Hi all. I've a super viking pop top and about 3/4 weeks ago I noticed that a section of the pop top has warped and in between the two hinges the side of the pop top has bulged outwards. It used to sit snugly inside the gutter line but now this section sits out beyond the gutter meaning there is far more flex when pushing the pop top inwards at this point than there should be.
I recently treated the fibreglass with some gel coat restorer. Could this be what's caused it? Or is this something that can happen to aged fibre glass? Being a super viking it's about 14 inches high so quite a bit of room for movement.
Any advice would be much appreciated as I'm keen to get it back to its original fit, although I'm a bit worried that might not be possible.
Added a couple pf pics from either end of the van that show how it's bowed out and one for the other side where the roof still fits neatly above the gutter.
Odd that it's done that in a short time- are you sure you'd just not noticed it?
Fibreglass roofs definitely flex, and over time with some load applied, they can definitely change shape permanently. I know this as my roof has changed shape from the weight of my solar panel (it's heavy), but it's been up there for about 8 years. Have you changed anything with the fixings or added anything?
There's no sag in the middle section of the roof, just the bowing of this one section.
It's definitely something that is recent and does seem to have been quite a quick change rather than a slow one over time. The only thing I've done to the roof is the gel coat about two/three months ago, but I did the whole roof so I don't think that wouldn't account for it just being this one section. It did seem to happen at the same time as the hot spell we got early on in the lockdown and I wonder whether that might have something to it?
1985 Super Viking with Subaru EJ22 (formerly 1.9 petrol DG) 1981 air-cooled 2.0 high top
I asked about pushing up in the middle because cheap grp boats can splay out if poorly designed/built. Normally there is some form of bracing glassed in, might look like ridges across the inside of the roof.
1985 1.9 DG Devon Moonraker with solid sided pop top
Personally I would suspect a combination of the hot weather and the restorer. GRP does expand and contract slightly with temp change. I would think that maybe the restorer soaked into the GRP and caused it to expand ,although only by a little, Anywhere else on the roof would be able to move freely, but the section between the hinges would be restricted by the hinges being fixed points.
I frequently carry out GRP flat roofing and have encountered similar problems although not related to applying ‘restorer’ Coincidentally I happen to also have a Super Viking.
I agree with the suggestion that it might have expanded and further more that it could be bulging out due to being restrained between the hinges. You could prove or eliminate this theory by slackening the fixings to see whether it straightens out. If this were the case slightly elongating the fixing holes could be a solution.
Were the problem was caused by tightening the over square latches while the fibreglass was softened by the treatment then one might be tempted to re-treat and jig the panels straight during the hardening stage. This does seem a bit drastic but the Carpenters twisted wooden door trick could work without the re-treatment where packing piece is placed in the door jam for a couple of days so as to twist the door back into shape.
In the case of the van this would involve springing the panels back into shape (or a bit more) i.e. together and somehow retaining them in that position for a couple of days (wooden battens and string or thin wire) in the hope that they will stay in pace once released this being assisted by the sun (fat chance ) and more likely to stay good if there is some feature to capture it like sitting inside the gutter for instance.
Well-timed silence hath more eloquence than speech.
"A quiet shy boy who took little part in games or sport"
88 High top 2.1 WBX
What do you have inside the roof pushing out or have you not put the cushions away properly? I have the Viking too and it will get this when I have all the duvets up there and when a water bottle fell down without me seeing it once!! The fibre glass skin could have also split as they seem to be moulded around a wooden/metal frame then fibre glasses from both sides. To see this take off the seal around the outside and all will show as you will see it.
Thanks for all the replies guys. A bit embarrassingly, it seems that I may well have let one of the cushions slip down and push out against the roof. I did have the roof up to check this a few weeks ago but must have missed it somehow Thanks Da dan for the nudge to look properly! I will now go and take a good long look at myself in the mirror
1985 Super Viking with Subaru EJ22 (formerly 1.9 petrol DG) 1981 air-cooled 2.0 high top
Brilliant! I’m a bit ashamed of myself for not spotting the obvious, having done the same myself previously. Guilty of overthinking and trying to be ‘clever’ maybe!
) and more likely to stay good if there is some feature to capture it like sitting inside the gutter for instance.
Thanks Da dan for the nudge to look properly! I will now go and take a good long look at myself in the mirror 
