Subloor insulation can be done using a variety of different materials as I’ve witnessed on blogs and youtube videos. What I chose to use is Lowe’s GreenGaurd foam board.

To apply the insulation I cut a compilation of 2 inch and 1 inch sheets to fit between my subfloor joists. The idea is to get as much insulation in the floor to close air gaps. Since the subfloor is the depth of roughly 3.5 inches I had to put several layers depending on what I had available.

subfloor insulation

When things didn’t fit as tight as possible as foam board material, I used “Gaps and Cracks” spray to fill those areas. You’ll find things don’t always align to the top surface of the joists either, so gaps and cracks can help with this and I also plan to seal my flashing underneath the trailer a bit tighter once the plywood sheathing is added after.

Once the gaps and cracks hardens, 15 minutes later, you can cut it with anything as it usually flows higher than your framing. I used a handsaw as I found the length of the saw being over the width of the framing space helped keep a level plane.

At the end of the day I started accessing some new 3/4 inch pressure treated plywood for the sheathing of the subfloor, which still needs to be cut and adhered. I’ll show that step completed in the next posting.