Water and Ice Shield on entire roof, bad idea?

[BeachBoy]

Re: Water and Ice Shield on entire roof, bad idea?

Here is what Grace has to say about Grace Ice & Water Shield:

"Grace Ice & Water Shield offers premium leak protection for sloped roofs in climates subject to ice dams and wind-driven rain. It is applied to the roof deck prior to the application of the finished roof covering, which is most often shingles but can also be tile or metal. The membrane goes under shingles and seals around nails that hold the shingles in place, so water that doesn't drain properly cannot penetrate the roof. It also creates a weather-tight barrier against wind-driven rains that cause shingles to lift and leak. Affordable and easy to install, it provides added peace of mind for many years, even in the most brutal winters."

Key points: Seals around nails. Keeps water that shouldn't be there (whatever the reason) from penetrating roof. Barrier to wind driven rain.

That is why you might want to use it on the entire roof. For when the unexpected happens.

Link:

http://www.graceathome.com/pages/roofingprod3.htm

[Kye GC]

Re: Water and Ice Shield on entire roof, bad idea?

The big questions are where are you, what is the slope of the roof, and what type of roofing will cover it.

If your say in VT with a low 4/12 pitched comp shingled roof I'd sure insist on it. If your in an area with a low pitched roof that gets wind blown rain, it's also not a bad idea. Standing seam, no worries, any bitch under roofing in the southwest=bad idea. It all depends.

Kye

[Dick Seibert]

Re: Water and Ice Shield on entire roof, bad idea?

The reason I put I&W under tile and slate is that I built under a lot of oak trees, the organic material rotted out the #30 felt when people didn't keep the leaves cleaned off. We did some jobs where we not only laid #30 down on the deck, but also interlaced it shake-style between the tile, in some cases it not only rotted out the interlaced paper, but got to the paper on the deck after 30 years.

[BigLou80]

Re: Water and Ice Shield on entire roof, bad idea?

I like Frank have worked on many roofs with no underlayment and no leaking. Its just not necessary with a properly installed roof and flashings.
A slate roof should be installed with enough head lap to prevent even wind driven rain from being an issue, and 99% of slate roofs won't hold snow long enough for ice dams to form. slate should also be installed on boards not plywood but that another thread but at any rate its just not worth doing.

Allan,
you like overkill. don't you double wrap your sidewalls with felt and tyvek ? It proves the point "cost does not create value", but as long as it sells your houses all the more power to you.

Beach Boy,
Grace will say what it takes to sell more of thier product.It may be some value in wind driven rain, where no shingles blow off,. If you have shingles blowing off at least some of the nail will go with them. Grace may seal around nails but it can't fill the whole where nails once were. If shingles are blowing off a roof leak is probably the least of your worries.

Dick,
I have no experiance with tile,its just not used here in new england. But how can leaves on top of the roof cause the underlayment to rot ? I guess anything is possible but that sounds like a stretch

Lou

[parkwest]

Re: Water and Ice Shield on entire roof, bad idea?

What does the shingle manufacture recommend be placed under it's shingle product? Thats what I think should be done to reduce your exposure to a liability claim.

[Dick Seibert]

Re: Water and Ice Shield on entire roof, bad idea?

Kye:

I've had situations where oak leaves and pine needles have worked their way down between the tiles and the decaying organic material rotted out the felt, felt is organic you know. I had a bad case where moss grew on one side of the roof, growing down to the felt and rotting it out.

[wirerat99]

Re: Water and Ice Shield on entire roof, bad idea?

If it helps I'm in central virginia, 10/12 roof, with dementional shingles. thanks for all the help

[Kye GC]

Re: Water and Ice Shield on entire roof, bad idea?

Sounds like overkill to me but if the gc want's it and is paying you to do it, hey, why not. When I'm asked to do something that doesn't really benefit the project but doesn't hurt it either, I usually politely give my two cents and move on in whatever direction the HO or gc want's to go in.

On that roof in your area, as long as the roof is properly vented, the bituthane shouldn't be a problem.

Kye

[Housewright]

Re: Water and Ice Shield on entire roof, bad idea?

We've done it on a couple jobs where we needed a quick, secure dry-in. I can tell you the non-granulated versions are pretty damn slippery. The sub that does our copper roofing is always behind schedule getting to the job. So organic felt would never hold up. His work is excellent so we don't mind waiting. He likes us to dry in with GAF storm guard. Not all the bituthanes are approved under metal roofs, check with the manufacturer. He then lays a slip-sheet when he installs the copper pans.

[fpopjr]

Re: Water and Ice Shield on entire roof, bad idea?

would anyone here completly cover a medium pitch unvented roof, either sips or open/closed cell spray foam, with grace ice & water?

[tommyboy]

Re: Water and Ice Shield on entire roof, bad idea?

I would recommend going in the exact opposite direction. Put grace in the valleys and deck-armor by gaf on the roof. We've been working with this stuff and it is nice. Allows the sheathing to breath, very water tight and rolls out flat as a pancake. With a 10/12 pitch, a monkey could install shingles that won't leak.

[Graacc1]

Re: Water and Ice Shield on entire roof, bad idea?

I just recently asked Grace about this. The situation was a slate roof on a 120 yr. old brick firehouse, currently used for dead storage by the town, I think one small room is heated but not the whole building. GC wanted to weathertight the roof (after stripping off old slates) because he needed masonry work done along the roof rakes and mason couldn't get there for a 2 weeks. Grace said NOT a good idea, but check with area rep. Rep. says not a good idea, BUT, under the circumstances and IF the roof is properly vented it would be acceptable, but again NOT recommended.
I would NOT I&W the whole roof, but use it on the eaves and valleys, use some of the new underlays for the rest of the roof OR get a WRITTEN waiver of liability from the GC to you against leakeage claims if you do cover the roof with I&W.
Geoff

[Dick Seibert]

Re: Water and Ice Shield on entire roof, bad idea?

It's strange that Grace would say that, not that I disbelieve you, they promote it on their website, the only caveat is to use Grace Ultra in hot areas, the reps here told me that I don't need Ultra, they only recommend it in the Southwest and mountain areas because of UV rays.

[gdavis]

Re: Water and Ice Shield on entire roof, bad idea?

My response to this question has always been "absolutely not" because of my concern for trapping moisture. Today, I'm not real sure that it is a valid concern.

But then again, If you are using plywood or OSB sheathing, the roof is already pretty impermeable except for the joints. So I'm not sure that it is really going to hurt that much, and in areas where workmanship on shingles is questionable it might be a good trade off to make sure that no water gets in at the risk of trapping a little moisture.

Bottom line, I don't really think it would make that much difference. So if it helps your marketing position use it. If it doesn't save your money.
but personally, I'd air on the side of caution. Sometimes you can attempt to do better and get accused of causing a problem because you didn't do it the way everyone else does it.

g

[stevenboston]

Re: Water and Ice Shield on entire roof, bad idea?

Ah this makes sense for a situation I had...low pitch roof where we ice and water shielded the whole thing. Humidity was building up in the attic and moisture meters on the decking underside always were high in the winter. Never thought about the stuff being a VB but it makes sense. Once we added more ventilation the problem went away but I can now vouch that it did create a moisture issue.