Best stuff for sealing a leaky flat felt-covered roof?

[Drake]

Can anyone advise what is the best stuff for sealing a leaky flat felt-covered roof?

I once used some black bitumous liquid from B&Q, but the leaks recurred after about 2 or 3 years.

Thank you,

Drake

[Vass]

a tiled sloped roof

[Bob Mannix]

Or even a new felt covering. This is the minimum solution once they leak. Factor the cost in your plans for every 10 years.

[Dave Plowman (News)]

It really depends on why it's leaking. If a seam etc has failed it can be repaired. If the felt is crumbling replacement is the only real cure.

[Drake]

Thanks. I saw no signs of crumbling felt when I last applied bitumous sealing liquid a few years ago. But I'm really not sure where the leak is, precisely. It could just be a small split that's very hard to locate. All I know is the roughly 2ft x 2ft area where the leak is located.

Drake

[Drake]

That sounds like a good solution, actually. Thanks...

Drake

[Drake]

Yes, I couldn't agree more. My only problem is the cost and time it would take to construct.

Drake

[John Rumm]

Strip it all off, and re-felt is the only real answer to that question. If you keep fixing it, there is the problem that you may not stop all of the leaks. So when you do eventually strip it off you are faced with the possibility of replacing loads of rotten timber as well (and ceiling joists if its dry rot you find!).

In spite of its poor reputation, a felt roof can last well if it has a good solid base and at least three layers of quality felt that are bonded on with hot tar.

[Dave Plowman (News)]

The cost of doing this could exceed several felt roof replacements - even if it were practical to do so. On many flat roofs - like extensions - it's not due to windows etc above on the main building.

Flat roofs generally have a poor reputation due to poor design and construction.

[Drake]

Thanks. I'm sure that would be the most long-lasting solution. But I'm really just looking for a quick fix that will last at least a few months. I don't intend to be living here much longer than that.

Drake

[Drake]

Yes, the above all applies in my case, as it happens.

Drake.

[robgraham]

I used that bitumen faced Al tape successfully to solve leaks in several flat roofs. No doubt it has a proper name but it is available in the sheds.

Rob

[John Rumm]

flashband? (toolstation do a cheaper version - available in a number of widths)

[David Sims]

Have you considered replacing with

?

[chris French]

In message , Drake writes

Well in that case, and given that you say you know the general area of the leak. how about a big patch of felt over that area, stuck down with the paint on bitumen glue type stuff?

[John Rumm]

Or a roll of "torch on" felt and a big blowtorch. Quick and easy to fix and that will effect a repair that might even last a few of years.

[Andrew Mawson]

Ironic really, as when looking at properties with flat roofs, they are referred to as 'duck ponds' by surveyors, but I suppose where you find ducks you find Drakes

AWEM

[Drake]

That sounds like what I need. Thanks. Can you tell me who sells it? B&Q? Wickes?

Cheers,

Drake

[chris French]

In message , Drake writes

Might be in your local DIY shed, any Builders Merchants will sell it though I imagine. (Note to all felt is suitable for 'torch on' application)

As for the torch, probably best off hiring one.

[Dave Plowman (News)]

They're only ever duck ponds if actually flat. Which is the problem. I can only assume most builders want the work of replacing badly made ones as it hardly costs more to put a proper slope on them.