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srgntpepper · 08-07-2003, 06:16 PM

Well I nearly have all of the interior gutted out and am getting ready to replace the front and rear floors using the "Clamshell" method. I just have a few questions......has anyone considered sealing the bottom and end cuts of the flooring with three or fours coats of polyurethane before installing to prevent future rotting problems???? Would really like to use CPES but can't get it before the weekend. Also Does anyone know how much more work is there in removing the entire body shell assuming interior skin is removed ( but not belly pan) I may just go all the way if not too much more is involved. Thanks for any info

74Argosy24MH · 08-07-2003, 07:20 PM

When I replaced the floor in my mh I painted the edges and cutouts with exterior paint. I figured it has to help.

You are not all that far from having the body off. There are bolts through the lower channel that have to come out and the banana wrap has to come off. If you have pulled the whole interior and skin, a little more work will give you a brand new floor and a chance to get a real good look at the frame. I had several large holes and the whole floor had a lot of flex, so it was a no brainer for me.

John

srgntpepper · 08-08-2003, 03:17 AM

what is The Banana Wrap?

74Argosy24MH · 08-08-2003, 04:37 AM

The curved panels around the bottom outside. If you have to replace the floor on both ends you probably already have most of it off.

John

Silvertwinky · 08-08-2003, 05:00 AM

Quote:

has anyone considered sealing the bottom and end cuts of the flooring with three or fours coats of polyurethane before installing to prevent future rotting problems????

Polyurethane may me good; I think it would certainly help. I replaced the front part of a floor in one of the campers I had and I used marine plywood. A bit more expensive but felt if it got wet it would hold up for a while.

Robert · 08-18-2003, 05:04 PM

I have been following the problem of rotted wood subflooring since I encountered it in my 1973 Sovereign. Quite frankly it has turned me off to the Airstream. The wood floor is bad design that continues to dog owners of the older models. It should have been eliminated long ago. The rest of the trailer is anodized corrosion resistant aluminmum and steel and we have this unprotected wood deck that ties together the entire trailer! And there are only two types of airstreams - them that leak, and them that will. So eventually all airstreams will meet an early death due to this problem.

As for repair. IF I ever decide to repair the entire floor I would take the time and effort to use marine ply and I would completely coat the ply with epoxy resin (top/bottom/edges). This will seal the wood, making it completely waterproof, basically turning it to reinforced plastic. Any thru-holes should be similarly treated. Cost of epoxy would add an estimated $300 to the fix, but in my opinion would be well worth the trouble.

I am planning on selling my AS, so this will most likely be someone else's project, but it is really the only good long term fix. I'm surprised that some enterprising person hasn't found a way to strap the fuselage to the chassis- bypassing the wood floor structure; and take the opportunity to create access hatches within the floor to all the mechanicals like tankage, plumbing, wiring. That would be a great upgrade.
Robert

gerbermania · 08-18-2003, 09:35 PM

There is no reason to use wood as a subfloor in a travel trailer, except for cost.

Plastic sheet subfloors have been used for years in boats.

There are many sources, such as www.codemo.com and www.kingplastic.com. The sheets are typically twice the price as a marine-grade plywood sheet, but they are far less of a maintenance headache, since they don't have nasty formadehyde or subsequently-applied waterproofing, offgassing into the interior.

These plastic sheets come in various thicknesses for subfloors, such as 5/8" or 3/4", in 4'x8' sheets. They absorb little to no moisture, so they won't rot like plywood.

AIRSTREAM's need to breathe a bit, but that shouldn't have to be done through a rotting wood floor.

christopher

j54mark · 08-19-2003, 05:59 AM

I am no materials expert, and I know almost nothing of boats, but I would personally be very leary of a plastic subfloor in a travel trailer. Marine plywood sounds good, though.

I have also often wondered why it would not be feasible to design the shell to be tied together at the floor with a series of aluminum stringers. These could then be fitted with plywood inserts that would drop in between the stringers. Any rot problems down the road (pun unintentional) could be dealt with on a piece by piece basis, without reconstructing the entire shell.

Mark

gerbermania · 08-19-2003, 07:50 AM

you probably know this, but for those who don't, marine plywood is not specially-treated wood. it does NOT contain any type of wood preservative or anything, the "marine" designation only speaks to the glue used, so the plys stick together while moisture is present.

as far as the plastic subfloor goes, it is probably a similar argument for metal studs in building construction. if we were to write building codes all anew, it is unlikely we would allow wood to be used structurally for framing buildings. It has too much pest and rot susceptibility when compared to alternatives such as metals, plastics, and composites.

at this point though, labor and material costs are really low with wood, due to the existing infrastructure and training level of general laborers. thus, so many mold and termite problems.

christopher

59toaster · 08-19-2003, 08:26 AM

Quote:

Originally posted by gerbermania
There is no reason to use wood as a subfloor in a travel trailer, except for cost.

