Insulating the floor is one of those tasks for which there are as many approaches as there are vans. While we're concerned about heat retention, we're also frugal as to interior headroom. I'm 6' tall, and Brian is 6'4". We can't afford to stack layers of rigid insulation under the floor!
Insul-Bright offers an affordable and (we hope) effective solution. Yes, its primary advertised use is oven mitts. Also, you find it in the craft aisle. The blue-checkerboard packaging let's you know you've found the right stuff. We bought two bolts. Now grab your scissors!
Most of the floor will have two layers of insulation beneath it. We'll attach one layer to the underside of the floor between the risers. The other layer will be spread across the van floor just before we attach the subfloor to the van itself. But first, cutting and attaching the Insul-Bright.
QUICK FACTS Time Spent: 6 hrs Dollars Spent: $110 Products Used: * Insul-Bright insulation * 3M 90 Low VOC (adhesive) Tools Required: nothing special Frustration Factor: mild
Precision isn't required here, or at least we didn't employ it! I measured the interior space between risers, cut to the proper length, folded to the proper width, and then cut along the fold. This is a somewhat messy job, as some fibers will come loose during cutting. It will also dull your scissors. That said, it's pretty easy work.
Meanwhile, Brian sprayed adhesive onto the underside of the subfloor. After extensive research into the toxicity of such materials, he chose 3M 90 Low VOC spray adhesive. We had to order it online, as we couldn't find the low VOC version at local stores. We sprayed both the subfloor and the strips of insulation, as directed.
With adhesive on both surfaces, the insulation sticks easily to the plywood. We smoothed it with our hands a bit, and we trimmed some of the overhanging edges. Otherwise, that's about it!
The second layer will go directly on the floor of the van itself. We laid out the insulation just to make sure we had enough left after cutting the strips for the subfloor. Either our powers of estimation or luck was on our side!