itself out spontaneously. You're going to have to add some labor for
>>the installation. If you are in an area where it isn't being used
>
>
>
--
Robert Allison
Rimshot, Inc.
Georgetown, TX
Don
> If you think that the roof is important, then you should also consider
> your plumbing. Although, like placing IWS everywhere, it is not common
> practice, placing all of your plumbing pipes in PVC can keep that possible
> leak from becoming a disaster. I have seen many more homes destroyed or
> damaged by plumbing leaks than roof leaks. And I should know as I am in
> the insurance repair business (15 years or so).
>
> It is simple (like using IWS everywhere). Simply install 2" PVC pipe
> everywhere that you need water, then run your copper or PEX through the
> PVC. Should there be a leak, the PVC contains it.
>
> And hey, what about fire? It would probably be a good idea to encase all
> of your combustable materials in concrete. That way, there is nothing to
> catch fire except your personal property and that could be treated with a
> fire retardant.
>
> Don't forget about these other things and just add ICW. Remember, a little
> extra goes a long way to protect your quality home. Whats a few extra
> tens of thousands of dollars when your peace of mind is at stake?
Ya know, if you tack another $10k to the overall price for the
infrastructure and $5k for the schools (do it for the *children*) you'll be
close to describing a typical SW Florida home.
The kind that no one can afford.
marson
> "marson"> wrote
>
> > And why aren't manufacturers recommending this? They'd sell more
> > product.
>
> How do you know they aren't?
> Cause they haven't recommended it to you?
Read the package instructions.
marson
Yep, and my roofer refuses to use the shit from menards because by the
time you fix all the tears etc, you would have been better off
spending a few more bucks.
Don
LOL, uh, OK, if you say so.
Don
The thing about buying stuff at Menards/Lowes/Home Depot, etc. is that the
choosing of products is the sole responsibility of the purchaser.
I sort of prefer that myself.
Just yesterday I purchased about $400 worth of PT lumber and anchor bolts
and various other things for a project I'm building and I *hand selcted*
every single component to assure that I received the best they had.
If your roofer spent time fixing tears and stuff you should have planted
your workboot squarely in his ass for wasting your time and resources.
A few minutes spent up front scrutinizing the purchases saves alot of
problems on down the line.
Quality builders know this, why don't you?
marson
> "marson" <briankon...@gmail.com> wrote in message
Gotcha there. http://www.gaf.com/Content/Documents/20002.pdf .
Dennis
> product.
Manufacturers are manufacturing this product, like all products they sell to
a specific market / end use. This product was designed to comply with a
specific code requirement, as an alternate to two layers of underlayment,
cemented together. It saves time and labor; money in other words.
However, that's the code, and most prescriptive codes are designed as
minimums and are usually exceeded when there is a good reason to do so. The
reason that the manufacturers do not state that it is to be used everywhere
is simple, whatever they put on the package is considered a requirement,
legally binding in court. Any local building official would then be
permitted to make a full installation mandatory. As there is no need to
overbuild anything, there is no need to make such practice a recommendation.
> The answer is probably two fold: it has little or no value in
> practice, and second, ice and water shield is a vapor barrier, and
> unless your ventilation is good, you could wind up with rotted roof
> sheathing.
You're worng on both points. First it has obovious value in offering
additional protection to a roof deck. Only a fool would argue that overkill
has no value. Second, although it does have a specific requirement of 0.01
perms max. it should never cause a roof deck to rot. (Do you think that
standard Type I underlayment overlaid with two thicknesses of asphault
shingles wont retard the passage of water vapor?) Ventilations in al attics
is a must (and a code requiremtnt). The most likely pace you will every find
a rotted deck is low down, near the eaves. Upon investigation we find that
there was little or no air circulation, often that the insulation had been
blown into the area and in contact with the bottom of the roof deck. Proper
ventialltion, and not just the minimums required by the IRC, is an absolute
must. (It's also off topic).
> This is not a standard practice. It is not being done in most parts
> of the country. Go out and look at some roofs, talk to some roofers
> and contractors.
