Dormer Roof with Secret Gutter

[daz3770]

Hi gents,

I am having a flat roof built on a new dormer. There is not enough ridge height available to have a more tradtional gutter at the front edge so having to slope the roof back to ridge and have a secret gutter arrangement.

The area of the roof is 35m2 with a fall of 1:80, with the proposed gutter approx 800mm wide with a fall of 1:50. This will run off to a down pipe.

My question is, will it need a seperate/special liner for the gutter part or will the 3 ply felt system be acceptable to line it?

If not, can you suggest any alternatives?

Regards

 

[freddiemercurystwin]

There is not enough ridge height available to have a more traditional gutter at the front edge

I don't understand this bit!

 

[daz3770]

That really isn't the important bit. But the ridge height can not be raised and to get the required height in the dormer it needs to run front to back. Sealing and upstands at the ridge to prevent water ingress.

So the question still is. Will a 3 ply torch on system provide all the water proofing or will it need to be something more like a formed aluminium or grp arrangement?

Regards