Floor Repair and Wood Choice

[JimmyJames]

I have my 74 Tradewind interior stripped. I have removed the belly pan enough to see everything and the metal is solid, a little ferric oxide fuzz here and there but good.

I took an awl around the entire perimeter of the floor and since it's near Halloween, stabbed the floor in a way that might raise the inquisitive eyebrow of Tim Burton or perhaps even Alfred Hitcock if he were still inventing horror.

The only place the floor was bad was in the rear along the back and a quarter sized spot next to the battery box (the exterior door rubber is gone in that section and the door was bent out a bit catching the rain.)

From what I have read and from my experience with the pieces I took out, the rot that appears on the top seems to be slightly smaller than the bottom was. The difference might be attributed to the weight of the water top to bottom from the wicking and lateral spread or the wick related to surface tension pull from top to bottom and side to side - but the difference is only 2 inches or so from the way the top looked from the way the bottom looked, not that pronounced.

This coach has the typical dissimilar metal, aluminum hinge and exterior siding to ferrous right angle support piece issue. The storage compartment lid wiggled and wobbled, that was the first clue there was an issue in that area. It had corroded and allowed the rain water to run in, supporting small communities of aquatic animals, I think I even scrapped away a few crawdads...

Now that I have clean and surprisingly solid aluminum and iron "U" channel exposed in this section and the rotted sections of metal and floor removed (floor pieces are two "J" shaped pieced split in the middle and spanning the width of the back which were full of rot. They are 6 inches wide}

My question to the "Guru"vious Nebulousitty, our community of generous experts is this - (many bows of endearment and respect )....

These two sections will already be supported at the frame on either side (I cut along the frame well beyond the rot) and along the back on the U channel where they will snug up under the "U" channel and be bolted there. These two pieces will be tied together from below with a strip patch and epoxied to the remaining solid sections of 3/4 ply. I will also reattach a new right angle support piece but use STAINLESS THIS TIME !

I know long introduction, short question - Can I use 3/4 inch Western Red Cedar (I have a nice piece of strongly aromatic rich red, vertical grain heart wood) or Rift White Oak , the mariners choice (vertical grain) ?

Any assistance will be appreciated...Thanks

[uwe]

Originally Posted by JimmyJames

Can I use 3/4 inch Western Red Cedar (I have a nice piece of strongly aromatic rich red, vertical grain heart wood) or Rift White Oak , the mariners choice (vertical grain) ?

Any assistance will be appreciated...Thanks

Are you talking plywood, or planks?
My first choice would be exterior grade plywood, the best you can afford. Many swear by the Marine grade plywood.

[Bob Thompson]

Western red cedar and white oak are both very rot resistant woods. There was a time in my life when I made fence posts from western red cedar. Conastoga wagon wheels used to be made of white oak. Cedar is light weight and brittle. White Oak is heavy and tough. If it were me, I'd use douglas fir marine grade plywood in a thickness matching the original. Douglas Fir marine grade plywood should be somewhat common most places. The red heartwood of douglas fir is also very rot resistant. You may want to treat the wood with Olympic Stain Wood Preservative for an extra layer of protection prior to installing any flooring.

[JimmyJames]

Bob and Uwe, Thanks for the replies.

Of course the obvious choice is marine ply at three quarter. It costs 40 some dollars for a full sheet (the only way its sold). I wondered if there was any problem with the other two choices that I was not aware of.

The marine ply would have one, six inch strip taken from the 4 foot side and the rest, a 3.5 x 8 foot piece of ply would lean against my shop taking up room. I have the other two species laying around.

I liked the cedar for the fact that it is toxic and would likely not rot even if it remained wet. The oak is damn hard and also good for rot resistance but not nearly as good as cedar. The only thing is I have read a lot of posts on the forum and no one has mentioned making small, non' structural splices with anything but marine ply.

I thought that maybe there was an obvious reason why that I was somehow not understanding.

I'm feeling lucky, so I think I will go with the Oak in this case and same myself a few bucks. I might regret it but hey, mild trauma builds charactor.

Thanks guys !

[fastrob]

The beauty of this forum is the diversity.
I think of an Airstream as an airplane on wheels with a backbone sheet of plywood for shock absorbance and strength. Pound for pound there is nothing better than plywood where appropriate.
With small areas of weakness in the floor you are ok. Some have reported major decay and still functioned.
Mine is sitting until I can do it right.

