damp - can I make wallboard or a substitute

[hawaiisteveo]

hi guys

I have discovered extensive damp in my 1994 Swift Corvette.

I'm keen on doing a DIY repair but the wallboards are quite expensive. is it possible to make walllboards from polystyrene and plywood? how do i go about this?

I havent got a clue what the internal structure is like yet. I'm afraid to start poking around just yet until ive done a little bit more research

thanks

Steve

 

[hawaiisteveo]

hi guys

I have discovered extensive damp in my 1994 Swift Corvette.

I'm keen on doing a DIY repair but the wallboards are quite expensive. is it possible to make walllboards from polystyrene and plywood? how do i go about this?

I havent got a clue what the internal structure is like yet. I'm afraid to start poking around just yet until ive done a little bit more research

thanks

Steve

Read more at http://www.practicalcaravan.com/forum/new-members-say-hello/51376-damp-can-i-make-wallboard-or-a-substitute/edit/401178#0jBwJhCleERTWDqT.99

 

[Gagakev]

Hi steve welcome to the forum.

The construction of the walls are already polysyrene and ply, you have an outer skin of aluminium (most likely)
with the polystyrene sandwiched in the middle with the ply wall board internally, the frame is appprox 25mm X 25mm battens and thats it, the wallboard is not that expensive Take a look here

You can also have a Look here at arepair I did on a Abbey a few years ago. The photo's show how it is put together, good luck.

 

[hawaiisteveo]

that's a great job Kev.

is wallboard basically 3mm of ply plus vinly/wallpaper?
was the polystyrene bonded with the frame, the alluminium skin, the wallboard or a mixture of the three?
thats a fantastic price for wallboards. i spoke to a local caravan sales business in northern ireland who were quoting me £100 per sheet of wallboard that had bonded insulation.
I take it my van doesn't have bonded insulation and I could go for wallboard and bond some polystrene or failing that ply and alluminium (not too concerned about having a van without a wallpaper / vinyl covering the walls. at 20 year old i'd be happy with a varnish

 

[ProfJohnL]

Hello Steve,

I don't know the specific construction used in your caravan, but certainly around 1994 all teh manufacturers were experimenting if not using bonded construction systems. where the aluminium outer and the foam filler and the internal wall board were all glued together. THis might be important as such a construction would have given strength to the components. If you do try to do a DIY repair I strongly suggest you do attempt to glue all the layers to try and restore some of the rigidity to the structure.

 

[hawaiisteveo]

Thanks John,

I was hoping that would be the construction as it seems pretty straightforward to replicate. polystrene, plywood or wallboard and glue between everything

 

[Gagakev]

Thanks John,

I was hoping that would be the construction as it seems pretty straightforward to replicate. polystrene, plywood or wallboard and glue between everything

Steve make sure you use a non solvent glue....dont want to melt the polystyrene!!
A liquid glue is better as the tube (mastic type) can go on too thick and you get an uneven spread.

 

[Sproket]

Have a look here at the glue people who specialise in adhesives for your kind of repair, when i repaired my floor i used there delamination repair system you can buy all sort's of different types of adhesive but do make sure that whatever you choose is suitable ....

 

[hawaiisteveo]

thanks guys.

just checked out soudal fix all and its solvent free.

its surprising how much more difficult it is to do this job in Northern Ireland.

everything has to be ordered through and i'm getting extortionate delivery charges.

its largely why i'm going with 4mm plyboard rather than wallboard,

soudall fix all seems to do everything but how good is it on a caravan exterior?

 

[Gagakev]

thanks guys.

just checked out soudal fix all and its solvent free.

its surprising how much more difficult it is to do this job in Northern Ireland.

everything has to be ordered through and i'm getting extortionate delivery charges.

its largely why i'm going with 4mm plyboard rather than wallboard,

soudall fix all seems to do everything but how good is it on a caravan exterior?

Look Here

It states indoor and outdoor, water and weatherproof, but as said earlier would not use it to bond the ply and polystyrene, it is too thick and would go off before you could spread it.
I used it for another repair on my current van which was around the wheel arch. but that was a small area compared to wall repairs.
Follow up Sprockets link to the glue people, and get a liquid one.

 

[hawaiisteveo]

Thanks, much more confident using this now and I'll definitely look into the liquid glue

 

[redjeff1980]

I am a carpenter and was going to repair a caravan before I realised it was too far gone. I managed to pull off a wallboard with the aid of a scraper without damaging the polystyrene. You a get lucky and do the same!

 

[hawaiisteveo]

Hi Red Jeff

I fear mines may be the same I have found rot in the floor just under the walls. This might be a list cause.

What was it that gave you the sign it was too far gone?

 

[redjeff1980]

Well I knew mine needed a lot of work anyway as I was given it for free because of the damp. I had assumed it was just the front of the caravan that needed work as the rest looked in decent condition.
The problem with damp is that it spreads and although what looks minimal damage can be quite extensive. I soon realised that once I had started to strip back the wall boards, the damp had ventured into the rest of the timbers down the caravan. It was then a case of having to remove the kitchen units, wallboards and section of flooring.....something which I wasn't prepared to do due the cost of materials. It was a real shame as I would of enjoyed rebuilding it, but why spend so much money repairing it when, at the end of the day, your still left with an old style caravan.

Yours may well not be that bad, either you start removing panels to see the extent of the damage or you sell it with known damp.
If you can push your finger in to the damp spot and you make a mark, the damp is considerably bad. If the timber still seems solid then it's probably not that bad and you have caught it early....that's worth finding the leak and sealing it, the wood will soon dry out without the need to strip out the interior.

 

[hawaiisteveo]

That's exactly what I have been weighing up. I bought ours last year for 900 and I haven't used it just yet. It came with a lot of new extras which were hardly used so repairing it could see the family for 5 years of hol's.

The way I see it is that a newer van could cost a fortune and develop the same problems. I reckon I could get the materials for about £300 to fix the lot.

 

[hawaiisteveo]

Got it on Gumtree and didn't know it had damp. First time caravanning so didn't really know what I was looking for in terms of structure

 

[redjeff1980]

It really depends on what materials you need. If you need flooring then you will need sheets of ply top and bottom ( aprox £20 per sheet) and then the insulation between them. You may need window rubbers which is usually sold in 20 meter lengths, so enough to do your whole caravan I suspect, these are around £200. Your wall boards and insulation you may need (£40 per board the last time I checked). You will need to remove your awning rails and reseal with silicone, so you have the sealant cost (aprox £12). And this is just to repair the damp, not including any other general repairs the caravan might have.
If the caravan doesn't look like it's got damp or it doesn't look that bad, maybe you could reseal the outside and use the caravan as it is? The timber will dry out eventually, just depends if it has turned to rot.

 

[hawaiisteveo]

Hi Jeff.

I was going to plyboard and vinyl wallpaper the plyboard. Plyboard £8 a sheet for 8 x 4, polystyrene sheet £6.50 a sheet same size. The window rubbers are the dearest. I think it'll be 150 including delivery and then of course mastic and soudal fix all.

As you say though, its time and finishing up with a 20 year old van.

Pride wants me to keep going and the thought that I could have a practically new van afterwords. New frame, new insulation, resealed, new window seals etc.