Pitch of lead valley

[bucketsFull]

Hi there,

Used this site so many times to get really helpful information but this time I can't find the answer to my question anywhere so thought I'd try asking direct.

I have a lead lined gully (6 metres) in the middle of my butterfly/valley/London roof. It seems to me that there is pretty much no flow in the gully and so it often "pools" water for extended periods. So far the lead is water tight.

Some roofers have told me that the whole things needs to be replaced (basically a whole new roof which is currently fine!) because of the lack of slope to the gully, others say it's perfectly acceptable and the "open end" at the back will allow the water to drain out as it fills.

Which is it and what to do if it does indeed need more of a slope?

Thanks all who have informative words.

 

[Alastairreid]

others say it's perfectly acceptable

There is your answer.

 

[bucketsFull]

Is there any sensible way of increasing flow (more for peace of mind than anything). For example could you fit some sort of lining on top of the lead at the start of the run to raise the level up?

I should add that the reason this could be an issue is because of leaf fall in the area blocking up the valley over time.

Thanks again.

 

[Alastairreid]

You cant raise the valley without stripping either side to form the upstands..there isnt a quick fix!

If it was mine i wouldnt give it a second thought tbh.

 

[bucketsFull]

Fair enough. I guess the real problem is how do you clear leaves from the valley? Roofer has suggested a guard over it but I'm thinking that it might not play well with snow etc.

Is there no other way than periodically getting up there? Perhaps a hatch is the expensive but long term solution?

 

[yorkie1969]

Hi there,

A lead gutter only needs to have a fall of 1:80. Therefore 1 inch fall over every 80 inches of length. Many flat roofs hold water to a degree but as long as they have been installed correctly that is not a problem. A correctly installed lead gutter will outlast any other material so it is not a good idea to cover it with something else. Just clean the leaves out a couple of times a year whether it be by putting up a ladder or installing a velux window adjacent to the lead gutter.

If it would set your mind further at rest why not post a few good quality photo's of the gutter so one of my learned colleagues or I can see for ourselves and comment more.

 

[bucketsFull]

Wish I could but unfortunately I currently have no access to the roof.

The roofer I've spoken to has suggested a modern rubber covering for the parapet and party walls as opposed to render and coping stones. Is this a sensible solution if done properly?

Thanks again guys.

 

[Alastairreid]

I cant see a properly rendered parapet wall being out performed by rubber or whatever he wants to stick to it.

 

[bucketsFull]

Thanks alastairreid,

I questioned him a bit more thoroughly and unsurprisingly he has now lost interest in the job.

I have decided to go with new rendering, flashing and coping stones. The total perimeter (2 party walls, one parapet) is around 16 metres. The brickwork and existing flashings are leaking in a few spots but only in heavy rain. The modern slate roof is new and no problems.

I am getting quotes for this work from 3.5k right up to 6.5k. Is it me or is this very high?

 

[Alastairreid]

Seems a bit OTT especially the 6.5k even if you are in London.

Get more quotes making sure they specify exactly what they intend doing and materials being used.