Disaster management - skylight leaked ceiling ruined


Free Member
Hi all first post need a bit of a shoulder to lean on hope that's okay!

Basically, last week I noticed a slightly creased patch in my van one evening on the veltrim where it meets the ceiling. Touched it, and thought it felt a bit funny. Started touching around it and all was dry. Eventually, I summed up the courage (apologies for the slight drama here) to actually press on it and to my horror it felt wet. Got a bit of paper towel pressed it and confirmed that when I saw the paper soaked. Popped out the screw driver, took the bug screen off the skylight and saw the batons were absolutely soaked and starting to develop mold. So at least I located the leak (well, there is only one hole)

Thankfully this weekend I managed to replace the skylight. Originally I actually pointed it with Stixall which I was lead to believe was excellent. The stuff peeled of very easily to my alarm and I remember two years ago properly preparing the surfaces with spirit before laying the stuff. So I think people should seriously stop using that sealant for exterior jobs. But before I digress the new one is on as good as I'll ever get it. All surfaces on the new skylight gently abraded, roll mastic used to create a level surface (rather than just Sikastromer gunk) edging all done and cleaned up after the screws tightend (the mastic seeped out under compression) to finally point with Sika 512 (not Stixall never again) it now truely looks like a thing of beauty not a rush bodge at all. This is a do-or-die job. It it fails I'm done.

Which leaves me with the ceiling. When I popped off the ply, the celotex behind was absolutely soaked. All the pillow insulation inserted in the ribs was soaked and rusty too. Unfortunately, behind the insulation and against the actual metal of the roof was drenched. So I've had to completely strip down the ceiling. Seeing how the damp was so evenly distributed across the surface area of the ceiling, I'm wondering if some of the wet was actually caused by condensation at least in part. I feel as if I really do not want to use celotex again, it was a pain to fit originally and no where near panel-perfect fit (due to the bowed roof) it's just disheartening because I was under the impression that I was doing all the right things with the best products and techniques I could. All the sheets were foil taped to try and create a vapor barrier etc. Pity.

So I'm currently looking alternatives here, ideally a chap to professionally spray foam it with the closed cell stuff. Any thoughts or recommendations in Gloucestershire region or I can travel!

Any idea on price too?

Thank you
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Full Member
I do not think that your problem was condensation - it was the rooflight sealing. Provided that you dry everything out ( put a dehumidifier in the van for a couple of weeks if you can) you should be able to reuse that Celotex and replace your roof lining. Please do not become dispirited. Good luck. Geoff.


Full Member
You have to control the movement of air around and under the insulation. Any spacers or battening needs to be waterproof or they can become waterlogged. Also make sure all your insulation are waterproof. Filling the pressed steel ribs with expanding foam should help too, just make sure it’s closed cell. I’ve just found a similar problem and am going to have to replace all the roof insulation and coverings.

Millie Master

Full Member
Actually I believe one of the core issues is condensation caused in part by the void between the Cellotex sheeting and the inside of the vans roof.

The OP @motorshieve mentions using "spirit" to clean the roof prior to using the amazingly brilliant Stixall, I hope that wasn't white spirit as that will do anything other than clean a surface as it always leaves an oily deposit that no adhesive will stick to. Personally I use meths to clean any and all surfaces before using Stixall and I know others use far more expensive products but can't recall what they are.
The rooflights on my 'Millie' are stuck on with Stixall (after I had experienced some poor results with Sikaflex) and they have been firmly in place now for getting on for 5 years of extensive touring.

As for spray foaming, unfortunately you won't get many if indeed any professional outfit very excited in only spraying the relatively small roof area so it might be better to think about doing it yourself using one of the kits that you can find on eBay or similar, but if you do go down this route make absolutely certain to heat the tins of spray foam up to the designated temperature and then only apply it very quickly in the thinnest of coats each pass as otherwise the heat generated by the chemical curing of the foam can and will cause panel distortion.



Full Member
Anything subjected to moisture will absorb it if it can. Treating before installing any woodwork would make sense.
Right, so it’s a question of preventing ingress (I.e. paint, stain, varnish) rather than stopping it rotting (e.g. PSE treated timber). I see....thanks

Though I don’t think I’ve ever seen a blog etc where anyone does that! I suppose using exterior grade ply for battens, which I have seen, would be one way of doing it. But most people just seem to use regular timber.


Full Member
Exterior grade or marine ply is rubbish. Caught that bad cold :( Any framing of an aperture I will now use Buffalo board. The stuff used for truck beds. The wet room in Murky is lined with the stuff after the marine ply failed. The plan was to cover it in vinyl after watching it for a few years, but never got around to it.


Full Member
If you have a look at Greg Virgo build videos he has a couple on insulation, that is his day job I think. It shows some spikes with strong sticky pads that you peel and stick to the roof/walls etc then push the insulation panel on. You then push clips on the pins to hold the panels tightly in place, bend over end of pin and cover in Ali tape to complete vapour seal.
Looked simple and neat solution for holding insulation in place to me