Plastic sheet subfloors have been used for years in boats.

There are many sources, such as www.codemo.com and www.kingplastic.com. The sheets are typically twice the price as a marine-grade plywood sheet, but they are far less of a maintenance headache, since they don't have nasty formadehyde or subsequently-applied waterproofing, offgassing into the interior.

These plastic sheets come in various thicknesses for subfloors, such as 5/8" or 3/4", in 4'x8' sheets. They absorb little to no moisture, so they won't rot like plywood.

AIRSTREAM's need to breathe a bit, but that shouldn't have to be done through a rotting wood floor.

christopher

Ok let me ask this. One issue with a trailer is it flexes. Wood has give and will return to to it's previous shape to an extent. Will these plastics do the same? How is the weight to weight compairson? How is it structurally. I know it's going to be more rigid but at the point of flex is it going to break, bend or act just like wood?

I like the idea of no way the watter can cause a structural failure but I also have concersn with outgasssing and other issues.

At this point I'm looking at going with a Epoxy Resin or even one sheet of fiberglass over the wood then putting down a pure vinyl floor to prevent any water from reaching that wood. Cost wise it might be dead even to go with a composite material IF it can provide the same suport as the ply wood.

Gunnyusmc · 08-19-2003, 09:08 AM

West Marine gives the following: 4 1/2" X 8' sheet $199.99, Wieght 90 Lbs.

Robert · 08-19-2003, 09:09 AM

I looked at the link to king plastic because I am familiar with their products. They have a foam core lightweight product that has strengths similar to plywood. I am sure it will not be cheap however.

There is an entire trend in boatbuilding away from woodcore to foamcore. Really an entire industry. The fact is you can have a stronger panel that is a fraction of the weight of ply. If Wally were still around, Airstreams would be built with it. And they would be even lighter and energy efficient.

There are backyard builders doing foam core fiberglass layup using vacuum bag to build huge panels - easily the size of the AS floor. You build on a large homemade table. Very slick.

Wrapping wood with vinyl will only trap water in the wood. You need to dry out the wood and displace airspace with resin throught the wood. Bare wood will always attract moisture. Epoxy is the trick. Search for rotdoctor.com, or raka.com. Epoxy/ply would be a good alternative to expensive composite synthetics -especially for the restorer. BTW, after cure epoxy is just inert plastic resin and the wood is sealed, so there are no issues of offgassing. An interesting concept in a vehicle that lives in the "exhaust corridors" of the world.

In the end, I still believe that floor structural connection must be eliminated. Then floor panels would just be component decking that could be easily removed for repair/replacement/access. I will sell my Airstream (at a great price) to the guy that perfects the repair.
Robert

gerbermania · 08-19-2003, 09:20 AM

Yes, plastic flexes until its yield point, similar to wood.

This attribute is typically compared using the "Modulus of Elasticity", also called MOE or just E. Generally, plywood is about 1,800,000 psi, whereas general-pupose plastics range from 300,000 to 1,400,000 psi.

Plastics can be designed to be any flexibility, so choosing one must be done based on the end use. As a subfloor, CoDemo must be supported more often than wood of an equivalent thickness for this reason. It is more flexible than wood, so it would feel more spongy without the extra support members.

The area in an AIRSTREAM where this is most critical, IMHO, is at the corners, where the floor is not supported as much by outriggers below, but it is bolted up to the shell's floor track. In this area, I would weld in another outrigger to keep the subfloor from flexing more than the wood would have.

If I were hired as an architect/designer by AIRSTREAM, I would have pushed and pushed to get rid of wood subfloors in AIRSTREAMs. The added cost of CoDemo or StarBoard is negligible, and the healthier indoor air quality, combined with the rot-resistant, more durable floor, would certainly be a differentiating factor in the travel trailer industry.

Christopher

j54mark · 08-19-2003, 11:31 AM

'the "marine" designation only speaks to the glue used...'

Actually there is a bit more to it than that. It also has no voids.

Mark

CanoeStream · 08-19-2003, 07:36 PM

When an Airstream already costs in the $40-60,000 range new, how many exotic solutions will put price in the range where only Ah-nuld will be buying 'em? Airstreams are unique in testing longevity of materials -- when a plastic box trailer wouldn't be pretty in half the time!

