Installing flooring in a van is the first step (wish I'd known when I started :) to conversion to an RV. I chose laminate click flooring because it's easy to clean, durable, and I love a bright wood look.
I built this at TechShop
in San Francisco. Living in the city I don't have room for tools and the wood shop there made cutting the flooring to size a piece of cake.
Step 1: The Plan
* Click flooring (Laminate/compressed wood)
* Underlayment (1/4" Cork)
* Moisture Barrier (Plastic)
* Flattener (Reflectix to fill ridges in floor)
* Bare, prepared van metal
Step 2: Prepare Metal
Prepare the van interior by cleaning, sanding out any rust, and repaiting. You aren't going to see the actual van floor again (hopefully ever), so don't leave any rust around to melt your floor out from under you. I also chose to paint with a layer of sound dampening paint like Lizardskin but this is optional.
Step 3: Fill Gaps to Level the Floor
The floor of most vans has 1/2-1/4" ridges that help make the floor more stable. I wanted to bring this up to a level height so that an installed floor would me more stable. Also, the more insulation the better :)
Reflectix is a good choice because it's made of plastic so it can't hold moisture or rot. It will provide a small amount of radiant heat insulation (good if you park over a hot parking lot).
To fill the gaps, I simply cut it into strips and taped it down. Having a buddy to help makes it go really fast.
Step 4: Add a Moisture Barrier
Because you're gonna put a floor down, and because all humans exude humidity, and especially because I spill things and make a mess, you need a moisture barrier. This keeps moisture off your van's metal floor.
Buy a cheap roll of the stuff at home depot. It's just heavy duty plastic. You attach it with silicone and keep a water tight seal away from your van's metal floor.
Pretty easy stuff there.