Off gassing/smell of Ice and Water shield through tongue and groove into building?
I’m building a cottage in climate zone 7 (NW Ontario). The roof is single-pitch, unvented, 2:12 slope. I used much of the advise from this website to help with my decision making.
The stackup from inside to out will be:
Rafters (exposed to interior)
T+G (exposed to interior)
I+W
Rigid foam board
Roof decking
I+W
Standing seam or snap lock metal
The roof is not completely assembled yet. I chose the 1st layer of I+W because I needed to ensure the roof was weather tight over the winter so a peel and stick was ideal.
However I’ve been reading that in this situation, some people experience issues with smell or off-gassing from the I+W.
I’m hoping to hear if this is really an issue, as I’d much rather fix it now than late, if you catch my drift. I dislike throwing away money and materials, but I want to make sure it’s done right, and that we will not be exposed to any lingering nasty smells.
Note we are a good two years away from occupancy, so if the smell is a time bound thing that would be good to know too.
I’m not sure if this is just a hot weather issue, and if my cooler zone 7 makes a difference.
Any insight would be appreciated!
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Replies
I don't have data points one way or another for your scenario, but you could perhaps consider products that are not asphaltic for that first layer. Because the inboard layer is not the true roof deck, I would even consider non-underlayment (i.e. just WRB) peel and stick membranes as potential options.
I would not attempt to pull it up at this point. Even if you do you are probably going to leave some behind and if it was going to smell it will still. I think under your insulation it’s a lot less likely to be an issue. FWIW I usually spec something like proclima adhero or if it’s a short exposure time vp100 (this will not hold up for long as roof wrb).
You read this slightly differently than I did, so now I think explicit confirmation is warranted.
To the original poster: Is the first layer already installed? If so, what is the specific product used?
HI Patrick - yes the I+W was installed in the fall, the rest of the roof assembly will go up this spring/summer.
Chris,
Purely anecdotally, I haven't found I&WS to smell when it isn't hot. Rolls stored in my shed don't smell. Rolls in the back seat of my pickup don't either unless the sun hits them.
I find it sometimes smells a bit when you first unroll it, and/or when you first peel it just prior to sticking it down. I've never found it to smell after installation, and certainly not enough to notice from inside. I've always noticed the smell of hot new asphalt shingles more than the the ice and water shield.
Bill
I have this roof stackup and it has never smelled, at all. I do not have 100 percent I&W but a fair bit. I think that if you have an uninsulated roof deck and go in the attic, that very hot material might smell
That is the commentary I was hoping for. Seems like I'll leave it, but I'll conduct a little test myself once I get out there after snow melt just to be sure.
I appreciate the help, all. Thanks for taking the time to reply.