Poly as a suitable floor replacement

[nomadicitch]

I've read several posts on the site about using metals and other non plywood materials to replace rotten floors. However I haven't yet stumbled upon one that mentions using a poly or other high density impact resistant plastic. Does anyone have any experience with these materials in such an application? Also welcomed are hypothetical pros/cons.

[Night Sailor]

Sound fragile to me. A fiberglass floor, either solid or cored would be the best choice IMHO. That would allow you to bond it water tight to the shell. A cored floor would be light and strong but require the core to be removed and sealed on the edges and anywhere there is a hole.

[Terry G]

I think the OP is probably talking about HDPE (High Density Polyethylene) or maybe some other extruded plastic like nylon. It's an interesting concept since that stuff is extremely tough and resistant to almost everything. In order to walk on it without sag, you'd have to go pretty thick, and that could be rather heavy and expensive. A 4 foot by 8 foot sheet, 1/2 inch thick from Interstate Plastics would run about $192, not including freight.

They also handle a glass epoxy sheet (called G-10) that might be a better choice since you could go with something much thinner and lighter. That's even more expensive, running about $300 for a 1/8" sheet 4 feet by 8 feet.

[tractors1]

I've worked with poly = it IS pretty heavy stuff and doesn't hold screws very well. Joining it also takes a plastic welder gun. G10 would probably need to be 1/4 inch thick as it flexes fairly easily.

Charlie Y

[Dan Meyer]

It seems to me it would be slippery all of the time and you would not have much traction for your feet.

Plus, doesn't it change quite a bit dimentionally with temperature changes? It might be hard to keep flat.

-- Dan Meyer

[Night Sailor]

The deck on my big boat was two layers of fiberglass with an inch core of end grain balsa wood. It was strong until water got in. The edges were not sealed. I recored the damaged areas last year and sealed the edges. I recommend it highly if it is peppery installed. No flex, very light, and strong.

I don't know anything about these plastics. I suppose you could bond the to fiberglass shells if the surface was roughed up. It seems doubtful that rattling around on the road would hold up.

[nomadicitch]

I appreciate all of your responses. I hadn't considered its ability or inability as it would seem to prevent screws from backing out. If it were merely a matter of the price variance, I might give it a shot for the peace of mind that I would never have to deal with the rot again. Guess I'll stick with the glassed marine grade plywood option.

[David Morgan]

There is a product called resin deck that is high density plywood, made with some very industrial resin. My company builds mezzanines with it that fork lifts drive on. 3/4", its also very commonly used to make highway signs as its very water hardy. The biggest 2 problems I know of in using a poly"plastic sheet good" for floors is one its usually too flexible, and almost nothing will stick to it.

The resin deck can be ordered with a high durability poly coating on one side with a smooth to aggressive texture.

Walk tread grey



Grey and tan bull hide texture.


This brand has a polyethylene too service. One huge advantage here is that fiberglass will stick to one side at least. You can also grind back the plastic if you needed to glass to the surface too.

[Andrew Gibbens]

Plastics like polyethylene (HDPE or not) have the problem that it's virtually impossible to get any sort of fiberglass to stick to them - it's hard even to find any adhesives that stick to them. So bonding the floor into the trailer body isn't going to work well.

There are boat core materials that could be used but they tend to be pretty expensive and would involve more production work (and hence even more cost).

(Oops, pretty much repeated David's points!)

[David Morgan]

I don't even think there is an epoxy that will truly bond to HDPE or UHMW-PE.

If you rough it up enough you can achieve a "mechanical bond" but it won't be reliable.

I have fiberglassed to PVC products but its still never a reliable bond.

From the marine products side there are some high density foam sheet goods and other "core" products that are strong, lightweight and water proof.

True Marine plywood is over $100.00 a sheet if you can even find it. Pressure treated plywood I have never found a sheet that wasn't warped to high heaven. And polyester resin doesn't much like sticking to that either from my limited experience with it.

Whatever you do stay away from Balsa!
Yes it's in boats, but its there because it was cheap and light and there were few alternatives. Not because it's a reliable sound solution

Asphalt emulsion on a good quality plywood, in a travel trailer should have no problem lasting 50+ years. As Long as its not subjected to long term water.

[rleete]

I refurbished my Trillium last spring. Gutted it, and installed new floors, as old ones were rotten. I used plain old plywood. The scraps have been sitting in my driveway exposed to the weather for the entire year, and have yet to warp or become more than slightly waterlogged. No delamination. If it can stand up to that, then being enclosed in a trailer (with no more leaks!) and covered with vinyl flooring, it should last for at least a decade, probably much more.

[MCDenny]

I've had a scrap of Hydrotech marine plywood (Meranti) laying on the ground next to my shop door to test the ply-Garapa veneer-epoxy-TDS caulked grooves I use as the sole (floor to you land lubbers) in my boats.

It's all grey but mechanically sound after seven years. The plywood is bare, no epoxy except to glue down the Garapa.

BTW, Garapa is a Brazilian hardwood very similar to Teak but easier to bond and much less expensive. That's what's on the seats and sole of this boat.


This would make a nice trailer floor too. The Garapa is just oiled so maintenance is almost nothing.