Advice on Valley Gutter

[Don33e]

Hi All, 

 

Any advice or guidance please, our self-build has started with the porch. I have now opened up the existing roof and am struggling to work out framing (laying out) for the valley gutter the existing roof has a pitch of 45 and the new around 25. 

 

I am not a roofer, but I have done flat dormer roofs and, build simple pitched roofs for large out buildings, but I have never done an intersecting roof.

 

I have started to cut and install 19mm timber to allow 9mm ply to go on top and then be flush with the rafters is the the correct way? or could i just lay 6-9mm ply on-top of the rafters. Also I do not mind it if is lead or GRP valley gutter.

 

just looking for some detailed advice please.

 

 

[Mike]

On 23/09/2024 at 09:35, Don33e said:

I have started to cut and install 19mm timber to allow 9mm ply to go on top and then be flush with the rafters is the the correct way?

That's fine, and frequently done these days.

 

Traditionally something like a 225 x 32mm length of timber would be sawn diagonally (in cross section) to create two feather-edge boards that would be nailed to the top of the rafters, fat edge to the centre, thin edge picking up the ends of the tile battens, which is the way I've always done it.

 

Since you have plane tiles on the roof, personally I'd choose to use valley tiles, rather than GRP or lead for the valley.

[Dave Jones]

strip off more tiles to get the layboards down, then jacks off of them to ridge. klober dry valleys are excellent if you cant get hold of valley tiles.