How to fasten walls to floor

[McFish1951]

How do you fasten the foam walls to the floor? Do I need a 2x4 laid down on the floor either inside or outside the wall to get a vertical plane to glue something to? A second question is this; my frame has a 2x8 flooring already installed as a floor. Do I need to paint it? Can I simply glue an XPS sheets on top of the floor?

 

[Pmullen503]

The main thing to worry about is keeping it straight while the glue dries.

I've done it a couple ways. First was to rout a channel in the edge of the sheet of XPS with a matching wood strip glued and screwed to the floor (1/2" x 1/2").

The second way was to first cover some 4"-6" wide scraps of plywood with packing tape. Screw those to the sides of the floor so they stick up a few inches. This is the outside of the foam walls. Then I screwed a 2x4 (also covered with packing tape) down to the floor 2" away from the plywood side pieces to form a channel for the foam walls.

Now glue down the walls. The tape on the wood parts keeps any glue squeeze out from sticking. You'll still have to use rope or straps to hold the walls in place and keep them straight but the bottom edge will be straight.

 

[tomhawk]

Do I need to paint it?

A lot of people here would say yes. At my job, I work in a basement of an old building. We get floods more often than I care to think. Water tends to flow down. Your floor is no different. Since water + wood == rot, Paint it and then think about painting again.

Also many people here think gluing canvas to the foam before assembling is a good idea. Not sure what the consensus is for fiberglass?

Here is the way I attached the foam wall to the floor on my build. Notably, I glued a strip of fabric to the bottom of the floor (see panel . Then when I glued the bottom of the foam to the floor I could wrap it up onto the bottom of the foam wall. I then glued the loose flap of canvas on the bottom of the wall over that. The advantage to me was that I did not have bend over to glue that flap on the underside of the floor. I could then glue a hem on the free canvas edge that constituted a "drip edge" (panel D) to help direct water away from the wood floor.

.
The wood strip on the inner side on the floor provides additional anchoring of the wall when wrapped with glued canvas.

The strength probably all comes from the canvas wrapping. I don't really think the glue between the foam edge and the floor contributes much.

This floor is securely attached. I have driven many hours at 70+ mph with no problems.
See: viewtopic.php?f=55&t=75248

Tom

 

[IrrationalExhuberous]

The wood strip on the inner side on the floor provides additional anchorin

Tom

How did you cut the foam neatly to fit?

 

[Tony Latham]

The wood strip on the inner side on the floor provides additional anchorin

Tom

How did you cut the foam neatly to fit?

Dunno how Tom did it, but I would use a router with a guide board attached to the foam. Six-bits says Tom used one too.

Tony

 

[tomhawk]

I used a wire hot cut tool similar to this one.

George goes into detail how to make these items. https://www.tnttt.com/viewtopic.php?f=55&t=55323
The power source is an old style 12V battery charger. The desired resistance is provided by making the wire long enough (3 feet). The extra wire was coiled up. You need to wear PPE to avoid getting burned.