Air and moisture proofing
Dave B| Posted inEnergy Efficiency and Durabilityon
I am going to be renovating a 1950’s house in Toronto, ON. It’s a 1 ½ storey that we are making 2 storey with adding addition on the back and attached garage. The plan for the 2nd storey is wrap the outside in Blueskin then cover in 3” Roxul Comfortboard IS, Strap and vinyl side. 3 of the 1st floor brick walls are to be left in place, which I also want to cover in 3” Roxul strap and vinyl side, but unsure what to use under it to keep the air and moisture out. Should I wrap the house in OSB (may help in attaching strapping) then Blueskin .Is there any other products or ideas to seal my brick house up???? Thanks
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Replies
Dave,
The type of work you are contemplating will be challenging. Especially tricky: the window flashing details.
Assuming that you can come up with a plan to handle your windows, I think that you may find the work less challenging if you use rigid foam rather than mineral wool. Mineral wool compresses somewhat when furring strips are screwed through the insulation, complicating the work.
Another option is to simply call up an EIFS contractor, who does this type of work all the time.
The windows I was thinking of using a plywood box extensions, I have also looked at Roxul site and there recommended install "Punched Window Interface – Installation Sequence". of course that's for the addition area not the existing brick walls. I was hoping to stay with Roxul because of the Canadian connection and Eco- friendliness, when compared to foam. I have some concern about the compression of 3" Comfortboard IS but figure there are people that do it???
I was looking for some recommended air & water sealers for the brick walls, so to make it air and water tight as possible. Thanks
It isn't clear, but it sounds like you plan to cover the brick with insulation, then strapping, then vinyl siding. Is that right? If so, you don't need to seal the brick. If you plan to keep the brick on the exterior, understand that brick needs to be able to let moisture pass through it. Sealing it with a waterproof product will create a risk that moisture (from leaks, water vapour from inside, or ?) will get trapped inside the waterproof coating, freeze and spall the brick. You want to seal it with something that lets water vapour through, but keeps out bulk water. You want something that works like Goretex, not a rubber raincoat.
Dave,
Following up on Stephen's advice, you could consider coating the exterior of your brick walls with a liquid-applied WRB. These products are vapor-permeable.
For more information on these products, seeHousewrap in a Can: Liquid-Applied WRBs.