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Degradation of side paneling


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My 1999 Dethleffs Globetrotter is in generally good condition and everything works well.

However, I have noticed some small spots of what seems to be degradation at several places on the siding.

The siding seems to be dimpled aluminium; I don't know what the surface finish is.

They are small spots and at least one penetrated as I was able to easily put a pin through it.

I had a reputable dealer do a damp check and they found nothing wrong on the inside.

I suspect it has something to do with the fact that we live 400 yards from an estuary [aluminium outside lights on the house were trashed after 5 years by the wind blown salt].

I am hoping for suggestions as to how I can prevent further deterioration. Replacing the panels would not be worth it; maybe not feasible.

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Regardless of the damp check, ( they cannot damp check behind any cavity or double walls. ) I would be looking very carefully for damp ingress, maybe at the seams?


Salt air and rain do not go well with aluminium, if it is corrosion from the outside it may be repairable. This will be a specialist job, you need to see a specialist motorhome body repairer, they are few and far between.



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The small pin holes and bubbles of corrosion are the result of decaying wood behind the aluminium panel. As the wood rots it produces Oxalic acid which corrodes the aluminium.


The only cure is to remove the panel and replace any rotting wood behind then fit a new side panel. Any other fix will likely only be a sticking plaster until the corrosion appears elsewhere.


It is highly likely you have a leak somewhere above the affected area causing the timber to rot.



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There is a specialist motorhome body repairer nearby and he was pessimistic about obtaining matching panels.

The spots are on both sides and the rear, a long way apart.

I know rotting wood is the classic problem, but I really doubt that in this case.

Any suggestions about interim things to do? Last year I rubbed paste wax over the areas to prevent external moisture reaching the spots.

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The best post I have seen on this subject was posted by Dave Newell a couple of years ago.


Quote from Dave Newell


Being an elderly Elddis its stick built, that is to say the frame is 1" square softwood with polystyrene infill for insulation, a thin plywood skin on interior with decorative coating and a thin aluminium skin outer with thin paint finish.


Rebuilding a motorhome of this type with such extensive damp is a huge task; I know I was that soldier! I re-skinned a 1990 Autohomes Highwayman a few years back and had to reframe a quarter of the entire structure.


There are three main areas that water gets in and whichever is the one (or more) in your case will need dealing with or you'll just end up with a damp motorhome again.


The first point of water ingress is poorly fitted window seals.

Second is roof to wall joints.

Third is the worst, when water has got into the structure the wooden frame will eventually rot. Wet rot in soft woods as used for motorhome framing releases chemicals that will eat through aluminium skin in short order and will appear as tiny dots on the outer skin in line with the framework sections (often referred to as aluminium cancer).


One and two are easily dealt with but three is a bugger as it means the rotten timber will need removing and the skin replacing. Replacing the frame timbers is difficult if the damage is extensive as once you start to remove the interior or exterior skin and rotten timber the strength of the body just evaporates. I did mine one stick at a time after removing the entire outer aluminium skin (not an easy job in itself) and replaced all rotten timberwork with 1" square aluminium box section screwed together with stainless self-tappers. For the roof I fabricated a TIG welded framework of 1" alloy box section, which was placed on top and screwed to the sidewall frames.


Re-skinning was the most challenging part and took four of us three days to do the two sidewalls, rear wall and roof. Trust me when I say handling a 5 metre by 2 metre sheet of 0.8mm alloy without kinking it is not fun and spreading twenty odd tubes of sikaflex over the surface by hand is no easy job either!


Sorry if this sounds negative but I write from personal experience of a similar project. Cost wise I spent over £3K at trade prices and took nine months to do it!


Above is Quote from Dave Newell


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Good as it is, I realise Dave Newell's post doesn't really answer your question.

I don't think there is anything you can do but accept this 19 year old van is reaching the end of its lifespan. Run it for as long as its safe and legal, then scrap it. Anything else would be uneconomic. What you spend on it now is likely to be wasted when you still have to scrap it.

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