Hi - I'm building a cabin/cottage in Northern Ontario. The building is on steel stilts and will be exposed to the elements from beneath the structure. Half the building will cantilever over a rockformation. We are planning on using 10.25" SIPs for floor and roof with a flat metal roof system. Also plan on using an in-floor hydronic radiant heating system as primary heat source. With below 0F temperatures in the winter - does this sound adequate or will my family freeze in the winter. I've talked to builders that have used 12.5" SIPs in the Northeast. Any thoughts?

A 4' x 8' panel if it is a 12.5" should only be about $10 more than a 10.15" panel. I would do the math. On one hand, piece of mind, but if could be a couple grand more is your plan calls for a couple of hundred panels. I always recommend the super insulate. Especially in the northern climates of New Mexico, sometimes it snows!

I would love to know how much you increase the R-value of the cantilevered floor by having infloor heating. It has got to help tremendously. On the roof, I would not even consider the lesser of the two. It might be a good compromise to use the 10 1/4" in the wall and 12 1/2" in the roof. The other critical decision will be ERV or HRV. We have more use for an ERV here, but then again when it snows we close the schools...

Thanks for the insights Greg. I will price out the 10.15 vs. the 12.5 but it sounds like the investment may be worthwhile in my climate.

justin_toronto,

It seems an EPS foam core SIP is most common in the wood SIP industry. They typically have about an R4 per inch of thickness. If you could find a PU/PIR (polyurethane modified polyisocyanurate) foam core SIP it would have about a R7.5 per inch. This type of SIP is more efficient in cold climates.

Justin_Toronto

We manufacture sip's floor panels, send us your plan or a sketch and we will give you our opinion

Pierre

[email protected]

thanks for the info Jeff - I'll look into this option