Leaking flat roofs

[gaz1234]

Hi
I’ve a flat dormer window (top floor) that has been leaking for a few months (think it’s been like it before we bought the house) and had a few people have a ‘quick’ look at it before the leak was bad. Nothing really came of those views as I had other jobs ongoing.
Today I’ve had someone come over to say they would put grp over the top of what’s already there. Guarantee it for 10yrs.
Would this be a good fix? Temp, poor or avoid?
The thinking before was to just replace a couple that look in need (bowing, have flash band repairs) which including scaffolding was 5/6k plus. There are 5 in total, 2 bad (bowing and holding water) 1 suspect, 1 unknown (next to the leaking one) and the leaking one itself.
Someone else was suggesting epdm (rubber). I got the feeling fiberglass should be best?
Any suggestions?
cheers

 

[^woody^]

Does it need a new roof? Or repair?

New liquid coatings can be applied over some firm stable existing coverings, but not over any old crap.

A 10 year warranty is useless unless it's insurance backed. He can give you a 1000 year warranty and then go bust or change the company name after he's had his tea that evening.

 

[gaz1234]

I’ve had one look at day repair. The others have not looked inside just outside and have suggested replacing as I’ve one that’s bowing/holding water.

He said it’s fibreglass on there currently.

 

[^woody^]

If the roof is bowing and ponding, that's an issue with the structure, and just coating it with anything won't rectify the ponding.

That said, ponding itself if not a problem and not a cause of leaking if the covering is sound.

So beware of being advised to recover the roof to cure ponding. You need to avoid giving a firm the job to cover and then have them start and say they need to strip the roof and fit new timbers and decking at extra cost

A fibreglass roof cover should be lasting about 15-20 years. If it does not need replacing entirely, it can likely be repaired - but the repair needs to be properly diagnosed and located.

If you want to rectify the ponding, you need a quote to strip and fit new timbers and decking. And doing that means insulating too.

Be sure of what work and outcome you are being quoted for.

No system is best. Firms will only claim that the particular product they fit is "the best". Someone who is trained to fit a liquid system won't fit EPDM. Felt roofers hate any modern alternative.

IMO, EPDM gives the most cost effective and longest performance. I specify that nowadays, unless there are lots of things like plant and rooflights, in which case a liquid product may be preferable - but only for that single reason.

 

[gaz1234]

Felt roofers you mean fibreglass?

 

[datarebal]

Torch on felt, or single ply Alwitra all the way