Demountable camper group

So it started off as a gap below the door which I wondered why I could see daylight through,
prodding around with a screwdriver revealed very soft wood on the upright back panel to the point that it had totally rotted away & was allowing the floor to bow, I dug out a lot of foam so I wonder if there had been a botched repair at sometime previously, worrying as this unit is only, I believe 5 or 6 years old.
Anyway I started to remove the rear step to gain better access & then the door frame which revealed even more damp wood. Moving higher up past the cassette toilet & past the filler as well. Also on the other side was pretty bad.
I had to remove the aluminium sheet & all the side trip plus the mounting legs as I was worried that the fixing points had been compromised.


The construction is soft wood (very) frame with polystyrene insulation panels fitted at strategic places. The inside & outer are thin plywood with the ally sheet glued to the ply.
I hope I have all the rotten wood out now & I am starting to think about how to start to rebuild it
think I will use some marine ply thick wood treated in some way to avoid any further damp issues cut to the relevant size with the cut outs for the water filler & cassette.
The door hole will be a difficult one I think with having to hang the door frame & then mark around the wood & then cut accordingly. I think this will be easier rather than make up frames being only able to get to one side of the wood to make any fixings or joins.

Worried about the ally sheet as when removing it, it came off curled so wondering if I can flatten it I may ask a machine shop if that’s possible or may be its easier to get new & make up new panels.
Plan then to run a long checker plate 90deg bracket to fix the bottom of the back panel to the floor all along the width of the unit.

Anyway that’s the plan which will no doubt change !!
Any suggestions welcome

Sounds a plan, the only other thing to avoid this in future is 'where is it getting in' have you seen any other damp about.

What's the 'rusted' steelwork above the galvanised step?

Yes have been thinking about where is it comming from, luckly it has been stored in our tenure in our garage so only got wet when weve been out, I think this is historical judging by the mould! !!
As its worse at the bottom I wondered if its been sat on its bottom in a puddle or some such, or may be rain at a certain angle getting in around the service hatches, the top seems ok. The worst seemed to be under the door which had the ply end facing down so would guess it would suck up water if its not sealed well
The rusty iron work is actually the frame support, the step is resting on the ground underneath.

Water will find a way in almost regardless and it looks to have been doing so for quite some time I agree
where/how was it stored previously was wondering if up against a side wall or something,

knew a van once got repeatedly splashed back (upwards) with rainwater and looked similar in effect.
So are the leg mountings OK?

Rear left at the bottom underneath is a bit iffy will devise a metal plate i think after I have removed a bit more of the surrounding wood to level it all out. I will take the opportunity to strengthen up the rest.

Its a blown air heating system on yours I believe, so not leaked from heating circuit,
is it definitely rain coming in caused the damage, not something like grey water tank leaking?

No dont think any tank leaks, as we don't have grey water tank on board, just drains into an external one. Black tank seems ok as I think I would smell any issues there! !
Also too far spread across the bottom so think its rain ingress caused the problem. Will be using lots of sealent on the rebuild.

Whats the weekend plan then Mike?
have you decided the extent of the damage

Well I did cut out more last weekend will post up pic sometime soon. Just off to buy some marine ply this morning. Not sure I will get much time to work on it as my son and his girlfriend are down for the weekend so doing family stuff.
Cheers