DIY flashing on homemade rooflight.

[Deluks]

Ok, I'm building a shed and intend to put some kind of rooflight in there. I have a 100cmx50cm DG unit minus frame, which I'm going to build into the osb roof, sitting slightly proud. Whats the best way to flash this?

I have some roofing lead knocking about, but was thinking more of using self adhesive flashing tape. Whats the best way to do it? Roof will be felted soon, but in the next 6 months will be underneath a corrugated pvc lean to, so this will only be a temporary solution.

 

[oilman]

.............. Whats the best way to flash this?

Remember water is influenced by gravity, except when the wind blows.

 

[Mw Roofline]

Have done this DIY job myself on mates roof. I used some stuff called Butyl Flashing. We use it on conservatory roofs etc, sticks like dog **** to carpet. Its colour is pvcu white so looks nice on the frame.

I don't suppose you are near to Wolverhampton, West Mids, I can give you our suppliers address.

Matt

 

[Deluks]

Sounds good, do you mean this foilband stuff?

I can't find it at a price worth paying, for a shed roof. (I am in London btw)
I may as well go with something like Evostik flashband, supposedly lasts 15 years but I only need it to be waterproof for about 6 months. In time uv damage will be more of any issue TBH.

Has anyone used the Screwfix flashing tape?

Do I want to raise the highest part of the window above the roof surface, to encourage water to run 'around' it?

Or do I make it lower than the roof to make the water go over the flashing and down the glass?

Obviously I make the lower part of glass higher than roof surface.

 

[Mw Roofline]

Sounds good, do you mean this foilband stuff?

Yep, its kinda like that. Cheapest I can get you is £5 a metre plus postage to London.

 

[Deluks]

Cheers for the offer, but still a bit overspecced I think.
Wickes do a 10 metre roll of 150mm stuff for a tenner. Enough for the job plus some spare for emergency repairs. I know to be wary of Wickes own brand stuff but it's probably made by a reputable company and rebranded, like a lot of their stuff.

What about the window though? (previous post)

 

[Mw Roofline]

Do I want to raise the highest part of the window above the roof surface, to encourage water to run 'around' it?

I would have thought this method. I'm sure the Wickes stuff will work. Ours is so expensive because its thick, a five metre roll rolled up sits about 11" wide (with a 2" centre tube though)

 

[MHoppy]

Foilband is EPDM based and will not turn plastics to dust most other tapes like flashband blackjack and own brands will turn polystyrene, acrylic and even polycarbonate to dust - I have seen the results when specification has been ignored to save a few quid

 

[noseall]

If you have to use a tape flashing, do as Mw Roof has said and go for a white, thick butyl type as it will be less prone to influences from sunlight etc.

The problem with flashband is it does not deal with movement and temperature changes very well. It is likely to split and/or peel away.

For the window you are best lining the cut-out with say a narrow rebated door casing allowing it to stand proud of the roof surface by a couple of inches. The run-off side (bottom edge), trim the rebate so that it allows the water to run away and not gather.

Trim the outside of the casing with some angle fillet.

Bed the glass into the rebate with silicone, then lap the flashing tape up onto the glass.

 

[joe-90]

He's just told you it's a flippin' shed and he doesn't want to spend money on it. I used Flashband on a cheap conservatory and that's still fine 10 years on.

 

[freddiemercurystwin]

Not to mention Deluks thread is 3 years old!

 

[noseall]

Not to mention Deluks thread is 3 years old!

 

[vinty]

If you are felting the shed why don't use felt flashings, if i am felting a flat roof using torch on felt and there is a skylight on the roof i just torch on flashings around the upstands of the skylight frame.