Newly fitted roof vent keeps leaking :(

[tmm]

2 weeks ago i fitted a roof vent and i cant seem to stop it from leaking where the vent meets the roof. I have used SIKA SIKAFLEX 512 CARAVAN SEALANT ADHESIVE still leaks i have tried tiger seal and it still leaks in. Grrr
Any advice would be great guys.

[NickJ]

Has the roof been dented from previous owners walking on it.

What vent are you using? Does it have a lip/channel to form a seal around.

I'm only using a mushroom vent it has a ring/channel to apply the sealant in. I put a ton in trying to make sure I had a continuous bead of sealand without any breaks or gaps. Once fitted I added even more to the outside before smoothing off.

I used nemesis sealant from screwfix. I have no leaks and have also drilled 15 other holes to fit my solar panels. Only thing that worries ne is recommended temperatures are between 5 - 40°c. Not sure if this is application temperature or recomended useage but we dont have a massive amount of days below zero in winter

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[chris72a]

I always use the sikaflex auto sealant or the permatex gasket maker haven't had a leak yet.

Chris

[tmm]

Has the roof been dented from previous owners walking on it.

What vent are you using? Does it have a lip/channel to form a seal around.

I'm only using a mushroom vent it has a ring/channel to apply the sealant in. I put a ton in trying to make sure I had a continuous bead of sealand without any breaks or gaps. Once fitted I added even more to the outside before smoothing off.

I used nemesis sealant from screwfix. I have no leaks and have also drilled 15 other holes to fit my solar panels. Only thing that worries ne is recommended temperatures are between 5 - 40°c. Not sure if this is application temperature or recomended useage but we dont have a massive amount of days below zero in winter

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Hi Nick
This is the one i bought

Code: Select all

[code]http://www.leisureoutlet.com/caravans-and-motorhomes/Turbo-and-Roof-Vents/Fiamma-Turbo-Vent-28-Roof-Fan-and-Vent.html[/code]

This has the channel also to put sealer on and made sure there was no breaks in the bead

[tmm]

I always use the sikaflex auto sealant or the permatex gasket maker haven't had a leak yet.

Chris

Hi Chris this is simular to what i used but mine dont seem to have worked

[NickJ]

How thick is the roof and boards etc. Are you screwing it tight enough. Not sure how this fits but i've had to pack mine to be able to screw it tight.

Are the two halves meeting up before the seal is tight enough?

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[bigjohnthomas]

as a scientist I can safety say that you've done it sh*t
take it out clean it up and try again

hope this helps
Allcock, Scientiae Baccalaureus

[tmm]

as a scientist I can safety say that you've done it sh*t
take it out clean it up and try again

hope this helps
Allcock, Scientiae Baccalaureus

Well you have probably hit the nail on the head Professor

[tmm]

How thick is the roof and boards etc. Are you screwing it tight enough. Not sure how this fits but i've had to pack mine to be able to screw it tight.

Are the two halves meeting up before the seal is tight enough?

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Yeah done all that Nick and added a frame around the inside. I'm just wondering if a frame has to be made on the outside with cutouts for the roof raised parts then add the vent to the top of the frame, if this has to be done then the vent insert ain't deep enough

[NickJ]

Are you fitting it around the raised roof sections. I'd imagine you want to find a way of fitting it to a flatter part of the roof. I've been lucky having such a small vent.

Maybe some pictures might help see where the problems might be and if any of us can help you more

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[tmm]

Are you fitting it around the raised roof sections. I'd imagine you want to find a way of fitting it to a flatter part of the roof. I've been lucky having such a small vent.

Maybe some pictures might help see where the problems might be and if any of us can help you more

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Yeah Nick its around the raised roof parts. I will get some pics tomorrow

[Beaker]

Yeah you are going to have to take it back off, clean off ALL traces of sealant, then try again.

I've heard of installers using plastic packing pieces in the dips in the corrugations on the roof to even it all up and get a flatter surface to work with. Might be worth a try.

It might not be tight enough, leaving a gap,but on the other hand I can imagine that if you over-tighten you will distort things and possibly cause gaps?

However you do it, you need an immaculately clean and thoroughly de-greased area around the vent - no sealer in the world will stick to dirt and grease effectively. Roughening the surface of the paint with a medium Scotchbrite pad is supposed to be a good idea too. Don't forget to thoroughly de-grease the base of the vent too!

And yes, when it's all squigded down, run another bead of Sikaflex all around the outside.

I'm just about to order one of these myself, so let us know how you get on!

[Beaker]

Forgot to say that the correct Sikaflex to use should be Sikaflex 521UV (Ulra-Violet resistant). They also suggest using Activator 205 to clean the area and primer 209N (for painted surfaces) BEFORE your bead of 521UV on the roof. On top of that, you are supposed to use a different primer - 206 for the plastic base of the vent.

It's nearly as expensive to buy the Sikaflex than to buy the fan! I would be tempted to use 210 Primer as it is supposed to be suitable for plastic and paint. That way you save one bottle of primer.

I know that when the guy from Vanbond (Chris Martin) came to fit my windows, he used this process: clean - de-grease - activator - primer - sealant.

I also know that the when I sealed the holes in my floor, the Sikaflex peeled up off the paint alarmingly easily, until I used some of the primer. Then it stuck like crazy.

I hope this helps.