Patching subfloor. Tell me why this won't work.

[Bobkatbry]

76 trade wind. After several rainstorms to find and eliminate leaks I started to take out this one bad spot of sub floor after I was satisfied there were no more leaks. I dug out all the old rot from the C channel. After a few measurements and cuts I came up with this piece of new subfloor. All the screws and bolts are still in the same place they were before. I cut these notches. I used exterior plywood with a few coats of outdoor oil based Spar Urethane from lowes. I plan on inserting this piece of new floor. It's a tight fit. Give me a quick answer as to why this could or could not work.

[joqin]

I had the same problem in the rear of my 65. I put it together ,then ran a bead of expanding foam along the edge. Hasn't moved or leaked in 15 yrs, and it get covered up by the couch,etc. joe in MN

[Bill M.]

That will work fine for patching the floor. I have done it that way and was pleased with the results.

Note: There is a down side to this type of patching. That is, the trailer is held to the frame via the bolts through the C channel that you notched around. If enough of those bolts are rusty enough to fail the trailer shell could separate from the frame. Not really a floor issue but something to think about depending up how extensive the area patched is and how rusty the bolts are. The only way to change those bolts is to take off the belly pan and the lower inner skin (or cut holes in it). The bolts and the floor are separate issues. At the extreme edge of the panels it matters not a whit whether the bolts are drilled through the plywood or notched around. All the wood does is hold the C-channel from collapsing so notch it in good.

[brokeboater]

Originally Posted by Bill M.

. All the wood does is hold the C-channel from collapsing so notch it in good.

I had a similar situation on my rig and did a similar repair. Where the plywood was rotted at the bolts the aluminum channel deflected down, and up, due I suppose to no adequate support for the aluminum channel. The larger the notches the less support given to the aluminum channel. I would think over time that would cause a loose connection between the shell and trailer. I chose to only notch out for the bolts at the steel trailer C channel connection and re-drill and replace the aft eight 1/4 20 bolts connecting the shell to the trailer. I also sealed the entire piece of ply with epoxy and a little extra attention to the areas surrounding the two bolts I notched around.

So far it's been strong like ox, but I haven't gone anywhere yet. A Florida to California fast shakedown run in on the docket in less that a week though.

[prairieschooner]

Looks like there are two areas of repairs. The problem that I foresee is the glue area of the joints. Typically a scarf would increase the glue area and then using something like epoxy as the adhesive. Here is a picture showing my repair, I laminated the repair with numerous layers using a 12:1 scarf;

[rdb504]

Looks like the same area I had a problem with when I first purchased my 73 Ambassador, did the same repair. While you have it out its a good idea to get a water hose and spray, starting at the bottom to find the problem area. We found ours on the first try. Seems it was coming in under the rub rail, right at the floor level. We used Parbond to seal, and haven't had any other problems.

[delongj]

Looks good to me! As others have said, I also patched my floor in this manner. I also ran several self tapping screws to the metal frame under the piece of plywood. I had to tapper the fit into the C-channel. The rain was coming into the trailer from the antenna port in the ceiling and running down the wall. I took off the antenna and rivited an aluminum sheet of about six inches by six inches to cover the hole. Then I painted the whole roof with a white paint used to drop the trailer temp about six to ten degrees. What I liked was that the paint definitely sealed any possible water leaks! Good luck with the project and don't forget - momma likes thick padded carpets if you are going that route! jd

[Devananda-E9]

That's what I did and it works fine. Looks likr you did a really neat job of it.

[BigButtUgly]

Is there the option to actually cuting off all bolts, slide the new piece under , screw it to the trailer frame? Then lay "L" angle metal up tight to the wall, screw it to the plywood and pop rivet the vertical through the aluminum and into the upright portion of the "C" channel. Would this not do the same thing as what the bolts do? Shell now fastened down.

[HiHoAgRV]

Somebody did the same repair on my '63.

I could grab the forward edge of the door frame, pull and the entire wall would slide in and out.

The wall's gotta be attached to the floor and the floor's gotta be attached to the frame.

[BigButtUgly]

HiHoAgRV: Re-read BigButtUgly post. When the upright portion of the "L" angle piece is screwed or pop riveted thru the inner wall and into the vertical piece of the "C" channel, the inner skin and "C" channel sitting on the new plywood can not move back and forth. The outer wall can not be lifted off the new plywood by virtue of "L" angle holding it down. My 58 Caravanner entire front end was repaired in this way. Most difficult part was hack sawing the 10 foot "L" base to make the radius bends on 2 ends The "L" angle was long enough to stay inside of the 2 side walls . As the new plywood is pushed forward it raises the cab. Then the plywood is screwed to the frame.

[matthewsx]

Older thread but here's what I do.

Remove rotted floor section
Cut old bolts with angle grinder and cutting wheel
Drive new subfloor section into "c" channel with mallet
Drive new "trailer deck screws" through the whole sandwich into steel frame.

This can be done from inside without removing banana wraps.

John

[matthewsx]

Also, I use a backing board screwed to the underside to support areas that aren't resting on the frame.