Roof valley trough change of direction where three roof pitches meet

[harrypotter]

Got a situation where I've built an extension (blue roof below) where the pitch is different to the roof it joins to. So I need to redo the valley as shown below.

Would it be ok to have the valley trough change direction slightly? I won't bend the trough, but cut a section to join it at the point where all three roof pitches intersect to run down to the corner gutter. The issue is that at the change of direction the water might overflow, but can I put a piece of plastic vertically to guide the water?

 

[noseall]

Got a situation where I've built an extension (blue roof below) where the pitch is different to the roof it joins to. So I need to redo the valley as shown below.

View attachment 314415

Would it be ok to have the valley trough change direction slightly? I won't bend the trough, but cut a section to join it at the point where all three roof pitches intersect to run down to the corner gutter. The issue is that at the change of direction the water might overflow, but can I put a piece of plastic vertically to guide the water?

Fine as long as you roof and flash it with lots of care.
This similar job...

Conv1

• noseall
• 6 Feb 2022

Conv2

• noseall
• 6 Feb 2022

...was one of the most awkward difficult jobs I've done.
My advice is to get the water off that part of the roof, as quickly as possible.

 

[harrypotter]

Fine as long as you roof and flash it with lots of care.
This similar job...

Conv1

• noseall
• 6 Feb 2022

Conv2

• noseall
• 6 Feb 2022

...was one of the most awkward difficult jobs I've done.
My advice is to get the water off that part of the roof, as quickly as possible.

Good to know thanks. That looks like a headache!

 

[noseall]

Good to know thanks. That looks like a headache!

Very difficult, yes.