Why are "Ice and Water" roof membranes always "peel-and-stick" ???

[Joe]

Roofers I've talked to say that re-roofing a house that had an ice and water membrane put on it 10 or 15 years ago is a pain. Ripping the old membrane off frequently leads to replacing parts of the plywood deck.

I don't understand why these Ice and Water membranes have to be "peel and stick". Seems they would work just fine if you rolled them out and put a few nails on them to keep them in place before the shingles go down (ie same as tar paper).

Does anyone make an Ice and Water membrane that's NOT peel and stick? (Tamko Nail Fast seems like it but Tamko doesn't exactly call it an Ice and Water shield even though it's made of the same SBS material).

[Tom]

Joe wrote:>

Here I go again! A properly insulated and ventilated attic and properly installed roof system doesn't need any of that stuff. Building codes for your area could possibly spec some type of underlayment to extend at least 3 feet beyond the inside walls of the house, or even the entire deck. Depending on the pitch, the sticky stuff can be dangerous enough for a roofer to walk on, moreso with just a few nails holding it on. Tom Work at your leisure!

[kevwalsh]

Well I guess that is just end of discussion, huh?

In reality, many of us have roofs that have, well, less than ideal designs. Mine is 50 years old, rather flimsy, cape-cod style. Many existing roofs are very hard to insulate and ventilate properly. Due to cost, historic building restriction, aesthetics, and many other reasons, many of us just have to find a way to keep our houses leak-free, despite a poorly designed roof system. It is always an uphill battle, of course.

Tarpaper is next to useless when it comes to ice and water buildup. I'd personally love some ice-and-water peel and stick on our roof. When we redo, we'll put some down. Nails will leak sooner than adhesive. You really want something that is water proof, not just something that uses gravity to direct water down the roof. Our house, for instance, can get ice dams (if we are not very attentive, and let things go) about 10" to 14" thick, which leads to a pool of water as much as several feet back from the edge. This will submerge the nailed edge of whatever you have down, and leak. The sticky tape will do a better job, hopefully.

[Tom]

kevwalsh wrote:>In reality, many of us have roofs that have, well, less than ideal

I'm betting "cost" is the major restriction to a proper roof, especially to the builder. Historic building restrictions? Would that apply to the attic insulation, too? I'd love an historic roof, especially cedar shingles over scabboards. Of course, it doesn't get very close to ice dam situations here in Southern AZ, at my altitude. How do you attend to your ice dams to keep 'em down? I've chopped at them, but it's dicey. Too easy to damage the shingles. Tom Work at your leisure!

[L. M. Rappaport]

On 15 Oct 2004 18:38:52 GMT, [e-mail] (Tom) wrote (with possible editing):

Well, I respectfully disagree. If that were so, then ice dams wouldn't form on unheated buildings and they do. Not being an expert, I can only guess that it's got to do with the color of the roof, the pitch and its direction, along with the amount of direct sunlight to which the roof is exposed.

[L. M. Rappaport]

On 14 Oct 2004 22:25:48 -0700, [e-mail] (Joe) wrote (with possible editing):

Just a suggestion from an amateur: perhaps you could leave the paper backing on? (never tried it)

We used Grace Ice and Water Shield over the entire roof along with shingles guaranteed for 30 years. We did this because even though the roof is properly insulated and vented with proper vent, soffit and ridge vents, we have eyeballs (recessed lights) in the cathedral ceilings and found that the heat from them was enough to melt snow above them which would run down a bit and then freeze. Eventually this would cause ice dams, pooling, etc. and water would leak between the sheathing and the finished ceiling. Of course, if I had it to do over again, I wouldn't use eyeballs.

[Joe]

I see my main point (or question) has been missed.

Some here are arguing that you don't need any sort of advanced underlayment under the shingles - even over the eaves where flowing water can freeze and/or back up and get under the shingles on low-slope roofs. If you feel that ice/water membranes are a gimic or aren't needed, fine. You don't have to follow this thread.

For those (like me) that think an ice/water membrane (as opposed to tar paper) is the smart thing to put over the eaves, all I'm wondering is why the membrane has to be peel-and-stick instead of just being nailed down. It is the FUTURE situation of dealing with the membrane being stuck to the deck that I'm wonding about (and apparently IS causing problems in re-roofing situations).

