leaking velux

9 Feb 2007
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United Kingdom
Hello, I have a damp mouldy plaster patch around one (lower) corner of a velux window on an extension roof which comes off the house wall. Definitely some water coming through around the edge of the velux, but not enough to drip - even in this incessant rain!

The roof is only 12 degree pitch, recent construction, of fake concrete "stone slates", with plastic felt underneath. The "slates" above and around the window are in good condition and appear well laid, the flashing at top of the roof (joining the wall) looks good too. So hopefully the felt is dry (tho I can't be sure).

However the "slate" the velux lower flashing is lying on is only about 5 degrees - almost flat. Sticking my finger under the bottom flashing its damp in there. The location is very sheltered so no driving wind.

Is there a product to attempt to seal under the flashing, or other quick fix to try? Should I really be taking the "slates" off to diagnose the problem properly?

Secondly, is this something I can reasonably have a go at - I'm a DIY enthusiast but never done anything with roofs or veluxes. There isn't a safety issue because the extension is dug into a bank - the bottom of the roof is ground level. Or is this really a job for a pro? If so, is that a general roofer or a velux specialist, if there is such a person?

Thanks very much for any advice, Phil.
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velux windows and their flashing kits are virtually fool-proof provided the instructions are followed carefully. i would try and obtain a copy of the fixing instructions and re-do the job properly.

the other thing is, the velux window may inadvertently allow in water, that has run down the felt from a fault further up the roof.
Just bought 2 Velux windows with flashing kits and im pretty sure it says the minimum pitch they guarantee them for is 15 degrees so maybe this is the problem?
If it is the problem im not sure what the solution might be..Velux have a flat roof product but i havent seen it so cant comment whether it will work in your scenario.
Do you have the correct flashing fitted? I seem to remember a post from last year and the pics showed that they'd used a slate flashing on tiles (or vice versa)
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Thanks for the replies - hmmm, I'm not feeling good about this as a DIY job, I think I'll get a pro to look at it.

I know a roofer who's done work on our (real) stone slate roof, I will call him and see if he knows about veluxes.

Thanks Phil.

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