Garage Conversion, crawlspace question

gawngulfing

In our Wisconsin ranch home we will be converting the current garage of our ranch style home into a master suite with WIC and bathroom, a mud room and dining room. We'll be building a new garage out in front of the current one.

We want to build the new space so the floor matches the height of the existing living space.

The drop is about 24 inches to the slab floor of the garage. The garage is build on top one a single course of 4x8 block. (yes, we have 2x4 walls we will fir out to 6 inches for insulation purposes).

What would be the best way to handle this new cold zone? how would you insulate? there will be water and gas pipes running between the joists along with hot water pipes for our baseboard radiant heat.

Two builders suggested two different methods.
1. To cover the slab floor and walls with vapor barrier and seal with spray-foam around the sill plates.
2. To cover walls and floor with a vapor barrier but then to insulate the I-joists with XPS underneath and fill with cellulose and then vapor barrier on top of that.

We don't want to get this wrong, please help.

Gary in WA

If you go this route, no vinyl flooring above; http://www.buildingscience.com/docum...n-crawlspaces/ but then you would want to vent the crawl (required by code, with slab v.b.)- and insulate the pipes. Though I wouldn't v.b. the wood walls. Foamboard or SPF the rim joist walls is good to air seal: http://www.buildingscience.com/docum...l_seal_rev.pdf

Sill-sealer under the plates/slab for thermal/capillary break; http://www.greenbuildingadvisor.com/...-building-code

Gary
P.S. Welcome to the forums!

__________________