Rather, I suggest that it is necessary to take some interest in the systems on board. In this instance it requires periodic inspection to make sure plumbing remains intact. We are spoiled with the stability of our house pipes, but nobody tries to haul that stack of 2x4's over railroad crossings! It is a necessary part of "buying used" that inspection is important and the PO may have had their blinders on.

Epoxies come in all flavors and only certain types are intended for damp use. Marine epoxies are available but are not the panacea folks expect. I have dabbled with boat building so let me march out some facts. Cocooning in epoxy is a near impossibility in a complex structure.

Epoxy only soaks in a short distance depending on the characteristics of the wood. Epoxy set begins to restrict further absorption at some point. You can encase a piece of wood in an epoxy cocoon and the majority of wood in the center will "normal."

The coating will fail at some point under stresses of normal use. Period. I haven't even added in the penetrations of fasteners, joints and utility lines. (bonded brackets -- hmm...) Trailer boats that are taken out of water and stored dry between uses have a chance with this treatment.

Wood absorbs plenty when water is available once the epoxy layer is breached. Now the epoxy works against you, preventing evaporation and accelerating rot. Marine applications work with the characteristics of the material and epoxy is highly valuable in many ways. Vacuum bagged veneering truly would impregnate the wood, but at a high weight penalty.

I don't want to be in an enclosed trailer with anti-rot treated plywood floors (chromated copper). Even more durable woods like white oak (more axles, Andy!), Douglas fir, cedars, cypress, tamarack or redwood deteriorate in the presence of moisture and oxygen.

So maintenance and upkeep are the solution for what we are offered at an affordable (ulp!) price. Would a complex foam-cored epoxy wood laminate still be limping along after 30 years on a Sovereign? Maybe not, but it would be interesting for a while. Keep thinking, using the 'Search' function, proposing, and working things out. Fun idea!

thenewkid64 · 08-19-2003, 08:11 PM

Airstream did try something along this line in the Argosy Minuet models. Some of them have an aluminmum/foam core floor. It seems to be holding up well, but it depends on use. Some of the units have a low spot in the high traffic portions of the unit.

The Argosy line was a test bed for new ideas, that is why the 70's argosy trailers had the wrap around windows years ahead of Airstream. If you want to stay in the Airstream family, it may be worth seaching for one to replace your soverign with.

Holzarbeiter · 08-19-2003, 08:35 PM

We must remember that we are talking about trailers that are 20, 30, 40 years old.
I too have found floor rot in the back of my 78. My fix will be marine grade ply (no voids, more layers,better glue) and coat both sides with 2 part West System Epoxy before installation (We use it in upscale exterior home aplications with good results). At the seams i will use a good quality Silicone (Lexel is my preferance). I think it would be important not to seal the hole floor after the installation because the the floor needs to have some flex ( going over railroad tracks ) . The A/S is pretty well protected from from road splash so most of the water damage that we experience is from leaks above.

Just my 2 cents

smallfry · 08-19-2003, 08:47 PM

I am about a week away from putting a new plywood floor in a '57 Bubble. The frame has been repaired, painted, etc and step rebuilt, all original plywood is gone and the shin hasn't caved in. The channel at the bottom of the skin must be lighter than air because the whole skin seems to be floating.
I did put 3 coats of interior polyurethane on all sides and edges of the new plywood - exterior too offgasing my paint man said. I figure the new floor and wood wll last about as long as I do - 64 tomorrow - and that's about all I care for it to do. I want my last check to bounce - reread the "Wondrous One Horse Shay"
Jo Ann

53flyingcloud · 08-20-2003, 01:22 AM

smallfry

Let me be the first to say~!

"Happy Birthday to You~"

ciao

74Argosy24MH · 08-20-2003, 06:20 AM

Even though it is a major job floor replacement should probably be considered part of normal maintenance. Some things like greasing bearings have a relatively short cycle, this just has a much longer cycle. When I did mine I found a lot of other problems, including severely rusted fasteners holding the body to the frame and the floor to the frame, cracked welds, frame sections that were rusted through, wiring grommets no longer through the ribs, etc. Unless there is a severe leak the floor will last 30-40 years and at that point it really is time to inspect a lot of the structure and systems that normally can't be seen. These do bounce down the road and flex around so problems are a reality. It is also the opportunity to upgrade items like insulation, replace aluminum wiring, add network wiring, etc.

A forever floor is nice to shoot for, but with current technology (and the technology at the time these were built) not really possible. A proactive preventative maintence program will prolong the life of various components, but look at aircraft which the Airstream is model on, and how many times they have been torn down by the time they reach 30.

John