Mmmmm Insulation and Subfloor Blog
Updated: Dec 24, 2020
Get ready for another skoolie blog. This one is about some truly scintillating subjects- Insulation and subfloor.
Although we searched around for a tall-ceilings school bus, we were still very conscious about interior height. Since we planned to live on our bus full time for an undetermined period of time and Spike is 6’4’’, we wanted to make sure he could stand in the bus without rubbing his forehead on the ceiling.
We started with a stripped out metal skeleton of a bus. We had previously taken out the perforated sheet metal ceiling panels, super-thin fiberglass bat insulation, and the rotten marine plywood subfloor.
We tried to grind away as much surface rust as we could from the floor then hit it with rust converter. I’ve seen alot of people really go at it with the rust but it honestly feels like the rust is the only thing holding the bus together so we didn't want to remove too much. We then filled all of the holes from the bench mounting hardware with caulk. Next we used construction adhesive to attach 2x4’s on their side to the floor.
We decided to go with spray foam for our insulation. We found a kit online with 600 sq ft at 1 inch thickness, since our bus body is only about 30’x7.5’, this would be plenty to cover at 1.5 inches (the depth of the existing metal ribs). I ordered it and it ended up taking wayyy too long to come in. UPS apparently forgot they could delivery to a commercial building ??? In any case just when i was about to charge back my cc and go get it at home depot, it finally arrived. The 600 sq ft is actually much more than I would have needed for just the ceiling and I wanted to insulate the floor as well. Originally I was going to use foam board insulation on the floor but I felt like a goober going out to buy more insulation when I was going to have excess spray foam.
I thought I was prepared for the foam, but i was not. I watched the recommend videos and everything but it was still too radical for me. Spray day was back in July during one of the 95 degree/99 % humidity days so I tried to get an early start. I donned the bunny suit and gloves and respirator and goggles at 6 am and assembled my spray foam canisters. I started spraying and the foam started expanding- everything was going according to plan. After a couple minutes I started to feel like i was getting the hang of it despite the large chunks of excess foam dropping on to me. I had no idea how much time had passed, I was in the foam zone. About half way through the bus i bend over and saw some liquid drip on to the floor. I thought maybe the foam gun wasn’t mixing the two canisters properly but in fact it was my sweat soaking through my clothes and the bunny suit. The foam radiates heat as it cures and hardens and although I knew in my head that it gets hot when it hardens, it just didn’t connect that doing it inside a metal box would make it into an oven. The sun had come up and was blasting the bus and the foam’s exothermic curing had raised the temperature in the bus to at least 130 degrees. But the directions clearly stated if you stopped spraying for more than 5 seconds, the foam hardens in the gun so i had to keep moving. before you tell me i’m an idiot, yes, the windows were open but it just didn’t matter with 600 sq ft of hot foam roasting my stupid flesh. at this point everything began to get hazy and slippery. I sprayed the rest of the ceiling and the floor around the 2x4’s. I tried my best to keep a uniform 1.5’’ thickness but it was tough as i was existing as a blistering Brussel sprout waiting in the oven to be eaten.
When I finally came to I was sitting on the tailgate of my truck in my skivvies with my sweat soaked clothing strew across the concrete with a bus full of foam- in other words, mission accomplished.
The next day i took a look in the bus to find that everything was more or less a uniform 1.5 inches. far from perfect but i figured the closed cell foam has a higher r value than the foam board and fiberglass so I latest wasn’t any worse off than if had used those.
Now to the subfloor. As the strange workings of the universe often do, I found the answer to my needs were right in front of me. The facility that I had been renovating the bus at shared a common utility to a roller derby league. The league had taken a large room and turned it in to their practice rink complete with plywood boards. Because of the pesky and lingering global pandemic, they could no longer fulling participate in their rolling derby and therefore had no more use for the well built boards. With a little effort and a whole lot of help from my flatbar friend, I had all the sheets of plywood I needed right there at the other end of the building. I quickly cut those down to 90 inches and screwed them into the glued down studs and out la vois la - my subfloor complete.
this will conclude this blog post. Please disregard what have just read.