Foam Core Floor Repair. Epoxy?

valhalla360 wrote:


The foam that got compressed is already compressed, so it's less likely to compress a lot more.

While it's possible areas around the original compression will fail, the limited space in RVs tends to create very distinct walking paths. If an area hasn't degraded yet, it's unlikely to do so in the future as it rarely get's walked on.

The skins in the sandwich construction rarely fail in compression or tension, so the holes won't be a big concern. If you go in from the top, they will be filled flush anyway and work in compression. Epoxy does fine in compression.

Tearing out the floor entirely, is a drastically larger project and generally not cost effective.

Slapping a 3/8" layer of plywood on top will leave a spongy spot. 1/2" would be the bare minimum and you may still notice it flex a little. 3/4 much better but now you are significantly eating into the CCC of the RV particularly if it wasn't large to begin with when there is a cheaper viable solution. Also, any of these can be much more challenging if you have a slide that needs clearance over the flooring.

The foam isn't the real problem, it is the fact that top of the subfloor is too thin. Most likely less than 1/4" thick! That leads to the wood fibers and glue in the subfloor to break. Once that happens you are now depending on the foam core and the underside of the floor structure for strength.

You don't just "slap" another floor on top, you GLUE the new subfloor to the existing floor.. This is called laminating and even 1/4" or even 3/8" material glued/laminated on top of the existing floor will increase overall strength well enough to reduce any flexing.

Older RVs like my 1980s trailer used 5/8" plywood as the top of the floor, 2" of polystyrene expanded foam insulation (looks like beads) and 1/4" plywood on the underside..

Newer RVs use 1/4" on the top and 1/8" inch on the underside.. A failure waiting to happen.