Please share with us how it works out and if you can pictures are sweet.

R

[CanoeStream]

Douglas fir plywoods with exterior glues are common. The difference in marine grade is that all gaps and missing knots are plugged, giving no internal airspaces to hold humidity. I did not have ready access to a good marine ply source. I did find an underlayment grade, I think the yard called it BXB, that by definition has less gaps and internal spaces -- though I did find some. Odd thing is that it comes in strange thicknesses. You'll probably be removing back to some sound floor. I found the original ply to be 1/2", so the 19/32" BXB was as close as I could get -- not the best match depending on where and how you'll be doing the finished floor.

Digging deep under cabinets to winterize my Safari last weekend I found about a 4" x 12" opening in the floor for the plumbing to access the fresh water tank. The quality of Airstream's cut in that ply floor was superb and showed the most excellent, solid plywood I think I've ever seen. They use some good stuff!

[JimmyJames]

Rob and Bob,

Thanks guys. As I typically do, I decided, just prior to pulling out the oak board, to make a run to the lumber store. I realized that ply really is the only choice simply because of the dynamic strength issue. I assume that there would be stresses on the rear-end that I could not interpret. As hard and weather resistant as Rift Oak is, it still has a grain and could split. Ply would not.

I paused this morning, remembering spending 3 long days sanding all the bathroom fixtures to one color, starting with 200 grit ending with 1000, then going through a polishing step. All that work, tear-out and soon the re-assembly of the bath would be undermined by a cracked board on some boon-docking trip down an uneven road, sure as shootin.

One benefit of getting older is the gift of patience. What matters most is to do it right.

I finished it today, all new, with a .125 stainless hinge plate this time for the rear storage door. Much more rigid and solid than the T2 .040 soft aluminum strip it did have which was powder everywhere it met the U channel.

The patches looked great and fit nicely, I used foaming polyurethane glue which expanded nicely into the gaps well above floor level, which I was able to sand off smooth without having to come back and fill those gaps between the patch and the main floor. I also painted the marine ply on the edges and where it goes under the channel on both sides with a black oil based enamel.

I replaced the old rotten right angle support piece in the back with marine T6 1/8 inch aluminum instead of the mild steel that it did have.

Everything (all the new parts got a mild muriatic acid wash (8:1) and POR-15 prior to reassembly. All riveted and sealed. All seams at the back have a thin bead of Vulcum and the interior wall got the same rigid white rubber based sealant, similar to what the factory used.

Turned out great. I am so grateful to all the threads I have gleaned information from and for the kind replies from everyone.

I have a series of pics I have been taking but have yet to organize and load. Remembering to take them in the heat of battle though is the toughie.

Thanks guys, we never have enough time (or money) to do it right the first time, right ? but always have both the second time around. If I learn anything during this restoration, it will be patience. As one member advised me early, it is a series of individual, small, but achievable projects. One at a time.

[markparker22]

I believe the exterior grade of plywood like CDX is good enough for floors since the marine grade is "exterior" rated, without voids, for a ship's hull integrity. The CDX will have some spot voids but I would make the decision based on price and your budget.

[JimmyJames]

Thanks Mark.

I got marine and it's in. I remember an audio report on an amplifier I wanted years ago. It said that the total harmonic distortion on the unit was .005 and I wanted to know what that meant.

I looked it up and found that only dogs and bats could hear and distinquish that level of variance.

I wonder if this issue of Marine vs. CDX is similar, especially if CDX is painted with a non metalic oxide primer. We might be nibbling around the edges. I think you are right, but non-the-less I popped for the marine but they sold smaller "handy panel" which was a partial sheet, it met my needs and saved falldown waste and money.

Thanks again...

[JimmyJames]

Thanks Mark.

I got marine and it's in. I remember an audio report on an amplifier I wanted years ago. It said that the total harmonic distortion on the unit was .005 and I wanted to know what that meant.

I looked it up and found that only dogs and bats could hear and distinquish that level of variance.

I wonder if this issue of Marine vs. CDX is similar, especially if CDX is painted with a non metalic oxide primer. We might be nibbling around the edges. I think you are right, but non-the-less I popped for the marine but they sold smaller "handy panel" which was a partial sheet, it met my needs and saved falldown waste and money.

Thanks again...