Waterproof Airstream - Impossible?

[Jim & Susan]

I am 100% convinced at this point that wood is absolutely the wrong material to use on the floor. Nylo-board or those composite floors in the early Argosys are the way to go. They do not rot, at least in the same way that wood does. If I have to replace any more floor parts, I'm going with Nylo, regardless the cost. I helped another forum member install Nylo in his '74 last year. No rot yet.

jim

[perryg114]

Sorry about the new rot. You must have some leaks you did not catch the first time. I am chasing leaks in the front of mine and I am getting rid of the gap between the C-channels. I am also putting in drains so water can get out of the C-channel. I am also trying to make the C-channel water tight by putting Vulkem over all the screws and floor penetrations. I already replaced the floor in the rear of the trailer and so far so good. I did not have time to add drains on the rear section but I am adding them to the area to the right of the door and up between the batteries. I am not sure where I am going to stop with the renovations.

Perry

Originally Posted by Jim & Susan

Hi guys. There's no such thing as a water-tight Airstream. Doesn't exist, never will.

When I ripped the floor out of ours, I followed the generally accepted wisdom on the forums for treating the new floor before it went back in. I used West Marine epoxy around the first 6 to 12 inches against the wall/c-channel/u-channel (including the edges). The rest of the floor got two coats of verathane. t\The bathroom was entirely coated on the top side with epoxy before the vinyl floor covering went in. This was six years ago (damn, I'm getting old).

We now have rot in several places on the new floor, but I hope it's not "fatal".

The roadside radius area up front has a leak that is pretty serious. Given all the precautions I took to seal the floor, I can only surmise that i drilled thru the seal at soem point, causing a route for water into the wood. Result is black rot in the new wood. Under the galley, there's another leak, but I think that was is from the intake/exhaust for the old heater. This one is not too serious and can be repaired fairly easily.

That dang bumper area, on the other hand.....That wood in the new floor is just about shot directly under the rear hatch. The weird part is that it just sneaked up. I never noticed any problem until last fall when I reached in there and noticed the new wood was brittle. This one will have to wait until the winter rains stop and it warms up a little. One thing is certain, tho. I ain't pullin' that bath back out to fix it. There'll be a new way to do floors invented before I go thru all that again.

BUT YOU KNOW WHAT? I'VE ALWAYS WANTED AN AIRSTREAM, AND NOW I HAVE ONE THAT IS FUNCTIONAL. And after 4000 miles of towing it all over the southeast, it's still intact, warts and all.

Keep it in the road, boys and girls and all will be fine. Our 'Stream will be 40 years old in September. Not many people can say that.

Jim

[Gene]

I agree the plywood Airstream uses is not good, perhaps well sealed plywood would work. But the problem is the way the trailer is built at all the penetrations. Cars and trucks rarely leak. They use rubber seals and while the rubber eventually hardens, cracks and has to be replaced, it lasts a long time. Airstream could do the same. Perhaps vinyl could be used as a seal also.

Gene

[Jim & Susan]

Originally Posted by perryg114

Sorry about the new rot. You must have some leaks you did not catch the first time. I am chasing leaks in the front of mine and I am getting rid of the gap between the C-channels. I am also putting in drains so water can get out of the C-channel. I am also trying to make the C-channel water tight by putting Vulkem over all the screws and floor penetrations.........

Perry

Did these things myself as well. The only thing I can figure about the front radius area is that I drilled into the new floor from the outside while reinstalling the belt line trim, allowing a path to the new wood floor. More Sikaflex along that trim is n my future, I suspect.

Jim

[reinergirl]

Originally Posted by CrawfordGene

. In a few days it will be warmer and I could run some duct tape along the outside to keep it sealed until it is warmer I can use the proper sealant. The problem with that is it is a pain to remove the glue, even with the usual way, WD-40.

Gene

Gene,
If its only temporary why not use aluminum tape? Works well and comes off much easier.


Jim, I am horrified to hear of rot in a 6 year old supposedly well protected floor!

