Floor insulation complete

I did it; I put in isocyanaurate under my floor. The "joists" or crossmembers holding up the floor are 3" tall, so there's a 3" gap between the bottom of the floor and the frame rails. I inserted the insulation in those gaps, just like you'd do in a house, except I didn't use the pink stuff, I used these 2" sheets of insulation. The floor itself is 1.75" thick wood, so I used 3" wood bullets with a 1.75" fender washer to screw the insulation into the floor above.

Above the floor is a sheet of polyethelene, a sheet of some kind of sound-dampening insulation, then a sheet of spongey stuff to make the floor give, then finally my fake-hardwood pergo.

I've noticed already that the floor stays warmer, especially after driving (the air whizzing across the underside of the truck cooled the floor down a lot). This is good. We'll see what happens after a night of cold air. Temperature here lately has been very warm during the day, like 65 degrees, then down to a cold 45 degrees at night. It's an unusually dry winter so we're getting desert-like temperature fluctuations. The wind is from the east so we're not getting ocean humidity.

I notice it's also a bit quieter in here now too! That's a big win.

The whole project cost me like $80. It took me from 9am to 6pm. I was exhausted afterwards-- I am not used to working like this. But it felt good to use my body for a change, instead of spending 14 hours a day in front of a computer.

I hope this insulation will help in the summer too. I noticed that the van would get intolerably hot on some afternoons after the sun went low enough to heat up the ground underneath the van. I noticed that the floor would be warm. I think the insulation will help prevent that heat from radiating inside. If this summer will be like this winter, I'll have plenty of opportunity to find out.