My ground floor slab is a lot like a raft, floating on a sea of insulation. It will be completely isolated from the ambient climate and will help keep my occupants cozy/warm in the wintertime and cool/collected in the summertime.
If you study this photo (above) you’ll get a better sense of how this all comes together. Clockwise, from top left:
1. Evan’s backside. He’s laying a section of blue foam (XPS Type VII). You’ll notice this foam running around the edge of the raft and down its middle. Through this layer of blue foam the interior load bearing walls will spread their structural load to the compacted soil below.
2. Foam lip. Just to the right of Evan you’ll notice an upturned section of white foam (low density EPS Type I). This will be the thermal break between raft/slab and perimeter frost wall.
3. Stego wrap. The bright yellow sheet is the first section of air/vapor barrier that will further isolate my interior from the great outdoors. Every pipe penetration through it is sealed tight with handmade boots fashioned out of sticky red tape and squares of wrap cut to the diameter of each pipe.
The wrap will be partially sandwiched between layers of foam and will turn up and over the perimeter frost wall. Once my walls start going up it will tie into their air-tight sheathing.
4. Butter knife. Down at the bottom of the photo is a bundle of white foam boards that are used under most of the slab (EPS Type I), sitting next to a band saw. The saw, when it comes to cutting unwieldy foam, is like a warm knife is to butter.
5. Kevin’s backside. Just to the left of the saw. He’s picking up small bits of debris that would otherwise interfere with the arduous task of creating an amazingly effective raft/slab.