Is it normal for there to be no uprights in a motorhome? (1 Viewer)

[GagaJ]

I'm back, after a wee break. I've taken off most of the damaged ply and realised there are no uprights. The window is well framed but is relying on the insulation to support it.

Do I need to use the same polystyrene insulation and what's the black tape s for? It's under the join of the plywood and seems to serve no purpose.

I'm struggling to know what my next step is, the floor seems rotten in places, there's mould under the vinyl so that'll have to be replaced. I'm worried I've bitten off more than I can chew.

Do I finish taking off all the plywood/wallboard and replace the whole wall or do I stop just above the window?

 

[Itsmcb]

Stop when you get to good dry material or somewhere it'll be easy to hide the join. This was mine, leaking from the front corner and around the fridge vents. I replaced part of the floor but only as much as required, luckily it hadn't gone any higher.
That's the new timber and insulation you can see.
Didn't look too bad to start with, ended up with half the wall.

 

[autorouter]

Do I need to use the same polystyrene insulation and what's the black tape s for? It's under the join of the plywood and seems to serve no purpose.

It's probably a vapour barrier. When it's cold outside and warm inside, the temperature inside the wall will gradually drop towards the outside. For example, if it's 20C inside and -10C outside, then the temperature inside the insulation ramps down from 20C to -10C within the thickness of the insulation. If warm moist air is allowed to permeate through the wall, the water vapour in the air will condense inside the insulation, and in extreme cases can freeze and split the insulation.

To avoid this, vapour-impermeable insulation is used (closed cell foam, not open cell foam). However the joints are a pathway for water vapour, so impermeable tape is used to seal the joints. And also any fixings that penetrate the skin need sealing too.

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[GagaJ]

Stop when you get to good dry material or somewhere it'll be easy to hide the join. This was mine, leaking from the front corner and around the fridge vents. I replaced part of the floor but only as much as required, luckily it hadn't gone any higher.
That's the new timber and insulation you can see.
Didn't look too bad to start with, ended up with half the wall.View attachment 511967View attachment 511968

Part of the problem is that there were so many places that allowed the water in and the level varies across the van. It's 18 inches up the side of the habitation door and within 2 feet of the door, behind the fridge, there's a water line level with my eyes. I'm seriously thinking that I might have to take the whole wall out from the habitation door to the front cab. My next fun venture is taking out the untreated, unsealed, baton along the bottom that did most of the damage.