Flat Roof Replacement

Nov 30, 2005 12 Replies

The flat roof over my attached garage is becoming due for replacement and I am considering the options. Does anyone have experience of the fibreglass type roofing that can be used on flat roofs today? It's suggested that this type, unlike normal felt, is a one-off job and never needs replacing. Is this correct?



Kev


Roofing felt/bitumen should last ten years. Fibre-glass will degrade in sunlight so will only be good for twenty years (ish) Tuf-dek or other proprietary branded 'poly-fibre-glass-plastic' roofing products usually come with a twenty to thirty year guarantee.

Price increases proportionatly. Difficulty of applying correctly also increases.

Caveat Emptor.

Choose your fibreglass company and ask to see some of their work and talk to the buildings owner.

'Swot I did

Dave

Only 10? If it's done properly, it ought to last for

*at least* 20 years, possibly 30.

"Uno Hoo!" wrote

Hahaha, very funny.

Thanks Dave - very helpful.

Kev

Yes I agree. The felt roof that I am about to replace has been on since I bought the house in 1986. It never had stones on - but rather a 'silver' coloured rubberised coating - any idea what that may be?

Kev

I very much disagree with the practice of putting chippings, etc. on felt roofs.

No idea. Sounds as if it might be a paint-on coating applied as a bodge to stop leaks.

It's a reflective layer to reflect the sun's radiation / UV. But the way, what are the stones for that you sometimes see ? They just mean the roof gets punctured when you walk on it. Simon.

UV protection?

Christian.

The chippings are required on cheaper BS747 type bitumen felt roofs in order to achieve AA rating for spread of flame. Under Building Regulation B4, any roof within 6m of a boundary needs to be AA rating. The more expensive "High Performance" mineral-surfaced felts comply with AA rating without needing chippings.

Peter

Solar Reflective paint.

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the degradation by UV radiation of the bitumen and felt.

Dave

Two reasons: Reflect the UV radiation from the bitumen/felt to prevent degradation

and Increase the surface area for the evaporation of rain water

You shouldn't puncture the roof because you shouldn't be walking on it!

If you want to walk on the roof then you should use solar reflective paint or a resinous compound top coat.

Dave

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