Ice and Water Shield On Porch?

[Bgreer5050]

Please take a look at the elevation below. Should the entire porch have IWS? Should I flash the siding to roof with IWS? Thanks.

[inspector.terry]

The IBC states the following:

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

[inspector.terry]

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 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.

[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).

[3D Peruna]

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.

[inspector.terry]

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]

wrote

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.

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.

[inspector.terry]

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.

[Larry]

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?

[benick]

Well you would BOTH be wrong here on the Maine coast we dam near cover 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]

And therefore, if you live in Minneapolis MN, you should ice and water the whole roof because of conditions in Maine? LOL!

[Michael Bulatovich]

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]

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

So, codes are just relevant to residential dwellings. Where do you live?

[Don]

"Larry"> wrote

As far as I'm concerned they are completely irrelevent.

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

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.

Awww, did I hurt little larry's silly nerve? LOL Fucking crybaby.........

[benick]

Moron

I don't get involved in flame

you just did

We were having a discussion about ice and water shield as

So was I

You bust in

Didn't realize this was a privite discussion

and say that because of wind driven

Didn't realize wind driven rain was exclusive to Maine

, we should be using ice and water on unheated porches.

Yep sometimes

I'll try to type slower

It's like me busting into a discussion

HUH??? MORON

As compared to what??Paying for water damage

Again, I just have not seen leaks on roofs. I've 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

I'm glad we finally agree....

>

[Dennis]

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.

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.