As an inspector (my current position is plan reviewer), I have inspected
hundreds of installations. I have found that roofers vary in their
knowledge, but those highly concerned with doing an outstanding job that
they can be proud of, to those who are looking forward to collecting their
paycheck and getting drunk that evening. (Like any trade). Some even argues
that they didn't need to use underlayment. Many didn't know the proper way
to build a valley and a few could not explain what a stepped flashing was or
what the requirements for it were.
I do agree that it's not standard practice, as most of the public either has
no idea as to what constitutes a good roof verses an outstanding one; and
they will always opt for the lowest price. It's use is really for those who
are building a higher-end home, usually with permanent clay-tile roofs or
long-life asphalt or the like. For the average low-end market, installing
ice-shield at the eaves with regular Type-I underlayment over the rest of
the roof is the only way to maintain competitively and low price.
This by no means ensures that the owner will be getting the best for his
money (for only a modest amount more he could be getting many more years of
roof life compared to the minimum materials). You simply quote minimum code
to get the job and then offer to upgrade the materials (labor will be pretty
much the same in all cases).
The argument isn't whether is costs more or not (it does) or whether is
common practice or not (it isn't). The argument is that it makes a better
roof (longevity and greater leak resistance, especially in high wind zones)
verses one covered with standard Type-I underlayment. (It does).
Michael Bulatovich
"Dennis" <webm...@npcc.net> wrote in message
news:_ZV7i.4$fX4.2@trndny03...
>> And why aren't manufacturers recommending this? They'd sell more
>> product.
>
> Manufacturers are manufacturing this product, like all products they sell
> to a specific market / end use. This product was designed to comply with a
> specific code requirement, as an alternate to two layers of underlayment,
> cemented together. It saves time and labor; money in other words.
>
> However, that's the code, and most prescriptive codes are designed as
> minimums and are usually exceeded when there is a good reason to do so.
> The reason that the manufacturers do not state that it is to be used
> everywhere is simple, whatever they put on the package is considered a
> requirement, legally binding in court. Any local building official would
> then be permitted to make a full installation mandatory.
That's just not true. Some building officials are power-mad bureaucrats.
>> The answer is probably two fold: it has little or no value in
>> practice, and second, ice and water shield is a vapor barrier, and
>> unless your ventilation is good, you could wind up with rotted roof
>> sheathing.
>
> You're worng on both points. First it has obovious value in offering
> additional protection to a roof deck. Only a fool would argue that
> overkill has no value.
That's plain silly. "Overkill" needn't always be benign. Look at bolt
tortion, for a simple example. Ever heard of "too much of a good thing?"
marson
> legally binding in court. Any local building official would then be
> permitted to make a full installation mandatory. As there is no need to
> overbuild anything, there is no need to make such practice a recommendation.
>
>
If this is true, then why do they include hips, ridges, and rakes in
their instructions? Ice and water shield on ridges and rakes is not
code in my state. But you are saying that it is considered a
requirement, legally binding in court because GAF puts it on their
instructions?
Regarding ventilation, in the case of new construction, you are
probably right. But it is highly irresponsible to be recommending ice
and water shield over the whole roof to everyone. Lots of old houses
have roofs that are marginally ventilated and have marginal vapor
barriers, as you must know.
marson
marginal vapor barrier on the warm side of the house insulation to be
exact.
Bgreer5050
"marson" <brian...@gmail.com> wrote in message
news:1179680262.8...@x18g2000prd.googlegroups.com...
> On May 20, 11:34 am, "Bgreer5050" <bgreer5...@yahoo.com> wrote:
>> Please take a look at the elevation below. Should the entire porch have
>> IWS? Should I flash the siding to roof with IWS? Thanks.
>>
>> http://mropartner.com/frontelevation.htm
>
> IMO, ice and water in this location is unnecessary. I would flash the
> siding with coil stock/step flashings. Ice and water doesn't really
> work because none of it can be exposed. If you expect extreme wind
> driven rain, you might consider it as an insurance layer under your
> flashing (lapped up under your building paper). I would use ice and
> water on eaves in valleys in climates with snow, and under asphalt
> shingles applied to a pitch less than 3/12.
>
