What's the best way to get to U channel when replacing a section?

[kramynot2000]

Well I've pulled all the old carpeting out of our '78 Sovereign and found a few sections of the floor I need to replace. One section is in the rear where I have about 1/4" of separation. My plan is to cut out the small floor sections and then slide in replacement pressure treated plywood. From reading past posts on this site, it seems that the plywood needs to be bolted to the frame and then the U channel screwed to the plywood floor and then the skin rivetted to the U channel, right?


So, to access the U channel I'm thinking I should I drill out the rivets in the interior skin and peel that back. Then I can screw the U channel to the plywood and then re-rivet the interior skin. Is this the best way to approach this? From what I can see in the little crack, the U channel seems to be in good condition, not rusty at all.

Also, I read an Airstream technical bulletin that discussed bolting the U channel through the plywood and onto the frame below. Seems I should do that as well and it would be easy to do if I have the interior skin pulled back.

Anyway this all doesn't really sound too difficult. Am I missing something?

Thanks,
Tony

[Chuck]

Originally Posted by kramynot2000

Anyway this all doesn't really sound too difficult. Am I missing something?

yeah. don't use pressure treated wood. its for outdoors only. It will off-gas toxic stuff that is used to preserve it. not a problem outside, but it is in a confined space.
most use marine-grade or ACX plywood of the proper thickness, and treat the edges w/ penetrating epoxy to prevent future rot.

[2333]

Chuck,
Thanks for answering a question I had posted, which didn't get noticed. It was about using ACX because I thought it didn't off-gas, but could leech when wet.
Other thought.... don't you have to have some sort of barrier between the aluminum and the ACX to prevent corrosion (epoxy, por-15, linoleum, etc)?
Thanks

[Chuck]

well...no wood reacts well to water. I don't think there is an issue w/ metal corrosion. that's just a problem w/ disimilar metals; don't think there is one with "metal & wood".
in any case, I'm no expert on any of this. there are alot of threads out there that talk about the various subfloor choices that people have made. seems that most people try to do something to prevent rot due to future leaks, whereas the factory assumed "no future leaks"...(ha!).

[malconium]

Actually a very good reason for not using treated plywood is because it is very corrosive relative to metal that it comes into contact with - especially aluminum. I replaced my entire subfloor with ptd plywood of the new variety which is not so toxic only to find out shortly after I was finished that it was even more corrosive than it used to be. I had to take it all out and do the job again. I used a product called Polyboard instead of plywood because I decided I wanted something that was completely waterproof and rot proof. Lot of people use plywood with good sucess - I just wanted something more permanent. For those interested you can read more about what I did at the following thread.

http://www.airforums.com/forums/f36/...ice-14620.html

On another note I think you will find that on your vintage Airstream that the u-channel has a c-channel on the bottom that the edges of the plywood slip in to. You have to remove the plywood and slide the new material into the c-channel. Let me know if you need more information about this. One thread to look at is:

http://www.airforums.com/forums/f36/...ary-11814.html

In my post #74 I give a list of the tools and techniques that I used.

Malcolm

[kramynot2000]

I thought I had the U channel with the C channel underneath but it doesn't look like it. It looks like I just have the U channel, however I'll find out this weekend.

My plan is to drill out the inner skin rivets and peel it back to I can get at the channel. Then I'll remove the floor section.

[malconium]

I can tell you that in my 1973 unit the u-channel around the curves at the ends of the trailer did not have the c-channel on the bottom of them.

Malcolm

[GetOutDoors]

There are many threads in the forums that you can benefit from with regard to this task . ..

Here is one: http://www.airforums.com/forums/f4/s...ent-17197.html

If you don't find what you need there, go to the forums tab and conduct a search on 'floor replacement' and you will find more reading material of how to's then you have time to read!

Calvin