Frame on, subfloor replacement over water tank?

[The BB]

Hi folks.

Im about to lay down new subfloor over the water tank and the last front part of this 1974 trade wind.
How to go about this. There is not a lot of room from the bottom side of the subfloor to the top part of the water tank. So I don't fell good about installing a piece of angle iron across to be able to land a sheet of subfloor there is split in to.
Can I split it in to 3 pieces 2 skinny pieces there is laying over the "wings" and one over the hole tank?
How have you guys come around the part. Any suggestions are welcome.

Have a good day?

Esben

[Dingo Girl]

It looks like the lower wall skins are still in place.
If that's the case how will you bolt shell to floor & outriggers?

[dbj216]

Hello from Colorado: Welcome to Air Forums and the vintage Airstream hobby. The Trade Wind 25' is my favorite model and a very popular size.

So we don't know how your Trade Wind ended up in this condition. As Dingo Girl said, usually the lower interior skins are removed when doing a subfloor replacement. Usually the belly pan is off also. And many times vintage Airstream enthusiasts remove all the bolts and rivets holding the body to the frame. The subfloor is sandwiched between the body and the frame.

Body on subfloor replacement can be done. I think Dingo Girl did it to her trailer. Some folks lift the body just high enough with it loosened from the frame, maybe 1/4 inch, to slide a new piece of plywood between the body and the frame from the outside in. The plywood subfloor goes from exterior skin to exterior skin on the other side. Then the body sits on it and is bolted down to the frame and the plywood. Piecing isn't as good, but can be done.

I might add there is plumbing and other items that ought to be addressed before the subfloor is replaced. For example, I don't see the fresh water fill line to the tank. Or the wiring for the fluid level for the tank. Maybe the tank drain valve is under there somewhere. And the inlet line for the water pump. All more easily installed before the subfloor goes down. The tank in your Trade Wind is just like the one in my 75 Overlander.

Maybe others more experienced in these things than I will offer some suggestions.

David

[66Overlander]

Putting floor seams over the main rails will weaken the structure, effectively causing the outriggers to hold up the full shell weight. The Airstream structure relies on the strength of a full width plywood floor. If is it put in in two pieces, a backer board several inches wide should be screwed and glued below the seam to restore the strength.

Since you have a tank between the rails that prevents a backer board in that location, you could consider the split outboard of one of the main rails, where a backer could be provided. One piece would be about 7' long/wide and the other about 1', give or take.