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I want to insulate the outside of my house and I'd like to know which type of insulation you think is best.

Anonymous Nov. 15, 2017, 10:34 a.m.

I live in Southern Alberta and will be replacing my exterior vinyl siding with wood, I also want to add insulation at the same time. It's a 2x4 wall with pink insulation and a vapour barrier behind the drywall,  and only vinyl on the outside. There are a lot of different kinds of foam and I don't want to choose the wrong one, which do you recommend and how much will I need? Thanks, Michael. 

Responses (5)

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Dave King Jan. 4, 2019, 1:13 p.m. Reply

Hi,

We have purchased a 2 season non insulated 2 story summer home that has a 2X4 frame and no insulation. At all. The exterior cedar siding keeps it nice and dry, but with winter at -30C / -22F, we want to make it a 4 season getaway.

We love the painted, open frame interieur look (we can see all the 2X4's) and have decided all work must be on the outside.

We thought about 6" or 8" steel studes on the outside with blown foam insulation to fill in and stopp all air leaks. We would then put new cedar siding on the outside.

Will this work, and what should we modify to make it work?

Thanks

Ecohome Jan. 7, 2019, 11:04 a.m. Reply

 

Hi Dave, 

 The biggest modification I'd suggest would be to ditch the steel. So much heat would be conducted through the metal that it would reduce the effectiveness of the insulation you install by an easy 25% and likely more, read more about that in the link at the bottom.

What you are describing could likely be done with wooden I-joists, though I'd consult an engineer to make sure that the foundation is solid as well as the framed load-bearing walls before you make any modifications. As for spray foam, there are two companies that we know of who have switched to much less harmful blowing agents - Demilec and Elastochem.

You could also swap out the foam for cellulose, that would be cheaper than the spray foam, though there are additional durability concerns so you'd need to ensure there is no water infiltration. 

And here is a link to a product that may be a more simple solution, it is a foam panel with a metal rail embedded in the center that is used to attach it to the wall and that the stapping is then attached to for installing siding. You would just screw it to the wall, then screw strapping to the same panel for installing future siding. 

And one part that will need careful design is the wall-to-roof junction. If the walls aren't insulated then most likely the ceiling isn't either. You may be able to blow insulation into the attic if it has one, or if it is a vaulted ceiling you may also be able to continue whatever wall system you decide on. Definetly have it designed by a professional to ensure not just efficiency, but durabily as well. Without existing insulation it's much less worrisom, but you always need to be careful when drastically changing a wall system to not invite new problems from moisture buildup. 

Here are some other pages that may be worth a read before you get started:

 

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