Look. They used to "glue" 2 sheets of 15-lb felt tar paper together and use that over the eaves. But even in that case the resulting sheet was never "glued" to the wood deck - it was nailed.

Again, it's NOT the membrane (water-impervious-ness) that I'm questioning. I just don't see why it has to have an adhesive surface and become essentially glued to the plywood deck. If it was just nailed down, with the shingles put on top, then I don't see how water would EVER get under the membrane and contact the wood.

[Joe]

I've been told that the first membrane sheets that came out for Ice/Water had a smooth top side (10 to 15 years ago). That's why you're seeing smooth membranes now in re-roofing jobs because your seeing these original membrane sheets.

The membranes now are coated (sanded, granular) and I think it's because roofers were slipping on the smooth membranes so the granules make it non-slip. These have been available for maybe 10 years now and the odd job is coming across these membranes.

I don't buy the argument that the granules are there to be able to un-roll it (the peel-away backing will prevent it sticking while rolled up). In theory, the granules serve NO purpose to help the membrane shed water and actually make it hard for the shingles to bond to the membrane when the granules are in the way of making a good bond.

It is said that the asphalt (in the membrane) softens when heated and migrates around the granules and adheres to the underside of the shingles. Why go through all that hassle? Seems the granules are more trouble than they're worth if you need this heating/asphalt migration thing to happen.

So basically the use of a granular-top-coated peel-and-stick IS a pain in the butt when it comes to re-roofing and that you can't tear off old shingles WITHOUT ripping the membrane to hell (yes?) and even more

- that you can expect to destroy or pull up the wood decking. Seems like a VERY high price to pay - and I'm not sure what the benefit is (to using THAT kind of membrane).

If I understand this correctly:

If you put on a granular-top-coated peel-and-stick membrane now, then in 15 or 20 years (when you need to re-roof) that:

(1) the shinges won't release easily from the membrane (because the membrane NEEDS an asphalt layer to flow through the granules and bond to the underside of the shingles!)

(2) the membrane won't release easily from the deck

(3) you've essentially got a sandwitch of shingles/membrane/deck that can't be separated without lots of effort and destruction of the surface of the wood deck so much so that it becomes more cost effective to rip the plywood deck off and replace.

Have I got that right?

If so, then the solution is

(a) use a membrane with a smooth top surface with no asphalt layer to become permanently bonded to the shingles (does anyone make such a membrane ?)

(b) use a membrane (with a granular top layer or not) but without a peel-and-stick bottom side (so that you can rip it off later without messing up the wood deck). Again, does anyone make a NON peel-and-stick membrane? (seems not).

(c) use a peel-and-stick membrane BUT leave the release sheet on. Unroll the membrane and nail it down. Then in 10 or 15 years it will come off easily.

I'm thinking that accidents, law suits, and product liability issues have played a LARGE role in the design of the currently-available ice/water membranes.

Think about it - peel-and-stick underside, granular coated top side - both serve basically ONE purpose - to prevent the roofer from sliping and falling off the roof. Neither the adhesive underside or the granular coated top side help AT ALL in helping the membrane perform it's function of preventing water that gets under the shingles from making contact with the wood deck.

However, both the peel-and-stick bottom side and granular/asphalt-coated top side are a MAJOR pain when it comes to re-roofing.

Comments?

[Tom]

Joe wrote:>Think about it - peel-and-stick underside, granular coated top side

-

Correct, Joe. Only for the relative safety of the roofer (Which I thought I'd covered in my original reply to the OP, BTW). The membrane doesn't NEED to be stuck down to the deck to perform it's function, but only to the drip edge and any neighboring pieces of i&w shield. You can get away with a 3 inch lap. And yes, it's hell to tear off old i&w shield. Tom Work at your leisure!

[diane]

Ok, my stupid question: couldn't one just stick a new layer of the same stuff over the old (assuming the old isn't all torn up)? Just wondering since I'm planning to use some of this under my concrete roof tile...

[Joe]

My shingles are going up next week (IKO Chateau).

The installer knows I'm concerned about the "peel-and-stick" part of the membrane installation. I'm probably going to have to replace quite a bit of the old eave decking as it is (and they charge $$$ for doing it). It would piss me off to think that the peel-and-stick part of the membrane will mean the investment in the new decking will be lost when the wood gets torn up in 20 years when I re-roof.

Should I stick to my guns and tell them to leave the release membrane ON and nail the membrane down?

