Would you use spray foam on the floor?

I am new to using spray foam - just started the walls yesterday, but I am wondering why people don't use it on the floor? It seems that be the perfect solution to filling the uneven valleys in the flooring. I assume if I have an issue with curing too quickly I could even cross cut the sub flooring so it can be laid down in smaller sections. I don't think seems will matter because it is just sub flooring.

Don't hesitate to tell me where I am going wrong!

FYI:
I am taller so I want to maintain as much height as possible. I have sound insulation installed and now I plan to reinstall the already cut flooring from my 2002 Sprinter with a small layer of insulation under it. On top of the original floor I will be adding coin rubber flooring.

Spray and rigid foams can develop squeaks over time as the vehicle flexes and the foam breaks down or comes loose from the metal. We recommend minicell foam for under the floor. It's a resilient, compliant foam that is moisture resistant, light weight, and easy to cut into strips.

hein said:

Spray and rigid foams can develop squeaks over time as the vehicle flexes and the foam breaks down or comes loose from the metal.

Click to expand...

Not a squeak to be heard after 10 years and 200+k miles of hard use with my spray foamed van.

Not a single indication of any degradation and absolutely no pulling loose anywhere. I pulled a door panel this Spring to add some wiring.

Hein, I know you sell a different insulation with other good properties. Can you site actual instances of correctly applied spray foam failures? Or is this just the party line from the Thinsulate folks?

Not an attack, just curious why your info differs from my real experience.

Dan

Spray foam on the floor would be time consuming to level. Easier to just fill the low portion with 1/2" closed cell foam and put a layer of polyiso on top of that with plywood on top of the polyiso. Nice and level when you are done.

Did it a little different in the Transit:

http://www.ortontransit.info/testfloor.php

The 80/20 framework on top of the floor makes it easy to attach cabinets.

Curious why people haven't used spray foam in the cavities under the van to insulate the floor? I've seen RVs and trailers done that way