Valley Trough?

[kkuss]

Hi, I'm re-roofing my house and also constructing an extension. My problem is that the existing roof pitch in 17.5 degrees and the extension pitch is 35 degrees. I'm worried that the difference in pitches will force water into the existing roof via the shallower pitch unless the lead valley is very well constructed? I came across 'Valley Troughs' this morning and they look to be more suitable for what I need. Problem is my (old) builder hasn't heard of them before.. Are they what I should be using? Rgds Gunther

[[news]]

if it's made from fibreglass steer well clear. code 5 lead will last 100+ years

my solution for a similar problem was to neatly seal the edges of the lead/slate interface with leadmate. whoever owns the house in 20 odd years time may have to rake it out and redo it. but by that time the roof will be 120 years old and it will probably need re slating anyway so it's not a big problem.