Insulating Crawlspaces & Elevated Subfloors

March 7th 2005
Insulating Crawlspaces & Elevated Subfloors

Dear Shell,

I live in a split level home. The mid level is on a crawl space (approx 3.5') with a concrete foundation. The floor is Pergo laminate and I find it very cold. I've gone into the crawl space and pushed pink insulation between the floor joists, but I still find the floor cold. Note, that there is a furnace outlet dispersing some heat into the crawl space. Have I done myself a disservice with the insulation? Would it be better to leave the insulation on the floor on the concrete foundation? Or do you have a better recommendation?


Dear Paul,

Insulating crawlspaces and elevated subfloors is best accomplished with the use of Reflective Foil Insulation.

Follow these instructions:

- Insulate the concrete walls with 1 1/2 inch poly urethane rigid insulation.

- Remove the glass fibre insulation.

- Apply Reflectix Foil Insulation between the joists 1 inch away from the underside of the plywood or shiplap floor.

- Replace the insulation batts up against the Reflectix.

- Insulate between the joists over top of the concrete wall and seal with 6 mil poly sealing with acoustical caulking.

It's Just That Easy,