Non-wood subfloor for trailer

[theoldwizard1]

I am contemplating build an enclosed trailer and trying to cost out materials. The goal is to keep the price "reasonable" and the weight low.

Most enclosed trailer use 3/4" T&G plywood for flooring, just like houses. The problem is, they will be subject to moisture from below and possibly above if the roof leaks. Moisture causes wood to rot. Replacing a floor in an enclosed trailer likely means disassembling any interior and the walls.

Something like the 5/4 PT deck boards is an idea, but 1) they are very heavy (more than 3/4" plywood) and sealing inbetween to prevent road splash is going to be almost impossible.

Aluminum planking is too expensive.

I am considering making a joist system out of 2" 0.125 wall aluminum square tube, adding bracing between the joists and 2" rigid foam between these members. Finally cover the whole thing with fiberglass. Lots of work, not cheap (3-5 layers of glass ?) and of course you really need to do both sides ! How about gluing down some kind of rolled aluminum ?

Azdel (a synthetic panel used in RV sidewalls) is interesting, but it is typically only 1/8" thick and not available to "consumers".

Any other ideas ?

 

[Hilltopmasonry]

Fiberglass the underside of the deck/plywood before you screw it down


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[rsanter]

How about thin galvanized sheeting put down on the trailer framing and then seam sealed.
Then add the wood flooring over that. Then you can paint it with a flooring paint

 

[theoldwizard1]

bump

 

[CJDave]

What about composite decking material? CJDave.

 

[driftpin]

I've had several light trailers over the years, and the floors that worked well for me were 4 x 8 pieces of aluminum diamond plate. I went to the scrap yards until I found them, & made sure the cross-pieces were spaced to support whatever the loads were. Usually that would be 24" o.c. I wasn't carrying CMU's or pallets of sod.

 

[like2wheel]

Why not pressure treated plywood?

 

[Matt M PA]

My 1995 Hallmark is plywood. It was heavily undercoated when new.

 

[NKlamerus]

Roll on bed-liner over wood does wonders. Stay cheap and plan to rebuild it once a decade-along with the trailer lights.

 

[mike93lx]

You are way overthinking this. Just undercoat the plywood or use PT. If it rots, cut out the section and repair it.

Thinking about laying 5 coats of fiberglass on a trailer floor is insane, IMO.

 

[moab11]

PT plywood, then use a DIY bedliner paint on the inside and the floor should last a long time.

 

[theoldwizard1]

What about composite decking material? CJDave.

Heavy and $$$

 

[2gslse]

I would look into advantech flooring it is water resistant and used as subflooring in homes. It might be a good floor in a trailer

 

[johnnyradiant]

pt ply.

I live in the Pac NorthWet. We get plenty of life out of pressure treated ply.
If your building it couldn't you design the thing build the walls first then install the decking so changin it down the road (pun intended) isn't such a big deal.