[Tom]

Joe wrote: >Should I stick to my guns and tell them to leave the release membrane

The roofers might find that to be a PITA, especially if they need to traverse it often. And it'll still need to be adhered at the edges. I say skip the I&W shield, and a good 30# felting will do. Tom Work at your leisure!

[John Hines]

No, let them do the job right. IMHO from watching the roofers on Monday, the peel and stick is more for holding it down during the install. It was kinda unweildy for them, until it was stuck down, then it was like part of the decking, as the underlayment and shingles were installed.

The next re-roof should be another layer of shingles, without a tear off, so you shouldn't have to tear it off for 30-40 years, at which time the shield has done its job, and the roof needs to be torn down to the sheathing, for inspection and repair.

[Eric Tonks]

[Tom]

John wrote:>

Yabbut, his first layer will be a dimensional roof, very convoluted compared to your typical 3-tab. They don't usually take well to a roof-over. Also, the problem with the I&W shield sticking to the decking(then trying to tear it off

20 years from now) is the OP's main beef. Tom Work at your leisure!

[Joe]

So tell me why nailing down felt is somehow not a problem, but try to suggest nailing down the Ice/Water membrane and all of a sudden it's a different story. ???

And why does I/W needs to be adhered to the edges, when felt doesn't (because it can't)? If felt doesn't have a peel-and-stick backing, and if you'd suggest it in place of I/W, then why can't I get away with nailing I/W and NOT using it's sticky part?

In other words, just because the I/W membrane has a sticky backing why does that mean I have to USE the sticky backing? The I/W membrane is a membrane NOT BECAUSE OF THE STICKY BACKING. It's special because of what it's made of - not because it has a sticky backing. The sticky backing does not make it work better. I think the membrane part is great! I think the sticky backing is for SHIT because of what it means for re-roofing later.

I'll bet it takes less time to take an I/W membrane, LEAVE THE RELEASE SHEET ON, unroll it and position it, and then nail it. Vs taking the release sheet off and wrestling with it while it's all sticky and trying to get it into position. Come on - nailing it down should be no more difficult than if it was felt.

Yes- these are single-tab shingles, and I'm looking at a weight of 300 lbs per square (vs 215 lbs for your average 3-tab).

Yes. I guess it wouldn't be so bad if in 20 years when I take the shingles off that they release easily from the I/W shield so that basically the shield could stay put on the roof and I just throw new shingles over them. But if the shield needs to come off, then I SHOULDN'T HAVE TO TEAR UP THE PLYWOOD when I'm at it.

I have yet to hear a clear technical reason why these I/W membranes have a sticky underside that essentially glues them to the wood deck. They don't need that in order to act as an I/W membrane to keep water from getting to the deck by backing up under the shingles.

All I can imagine (and hear some people observing) that the sticky part of these I/W membranes are bad news when it comes time to re-roof. Lots of down-side to the sticky back-side, and no up-side.

I'm thinking the sticky backside is all for product liability reasons and not for technical / performance reasons.

[Joe]

Your old I/W shield probably had a smooth top surface.

The kind they use today have a granular top surface.

Does anyone have any observations of roofers laying new I/W shield over top of old GRANULAR I/W ???

Again, I think that both the sticky underside and the granular top side of these membranes is only for product liability. Any roofer walking on a properly applied granular-top-coated I/W membrane will have plenty of grip.

That's nice if you make these membranes, and I'm sure it's nice for roofers working on the high-sloped mansions that are all the rage now aday's, but it means SQUAT for the low-slope home owner that has to deal with tearing the hell out of his decking in 20 years because of friggin sticky-back membrane. (!)

[3D Peruna]

The purpose of an I/W membrane is to keep out the ice dams which often GROW from the bottom up. If you don't have the membrane adhered to the substrate, the ice can grow between the substrate and the membrane, making the whole thing useless. Even with proper drip flashing, this could be a problem. With the adhered membrane, you can't get any water between it and the substrate, thus making it an effective system. Nailing it down is as effective as having felt.

[PAUL100]

I beleive the sticky backing does need to be there. on the front edge of the roof it seals itself to the edge of the plywood to prevent any water or ice from getting to the wood. with out it being sticky. water or ice could easily get under it at the edge

[Tom]

Joe wrote:>

Well, what did I tell you the first time you broached this subject? It helps keep the roofer from falling off the roof. Tom Work at your leisure!