Footings are poured! Things are moving now. Builder promised to caulk underneath the framed walls, and the OSB to the studs. Seems like a good start.

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Posted By BadgerBoilerMN on 04 Oct 2016 11:02 AM
This is the standard in N. America for sub-slab insulation.

http://www.menards.com/main/building-materials/insulation/insulation-panels/f250-2-x-4-x-8-r-10-extruded-polystyrene-insulation/p-1444450504310-c-5779.htm?tid=-9197785561416543961

Anyone else have any suggestions for underslab? This stuff is almost a buck a sq. ft. Would love to find something lower cost if possible. I've been trying to find used/reclaimed without any luck so far, but I need to get it pretty soon.

We buy EPS for less than half that. Look at commercial roofing outlets like ABC, Beacon Sales etc.

Posted By rgonyer on 24 Oct 2016 11:03 AM
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That is a LOT of corners & bump-outs, which will increase your framing fraction to well over 25%, maybe even more than 30%. that makes it harder to air seal too, especially at the non-perpendicular corners.

The high framing fraction would make exterior foam an even more signficant performance improvement than on a house with 8 or fewer corners (A "T" topology or simpler.)

Coming together - Great!

I would use sill seal under your bottom plate instead of caulk.

foam sill seal is junk; it does not seal. Use these EDPM construction gaskets, which run about $1/lf: http://www.conservationtechnology.com/building_gaskets.html

Instead of caulking the sheathing, you might enjoy a product such as "ecoseal" which is applied within the inside of the stud bays and along the sill plates with a high pressure airless sprayer. If you search youtube for "ecoseal", you will find demonstrations on how it penetrates into the cracks. If you're persistent about using a caulking product, I've learned from the chatter on this board and GBA that you should be sure to use a high quality polyurethane caulk and not your typical paint-on low quality caulk.
I am enjoying this thread as I will be building next year or the year following.

I wonder how many people using caulk/sealant even know what "3 sided adhesion" is or why a bond breaker is necessary in a fillet joint.

Maybe 1 in 20, and of those, myself included, half or better ignore those rules most of the time. You really gonna make a tiny bond break at a floor to tub intersection? Backer rod is at least easy, corner bond break not so much in smaller residential joints.

http://www.conservationtechnology.com/

It worked for me & I cut & pasted it.

http://www.conservationtechnology.com/

It worked for me & I cut & pasted it.