Leaking dorma roof / velux?

[Poindexter]

Just looking for a bit of advice and direction on this ongoing problem.

Basically bought my house last year - knowing there had been water in the roof of the dorma extension (has a flat roof joining a small pitch with 2 identical velux windows side by side) water falls from a lowered beam section inside the room, the beam joins with a flat ceiling one side and slopes up to the top of the velux windows the other side (around the top of the slope which joins the top of the velux has flakey paint and underneath the paint the plaster looks damp/darker) - the lady selling the house had the flat-roof renewed before we completed and we assumed that would be that.

Anyway the next heavy rainfall with wind etc (3 months on) it happened again - so the roofer came back, said the flat roof was fine and that is might possibly be coming in the side, through cracks in the cement of the ridge tiles and so fixed those......next heavy rain fall with wind etc it happened again! (2 -3 months later)

Got a new (recommended) roofer in and he thinks its coming from the ill fitted drainage system inbetween the top of the 2 velux windows - i agree it could be this because water at present can freely run down behind it.

I guess my question is, is this a common fault with velux windows and is it possible for driving rain to get in above the velux windows between the tiles and the velux (we have a gap there you can fit fingers/flat hand into) - what can you do to protect this gap, do velux do anything for this?

Please note, we don't get any water in on normal rainfall - just when it gets a bit more stormy! Sorry its so long winded and thanks for reading.

 

[bikerm4]

what type of slates or tiles are on the roof? is the roof underfelted?

 

[Poindexter]

It's a tile roof, textured to the touch, with a curve type shape in them - yes i believe the roof is felted underneath. We've had constant rain for the last 24-48 hours and no drips - its definately when the rain is driving in....

 

[masona]

I guess my question is, is this a common fault with velux windows and is it possible for driving rain to get in above the velux windows between the tiles and the velux (we have a gap there you can fit fingers/flat hand into) - what can you do to protect this gap, do velux do anything for this?

Only a common fault if it's not done correctly, can you do a photo?

I've been one job that has roof leaking a couple of year, took me while to find it and it was the wind lifted the lead flashing on the side and push in the rain underneath because the lead code was too thin, upgrade the lead flashing now it's okay.

I think your problem could be not when it's raining, it's which way the wind is blowing.

 

[bikerm4]

It's a tile roof, textured to the touch, with a curve type shape in them - yes i believe the roof is felted underneath. We've had constant rain for the last 24-48 hours and no drips - its definately when the rain is driving in....

sound like mendip tiles. I have seen similar problems with stone slates because of the different thicknesses and with some tiles because they dont compress the foam strip on the top flashing enough and water can be driven in in windy exposed situations. In these situations i have pushed some foam pipe insulation between the tiles and the top flashing to prevent the water being driven under by the wind.

 

[Nige F]

It's a tile roof, textured to the touch, with a curve type shape in them - yes i believe the roof is felted underneath. We've had constant rain for the last 24-48 hours and no drips - its definately when the rain is driving in....

sound like mendip tiles. I have seen similar problems with stone slates because of the different thicknesses and with some tiles because they dont compress the foam strip on the top flashing enough and water can be driven in in windy exposed situations. In these situations i have pushed some foam pipe insulation between the tiles and the top flashing to prevent the water being driven under by the wind.

Foam lagging Reminds me Years ago Marley waterproofing developed a sticky foam -cell strip that expanded when fitted to (expansion joints) building situations.may still be around/better

 

[Poindexter]

^^i like the foam idea - may give it a go.....the new roofer is coming next week - see if he can see any problems on the actual roof when he has a proper look under the tiles etc.....if not - its got to be this gap.