My SIPs building is going up and we are having intermitent rain. We've kept the panels as dry as possible and they are going together pretty well, but they have unavaidably gotten some moisture.With winter coming (here in Alaska) I'm worried about the moisture getting out of the panels and chases before we seal it up. Surely other people have built with SIPS and got caught in the rain, can I get some suggestions of how to deal with this? Somebody told me that since the SIPS tape goes on the INSIDE moisture will exfiltrate. Although our temps are getting cooler 50's during the day high 30's low 40's at night but we ARE getting a good deal of wind and the structure is in a locationg that catches it. Would it help to put off installing the windows as long as possible?

I would roll on a coat of water base polyurethane sealer, it will keep the water & moisture from penetrating and will not degrade the EPS if it comes in contact

OK well actually my question is about steps to take after the walls and roof have been rained on prior to shingles and siding. It's raining there now and the roof is going on Monday(?) I hope

Posted By haese56 on 23 Sep 2012 08:12 PM
OK well actually my question is about steps to take after the walls and roof have been rained on prior to shingles and siding. It's raining there now and the roof is going on Monday(?) I hope

Don't they come treated with a temporary moisture resistant coating?

I would for sure let them dry out prior to putting the shingles and siding on.

Being that you are in rain belt Alaska. I hope you are venting those roof wood SIPS:

Posted By haese56 on 23 Sep 2012 08:12 PM
OK well actually my question is about steps to take after the walls and roof have been rained on prior to shingles and siding. It's raining there now and the roof is going on Monday(?) I hope

haese56,
it is one of the reasons I got away from OSB, once they get wet they will start to swell and be hard to get together, but if it is already assembled, then no problem.
Cover with 15# felt or any good building wrap on the walls and 30# felt or peel n stick membrane on the roof
Your supplier should have some specific guidlines to follow?

Posted By Lbear on 24 Sep 2012 12:46 AM

Posted By haese56 on 23 Sep 2012 08:12 PM
OK well actually my question is about steps to take after the walls and roof have been rained on prior to shingles and siding. It's raining there now and the roof is going on Monday(?) I hope

Don't they come treated with a temporary moisture resistant coating?

I would for sure let them dry out prior to putting the shingles and siding on.

Being that you are in rain belt Alaska. I hope you are venting those roof wood SIPS:

I see that "building science" is recommending a membrane or .019 metal on the interior ridge.
seems like a lot of extra work.

Posted By cmkavala on 24 Sep 2012 06:08 AM


I see that "building science" is recommending a membrane or .019 metal on the interior ridge.
seems like a lot of extra work.

Alaska is where the whole "SIP roof rot" thing started. I agree, it is a lot of work. Too much of a risk if it is not done, as replacing a rotted SIP roof will cost an insane amount of money. Cheaper to do a cold roof now.

Or one could do it in a steel SIP but that point is moot with the OP.