Roof skin replacement (I can't find 1/8 birch plywood)

[linuxmanxxx]

How can moisture get to the plywood when it is encapsulated in a waterproof glue that is adhering the aluminum to it? The glue is strong and stays flexible so it will just flex with the aluminum expansion so no oil canning happens as the expansion is controlled. The majority of installations are floated and edge screwed and there is nothing to control the expansion and contraction so it has only one option and that is to oilcan and contract. I myself have no idea why that is preferred because it causes movement and rubbing which is never good over time. I said plywood and if you notice all builders have dropped the wood based siding and almost exclusively using hardy siding due to the fact the fiber siding has always failed over time.

Lots of suggestions to garage or cover them and that would fix the problem......its a camper and imho if it can't sit outside due to exterior failures then it isn't built right to begin with. Now that doesn't mean I'm saying don't garage your TD and I want to clarify that putting one in a garage to prevent surface failures from sun and moisture isn't the answer to preventing failures.

I don't remember any complaints about failures inside a TD due to delamination except in the case of leaks so again it goes back to using materials in a way they aren't intended or manufactured for. Either pay more for wood grades for exterior or pay more for something else to cover it is the only long term solution.

If there are any on here old enought to remember a Yugo then you understand you get what you pay for in life.

[Larry C]

How can moisture get to the plywood when it is encapsulated in a waterproof glue that is adhering the aluminum to it? The glue is strong and stays flexible so it will just flex with the aluminum expansion so no oil canning happens as the expansion is controlled. The majority of installations are floated and edge screwed and there is nothing to control the expansion and contraction so it has only one option and that is to oilcan and contract. I myself have no idea why that is preferred because it causes movement and rubbing which is never good over time. I said plywood and if you notice all builders have dropped the wood based siding and almost exclusively using hardy siding due to the fact the fiber siding has always failed over time.

Lots of suggestions to garage or cover them and that would fix the problem......its a camper and imho if it can't sit outside due to exterior failures then it isn't built right to begin with. Now that doesn't mean I'm saying don't garage your TD and I want to clarify that putting one in a garage to prevent surface failures from sun and moisture isn't the answer to preventing failures.

I don't remember any complaints about failures inside a TD due to delamination except in the case of leaks so again it goes back to using materials in a way they aren't intended or manufactured for. Either pay more for wood grades for exterior or pay more for something else to cover it is the only long term solution.

If there are any on here old enought to remember a Yugo then you understand you get what you pay for in life.

Steve, Here in the cold Northern Clime we get some temperature extremes. Today it is going to be 65* and is also supposed to snow later tonight. This invites condensation. A closed TD in these extremes with or without occupants will have condensation on the walls and roof skins. TD's don't have ridge & soffet vents like houses. The vapor will rise with temperature and condense on the first cold surface which may be the inside of the outer skin. If the skin is plywood that is "interior" grade that was not intended for high humidity, there could easily be a problem from the inside, not from a leak.
Many builders use Russian Birch for roof skins. I still would like to know if I was informed correctly that RB is actually interior plywood. I agree with your Yugo analogy, that using the best materials is always prudent. 3mm marine ply is probably a better choice for roof skins, than Russian/Baltic Birch if the later is actually interior grade plywood.
The bottom line IMO is the outer surface is not the only thing stopping rot, what's under that surface has to also be rot resistant and protected from attack from both the outside and the inside. Different parts of the country have different issues to deal with. If you camp in, and store a trailer outside in cold climates, moisture on the inside will have to be dealt with.

[linuxmanxxx]

Then I'd recommend up where you guys live to install a vent cover like maxx air as standard and that way when you tow it you can leave the vent hood open and let the interior have circulating air to dry and keep it aired out. Condensation occurs when there is extremely high moisture and a cold surface and if the cabin is sealed completely and closed there shouldn't be high moisture present. Are there things like cedar chips or other things to place inside to keep humidity lowered and controlled as this really is more a winter issue than the other seasons.

On another note I found a plastics seller in the austin tx area and if you can find one locally and get some thin plastic sheeting and encapsulate the interior with it glued over the birch with waterproof glue you would eliminate any rotting issues. It is not UV resistant so can't be used externally but would make a great internal covering and easy to clean and maintain. It was $15 for a 4 x 8 for what I priced. It could be painted with standard spray paints so many colors are available to make it match your preference of color.

[doug hodder]

I've got a tear using baltic birch plywood on the exterior. All the curved surfaces are 2 layers of 1/8" birch. I also used epoxy as the glue to adhere it and it's under about 6 coats of epoxy. Automotive paint and clear coat on it. It's now 4 years old, been out in temps between 20 and 100+ and up to 6" of rain in at least 1 storm. No problems with it except the front tongue box. It filled with water like a cooler in the 6" rain storm.

A coat of CPES isn't going to do it. You need to encapsulate it in epoxy to do it correctly.

On the Nomad...the underlayment on it is also cheap luan...but I also did coat it out with epoxy prior to installing the skin on it. The skin uses no adhesive... mostly just floating, except for staples where the seams are and a piece of aluminum strip to cover them. Doug