I wonder if the problem was in that the wood was coated both sides? My dad was a expert woodworker (built a mahogany gaff-rigged yawl that was gorgeous!) but I remember him saying on many, many occasions that wood could get wet without harm as long as it could dry. The problems start when it can't dry out. By creating a wood sandwich with a waterproof layer on top and bottom, the water has no chance to evaporate and thus rots the wood. Regardless, the West System should have protected the edges as it is supposed to sink in and make the wood impervious to water. Sigh

[Gene]

Reiner, your father was right. The problem is whether the wood gets enough air to dry out. If you can coat it everywhere, it should be ok until water finds a way inside. I hadn't thought of aluminum tape—thanks!

Jim, when you coated the floor, were you coating the subfloor in place and trying to get as much sealant against the inner wall as possible? I would think something thin would get further in there—perhaps urethane—but that's because I think of epoxy as viscous.

Gene

[Jim & Susan]

I coated the outer edges with epoxy before they were installed inside the camper. The leaks most certainly occurred after everything was installed.

[Wabbiteer]

Aluminum tape exposed to weather died in weeks or a few months here - I'd used it to cover the belly band holes to keep water sheeting past the plywood, never again. Not only does the aluminum heave, shrink, wrinkle & tear, it will oxidize and become difficult to remove as the adhesive hardens on the shell. I'm not sure what to recommend but foil-style duct tape self-destructs.

[dkottum]

"My dad was a expert woodworker (built a mahogany gaff-rigged yawl that was gorgeous!) but I remember him saying on many, many occasions that wood could get wet without harm as long as it could dry. The problems start when it can't dry out."

And that is the problem with installing a vinyl floor covering on the plywood. I would prefer stiff highly-breathable carpet sections in a low, tight weave that could be easily removed for drying, cleaning, or replacement.

doug k

[bhutch74ly]

Originally Posted by dkottum

"My dad was a expert woodworker (built a mahogany gaff-rigged yawl that was gorgeous!) but I remember him saying on many, many occasions that wood could get wet without harm as long as it could dry. The problems start when it can't dry out."

And that is the problem with installing a vinyl floor covering on the plywood. I would prefer stiff highly-breathable carpet sections in a low, tight weave that could be easily removed for drying, cleaning, or replacement.

doug k

I agree that it is important to use a type of floor covering like carpet (iwthout waterproof pad) that will allow the plywood to "breathe" or transfer water vapor to the air inside the trailer. Furthermore, I believe it is important to provide as much ventilation of the airspace as possible to remove the moist air and dry the floor as quickly as possible after it gets wet. I'm also wondering if it's a good idea to seal the upper surface of the plywood with epoxy, urethane, etc. for the same reasons. If the plywood is getting wet at the edges near the outside of the sidewalls or under the C channel, sealing the surface may only delay drying. Of course, if the plywood is getting wet from water falling on the floor inside the trailer that's a different matter and sealing the surface of the plywood should be helpful.

I recently bought my 25-footer in Arizona where it sat outside in the weather for many years. To my surprise, the subfloor was in excellent condition with only a couple of small areas with water marks and very little soft/rotten plywood. It's been in Louisiana about two months now and the flooring in several areas has been wet ever since it arrived at its new home in spite of my ongoing efforts to get everything caulked and sealed. This weekend we had several inches of rain and the wet areas have grown significantly! Perhaps I should move my trailer back to Tucson and leave it in a lot there? If not, I probably need to build a shed for it real soon or it's going to melt down on me. Based on my observations and the comments in this thread a shed appears to be the best way for me to deal with the water problem for the long term. If it gets wet while we're vacioning, I'll just remove the carpet, open all of the cabinets, turn up the heat, plug in the fans, and get it dried out as quickly as possible when we get back home.

[perryg114]

The floors tend to rot in the end cap areas. On my 81 the straight sections have a different extrusion. The ends of the plywood are cradeled in a channel. This helps protect the wood from leaks that would soak the end grain of the wood. Plywood will suck up water like mad through the end grain. On the end caps that channel is missing and they go back to using regular C-channel and the edges of the wood are right underneath that belly band. The banana wraps cover that area but I have seen places where the wrap was on the outside of the skin which would funnel water right into the sub floor. The floor in my 30 yr old trailer is in decent shape accept for these end cap areas and a problem area to the right of the door. Anyway it is a really good idea to cover the exposed ends on the plywood with Vulkem to help protect from end grain water intrusion. There are gaps where the straight section meets the end cap C-channel. Any water in the C-channel will end up on the floor in these areas.

