alternative to lead?

[calvert]

I am having a pitched roof (approx 35 degrees) fitted with a parapet wall running along one edge (about 14 metres) so it will need a gully. Is there a cheaper alternative to lead for this job please?

 

[redtonybbb]

Tony B.(EX Roofer /Chartered Surveyor).
Hi,
Built -up Felt is probably the cheapest option.With this being 14m long joints for the lead would be required.Alternatives include Grp/aluminium.single ply membranes.If felt is used make sure the tails of the roof tiles do not sink into the felt/via heat and puncture the felt.It is better to allow for a timber roof batton laid loose in the eave just to carry the weight of the tails of the roof tiles.Also if felt is used it is better to use a small lead cover flashing to weather,rather than trying to manipulate felt into joint or placing beneath coping stones.The problem is with felt it does not last as long as lead,but may be coated in solarflex paint to keep the sun off.Felt may be better in some areas where the lead is accessable and often removed by theft.

 

[calvert]

Thanks very much Tony, lot of info. Would you expect the felt to last as long as on a flat roof (15 or so years?)

 

[Xenon]

Decent felt well installed will last for years. Extend the layboard to at least 200mm, and if not to high, take felt over wall then bed copings on it.

 

[calvert]

Thanks. I presume I can use a cold system for this

 

[Xenon]

Thanks. I presume I can use a cold system for this

I haven't seen a decent cold system in 25 years where felt is concerned.

I would not DIY something as critical, and difficult to access as a gutter, bite the bullet and have it done right if you want it to last.

Liquid Plastic is another alternative, but again needs pro install.

 

[redtonybbb]

Thanks very much Tony, lot of info. Would you expect the felt to last as long as on a flat roof (15 or so years?)

Hi-Normally the felt in a gutter to a parapet in generally more shaded,therefore the life expectancy should be around 15 yrs.It is generally accepted a built up felt roof will be guaranteed for ten years if done correctly,however that is not to say up to 20yrs lifespan or slightly more may be achieved on occasions,and even then there are now modern substances that may be coated on top of the older felt(not generally accepted as good practive)which ill waterproof the gutter.There are even substances out now which can actually seal in the wet.(and I don't advise to get these substances on skin as they are a real problem to remove)good luck. remember 1.5m lengths of lead cover fashing code 4 is ok with 50mm or 2inch lap over the upstand as a minimum.use lead wedges as necessary(and point in 1:3 cement mortar).

 

[calvert]

Thanks very much for all the good advice. I feel confident now

 

[Xenon]

Thanks very much Tony, lot of info. Would you expect the felt to last as long as on a flat roof (15 or so years?)

Hi-Normally the felt in a gutter to a parapet in generally more shaded,therefore the life expectancy should be around 15 yrs.It is generally accepted a built up felt roof will be guaranteed for ten years if done correctly,however that is not to say up to 20yrs lifespan or slightly more may be achieved on occasions,and even then there are now modern substances that may be coated on top of the older felt(not generally accepted as good practive)which ill waterproof the gutter.There are even substances out now which can actually seal in the wet.(and I don't advise to get these substances on skin as they are a real problem to remove)good luck. remember 1.5m lengths of lead cover fashing code 4 is ok with 50mm or 2inch lap over the upstand as a minimum.use lead wedges as necessary(and point in 1:3 cement mortar).

I think you're a bit out of date.