resealimg a skylight

[Stuart_374401878]

What is the best way to reseal a skylight? After being out in driving rain, I noticed a bad leak from my skylight in the WC. Water was flowing down through the screw holes. When I got back home, I unscrewed the inside plastic finish and pushed up on the skylight to release it. It came away easily and when I drew it into the van, I noticed no sign of mastic on the bit that rests on the roof. I climbed up for a look at the roof of the van and found that silicone, the type you would put round your bath was all over the place, but done in such a way that it was applied to the side of the skylight fitting. The skylight fiting looks like it should have mastic applied to the underneath of it so it is pressed onto the roof, and then the inside trim is screwed on to tighten it, forming a seal. The wooden frame around the skylight hole is black and saturated and smells of rot. I have resealed the skylight temporarily with caulk after scraping all the silicone off the aluminium skin with a Stanley knife blade. I intend going to Halfords where they are selling Carafax IDL99 Sealant for a quid a pop. Hopefully this will seal up the van and allow the inside to dry out, when I can then take stock of the damage done.

Anyone have any thoughts on the above? Are my actions correct, and are there any gotchas I should know about? Any tips gratefully received.

 

[Parksy]

Hi Stuart

Make sure that all traces of the old sealant, dirt etc are removed by using a plastic scraper, a fridge scraper or windscreen scraper would be ideal.

Clean the area using a clean rag and white spirit. Apply sealant generously into the groove that should be on the bottom surface of the skylight. Refit the skylight and remove excess sealant with the white spirit.

I used Sikaflex when I fitted a mini Heki and it remained watertight but I'm sure that other forum members will advise on which sealant is best.

 

[Damian]

Stuart, as Parksy has said, remove the roof vent, give everything on and around the vent itself and the roof a really good clean to remove all old sealer.

Using IDL 99 is a good mastic, it is non setting, so wil flex with the van movement.

Using Sikalflex is ok, until you need to replace the vent at any time,it sets and sets hard as it is a bonding mastic.

If the inside wood is black and smells rotten, then it probably is, and will need replacing.

You should find it is a frame so not too bad to replace.

Do not use any of the ordinary silicone sealers, they simply do not work well enough.