Perry

[Gene]

So, aluminum tape and duct tape don't work, but I'll have to find something. I have to check what temps are ok for the exterior sealant too. Sealing and not sealing the plywood each have fans. My thinking is that plywood can get wet on occasion and dry out, but chronic dampness and water over time will eventually cause it to deteriorate no matter how much ventilation there is. Vinyl will create a vapor barrier, but the planks I will use will have a 1/4" gap around the edges and can be lifted up from time to time to check the floor. Carpet lets the subfloor breathe, but also wicks water down to the subfloor. Laminates often require a vapor barrier underneath because they deteriorate if the substrate gets wet.

The best floor solution would be to leave the subfloor exposed, or replace it with something that can't absorb water, paint it and use that as the floor. I doubt anyone is going to do the first, and few will do the second.

I'm not going to remove every penetration of the body and install rubber gaskets before I put them back, but that would be the way to go I think. If I ever start my own RV company, that's what I would try, but the chances of me starting an RV company are pretty low. And I'm not going to remove and replace my subfloor with an impervious product, at least not as long as the OEM one is ok. By the time it fails I will probably be too old to fix it so I'd better make sure it doesn't fail.

Once the snow melts, I'll probably use duct tape on one side of the door trim because it will take take a couple of months before it starts to fall apart and reseal that area when it is warm enough to do so (unless I can do it at 35˚ or 40˚). I'll use a couple of coats of exterior polyurethane on the floor and thin it enough so it will flow under the inner skin—I'm not sure that will work, but I'll try it. I'll have to be more careful about keeping up with re-sealing all the penetrations. The nature of the new floor means I can check the subfloor from time to time. I'm sure my approach isn't perfect, but I don't know what else to do. Now I'm glad Airstream uses the cheapest vinyl they can find, because if I hadn't decided to replace it, I wouldn't have known about the leak and the damp spot.

I never thought I'd have to think about all this when we started looking at Airstreams—I thought it was like a car or truck—made of metal and sealed properly. So many surprises in life….

Gene

[Aerowood]

As all of you may or may not know I have been using my GT as an aluminum tent for several years now. Not because I'm lazy but my flying schedule seems to be in the warmer maintenance months. Anyway I can honestly say that I am "LEAK" free at this time, it has been a long road fixing all the leaks, and that I am almost done with just 3 more window frames to do. I do believe I have identified all the previous leak sources and it has been a long list that can be attributed to a short list of causes. Airstream construction techniques is the main cause. Not a single lap seam had a faying surface seal but just a fillet seal. Nothing was installed wet with sealant. The window frames are installed with a foam seal that wicks water as it gets old. The access doors and cavities behind them is an open invitation for moisture intrusion.
So what have I done differently? I have opened all the lap seams and injected a very high quality sealant in between the the skins and shot it back together. I have decreased the rivet spacing to give a better sealing contact between the underlying structure. I have tied the internal framework together for a more unified structure that does not twist or flex as much as it used to. No matter how you seal everything up, if the structure moves around to much it matters not a bit how well it is sealed as the seal will fail. I have removed the windows (almost all) and removed the foam seals. I have replaced all the sheet metal screws that penetrated the exterior shell and replaced with sealed anchor nuts. One of the biggest leaks fixed was to install the banana wraps and side wraps under the exterior skins instead as they are installed now acting as a water inlet scupper.
So have I gone a little over the top with everything I have done so far, most likely. Is my approach for the average Joe, most likely not. The point I.m trying to make is that of all the issues I have run into, is that 99% could have been accomplished at construction with a minimal cost increase by the manufacture, if they would just have recognized a deficiency in their construction processes years ago.

Is condensation for me still an issue, you bet it is, but if you give a path for any moisture accumulation to exit then you are ahead of the game. I do like Perry's idea for the drain tubes in the lower C channel to exit the water into the belly pan so it can drain out, I will do just this. It is also my opinion that the condensation is only caused when we are using our silver bullets and has no way to exit and dry when parked, so allowing for drain paths and a minimal amount of airflow would be of a great benefit. By the way, every Aircraft I have ever worked on has drain holes in the belly for just this purpose, but they do have the added benefit of having differential pressure to ventilate and help the condensation drain the airframe, but the drain paths are all over the inside of the fuselage and is part if the inspection procedure to keep them open.

