Hi everyone, I am about to build a new home in Toronto. I would like this home to be as airtight as possible (I'm tired of living in my current drafty / thinly insulated uncomfortable old home). I have been consuming as much information as I can about insulation (spray foam, SIPS, ICF, etc.). Due to build requirements, it looks like the best way for us to frame the home will be the old stick frame method. Unfortunately there is also a termite problem in Toronto so we need to take this into consideration. My questions are many ... but to start: 1. If we stick frame the home, would it make the most sense to just spray foam the inner walls and then we are done? The spray foam would also act as a vapor barrier and the bricks are simply attached to the outside wood sheathing? Is that right? 2. If we use XPS on the entire exterior, would we also require insulation on the side walls? (It seems like this would be doubling up if by using sprayfoam we could simply do the entire interior and be done with it?) 3. What is the best way to insulate the basement to be as airtight as possible all the while not leaving it susceptible to termites? I understand termites will burrow in XPS or sprayfoam? 4. Finally, it seems to me that using blown insulation in the attic is a waste of space. Ideally my home will not have an attic (the architect is working on that now), but if it is necessary, can't we just sprayfoam the bottom of the roof and use the attic as a storage area? Lastly - can anyone recommend someone (of course, I'm happy to pay for the service) that can take a look at my architectural drawings and specify exactly what insulation to use and how to apply it to the building? This would be great - as I could simply provide it to my builder and quote it out. My experience here in Toronto (we are in a very hot market) is that builders simply build cheap and fast. I'm finding it difficult to find someone that will even consider sprayfoam. Everyone is fixated on old bat insulation. Any help is appreciated. As you can see, I'm quite out of my element and just want to make sure I will have an excellent green end-result.

I designed my own home, 1921 farm house gutted to the sticks, and foamed the 2x4 roof rafters to an R-50 (hot roof). Though I wouldn't put anything in an attic but mechanicals.

Steel studs are thermally superior to wood. In new construction I like Thermax on over 1/2" OSB of plywood to stop thermal bridging. After that the R-value depends on the wall system with spray-foam, glass or cellulose being the most popular. Basements should be insulated from without and stone wool seems to be the trend here in Minneapolis.

We don't have many termite problems but if we did:

http://www.tais-lb.com/?page_id=22

http://www.roxul.com/files/RX-NA_EN/pdf/ComfortBoard%20IS.pdf

We use Manual 'J' software to model insulation and window systems to better evaluate our mechanical designs and give people realistic ROI numbers.

I know Dana will be right back to smother us with numbers...

For stick frame, it's usually hard to beat the price/performance of cellulose filled walls + EPS foam (either side) to reduce thermal bridging. With care, you can air seal quite well without using spray foam. It's best if vapor permeability on the exterior side is several times higher than on the interior side. If not, make sure that the external foam is thick enough for your climate.

We also use a lot of Optima in our deep renovation work since it will generally stay drier and burn less.

"Steel studs are thermally superior to wood. In new construction I"

PLEASE GIVE THE SOURCE!!!

It's simply not true for All the steel studs I've seen, even the supposedly "thermally broken ones.

Posted By jonr on 18 Jun 2014 11:26 PM
For stick frame, it's usually hard to beat the price/performance of cellulose filled walls + EPS foam (either side) to reduce thermal bridging. With care, you can air seal quite well without using spray foam. It's best if vapor permeability on the exterior side is several times higher than on the interior side. If not, make sure that the external foam is thick enough for your climate.

Hopefully this is not too far off topic....  Is there a general rule of thumb or guideline as to whether 2x12 (offset 2x4) with dense pack cellulose is "better" (cheaper? easier? more effective?) than 2x6 with cellulose plus rigid foam?

cellulose is one contractor, one job, one set of details; cellulose and foam are two. The second is more expensive due to the additional labor of installing the foam, but the material costs are similar using EPS. The foam is a better thermal break and less likely to have condensation issues, provided the R value is sufficient for the climate. Either is a potential failure point in a home where air leakage or proper insulation design are done poorly. A thick wall is a great place for mold to grow.

bricks are simply attached to the outside wood sheathing?

There should be a gap between them and then a wrap or foam.

Ok - I see this is over my head now. Can anyone recommend someone (preferably in Toronto) that can take my architectural plans and come up with an insulating plan?

look at the websites for passiveHouse US (PHIUS), Passive House Alliance, and any other PH sites that come up and look for architects or designers who do that type of building. And they don't have to be Toronto. Mike at http://www.deapgroup.com/Services.html has consulted on a number of homes and is an excellent resource.