Worries about Velux windows

We recently had an extension done and the roof was made of insulated panels with precut holes for the Velux windows. After the battens were fitted the roofer simply cut out a rectangle of the green Roofshield the size of the opening, nailed the Velux windows into place and fitted the aluminium flashings to all sides as he tiled up the roof. We had horrendous flooding through the window heads whist the tiling was in progress as the rain was running down the roofshield and straight into the rooms. Now the tiling is complete we've had no more floods but I'm worried that a cracked tile above any one of the windows will leave me wide open to severe water damage. The Ikea like instructions with the window show the application of a four piece felt protection before the tiles are brought up and the aluminium flashings applied.

The roofer claims what de did was fine and normal practice but is it normal practice not to provide this secondary defence against water ingress?

I'm worried that it is only a matter of time before a leak happens and wonder what, if anything can be done now to make the windows weather tight in the event of a cracked tile.

Any advice will be gratefully received Thank you.

Sounds like you mean the BFX Collar, this is an optional item and not totally necessary.

It probably leaked as the tile flahing units weren't in place and are put in with the tiling. As long as these flashings are in place (and fixed correctly) you shouldn't have a problem.

If anything goes (depending on the type of roof covering you have) it is generally the foam on the side flashings as they deteriorate over time.

SurreyRoofingEstimator said:

If anything goes (depending on the type of roof covering you have) it is generally the foam on the side flashings as they deteriorate over time.

Click to expand...

....and some installers cut the foam too short.

p.s. i concur with surrey', velux don't leak when correctly installed.

What's the function of the green Roofshield then?

I thought it acted as a waterproof layer in it's own right so that the water arising from any minor leak would run down the membrane into the gutter, rather than coming into the house.

It would seem easy to form a waterproof seal between the Roofshield and the Velux with some felt or extra Roofshield before the tiles went on to preserve the function rather than playing Russian Roulettte with the tiles above

probably the underlay has been trimmed short so there is no upstand around the frame if this is the case it will leak even if the flashings are fitted or not.

When I fitted Velux's in my old house I made sure to make the 'nappy' to seal the opening made in the felt for the Velux.

When I've had my new extension built, the roofer just cut a hole in the felt and stuck them in. It's a bit lazy, but I get the impression it's very common.

At the end of the day it's only protection against a leak through the tiles, which hopefully is a rare (or never) occurence.

Thanks for all the replies - I'll email Velux and get it straight from the horse's month.

Velux have spoken

"On page 11 of the fitting instructions there are two options shown,
option A shows the window being dressed using our BFX underfelt collar
which can be bought as an optional extra, option B shows the window
being dressed with four strips of roofing felt. Either of these can be
used to dress the window and they provide a seal between the window and the existing roofing felt.

If the window has not been fitted according to the instructions then any
problems which occur would not be covered by the warranty and would have to be rectified by the installer."

None of this was done and so I'll need to get in touch with Wyatt Earp and Doc Holliday. I'll not hold my breath!