The access doors are going to leak no matter how good of a seal is on the door, that's just the way it is and should be accepted. The issue here in my opinion is to concentrate on sealing up the cavity behind the access doors and allow a path for the moisture to exit. The cavity itself should be completely sealed off from the inside of the trailer and waterproofed, then it doesn't matter if it gets some water in there as long as there is a water exit path and minimal ventilation.

[reinergirl]

I'd like to see a picture of these drain paths in the c channel and a detailed explanation of materials and whether u attempted a slope or ? Any one care to link?

[Aerowood]

Perryg114 I hope you don't mind but I copyied your idea and picture and posted below.

Here is Perryg114's idea

[Ridgerunner3]

Has anyone tried treating the perimeter top (approx 6 - 10") of the subfloor with CPES penetrating epoxy as a rot prevention measure? It seems that this could be done fairly easily with the shell on and the floor covering removed.

[dkottum]

One of the reasons Airstreams leak through even a pinhole opening is the air pressure is lower inside than outside when the wind is blowing rain, or it is moving down the road in wet weather. Its like water being sucked through a straw.

Auto's don't leak in this manner because there are forced air vents and fans keeping relative interior air pressure higher than outside.

In addition to sealing, which can be quite futile because you'll never maintain the necessary perfection, what can be done to create a positive air pressure inside the trailer?

doug k

[Aerowood]

Originally Posted by Ridgerunner3

Has anyone tried treating the perimeter top (approx 6 - 10") of the subfloor with CPES penetrating epoxy as a rot prevention measure? It seems that this could be done fairly easily with the shell on and the floor covering removed.

Yes I have done just as you said but I used thinned poly first before installing the new subfloor then used thinned epoxy later on. The thinned epoxy found its way under everything and really wicked in. I used 3 coats and the wood absorbed it like a sponge.

[Gene]

Originally Posted by dkottum

In addition to sealing, which can be quite futile because you'll never maintain the necessary perfection, what can be done to create a positive air pressure inside the trailer?

doug k

Our trailer came with two Fantastic Fans only set to exhaust. I rewired one of them to make it an intake fan. Running it alone, or at a higher speed than the exhaust fan should create a little higher pressure. It is supposed to be ok according to FF to leave the vent door open while traveling, but we've never done that. I don't know if this would create enough air pressure to keep water from entering at the penetrations of the exterior skin.

Since there are three places where there are doors—fridge, water heater, and furnace—there's a source of outside air. I would not want to do anything with the last two, but the fridge compartment is pretty big and propane fumes may not be a problem. A vent with a fan that pushes air into the trailer might be possible if it can be kept away from the chimney. I'm not too excited about this idea because of the propane issue.

Another way to get air in is behind the rock guards ("segment protectors"). They protect from rain and splash pretty well and a vent with downward facing fins could let air into the trailer when traveling. A smaller vent in the rear could provide flow-through venting and some positive air pressure.

Gene

[perryg114]

No I don't mind at all. I have installed these drains already in the section between the door and the nose. I used 3/8" thinwall stainless steel tubing and flared the end of it. I used a wood countersink bit to flare and clean up the hole a bit. I coated the inside of the hole with parbond and then put Parbond around the outside of the pipe flare and stuck it into the floor. It sticks up a little bit but it is pretty close to flush. I also made a little gutter to the right of the door to funnel water below the skins. Anything that comes down the right side of the door frame ends up under the floor. I have sealed all screws with Vulkem so they are not a leak path. I am going to wet test by pouring water into the C-channel just to see where it goes. The biggest problem is some rivets are drilled a little too close to the bottom of the C-channel. This provides a leak path. I may Vulkem those low rivet holes and drill new ones higher on the channel. I am in the process of painting the floor under the battery boxes. They are not there right now. I am just using Latex right now. It is not as good as Epoxie but it is better than nothing. Last fall, I painted the whole subfloor with latex to seal off the stains and other nasties that were under the carpet. I would have used polyurathane but that stuff takes a long time to dry and for the smell to go away and I did not have time before we were going to use the trailer. The gray floor paint looks pretty good compared to the stained and nasty sub floor. I did use urathane on the section of floor I replaced but it could dry outside in the sun.

Perry

Originally Posted by Aerowood

Perryg114 I hope you don't mind but I copyied your idea and picture and posted below.

Here is Perryg114's idea