Extension roof design - valley + gutter help

[craig1234]

I have attached a drawing showing an extension I am about to build (brick section of house). I am compiling my building regs drawings and would appreciate some help on the roof design. What I would like help on is the valley design i.e do these need to be constructed of code 4 lead on ply and if so what sort of dimensions do I need i.e depth, width etc. Also, at the base of the two hips (I think this is the correct term) again, do I need to construct a gutter (is this the correct term) from lead or are there pre-formed "gutter" sections available that I should use? Thanks

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• craig1234
• 20 Feb 2011
• 1

 

[Regencyroofingipswich]

The width of the box gutter will be determined by the pitch of the two roofs but ideally you would want to be getting 600mm + to stop it blocking with leaves and to give you an easy access for maintenance.

It should be an 18mm plywood construction and stepped up 100mm at every 1.2 metres length so you will end up with sections of lead at around 1.5m which is the maximum span allowed or else it starts to split when it flexes with heat.

Lead would be a minimum code 5 but if you are after the best use code 6.

 

[craig1234]

Thanks Recencyroofing.
I did construct a box gutter a year ago for a porch but it seemed to be a lot of effort/mucking about. This is why I wondered whether the gutter had to be constructed of lead or whether there were pre-constructed metal/plastic gutters available (for the valleys as well I guess). are these available?

 

[SurreyRoofingEstimator]

There are other routes such as single ply membrane systems but TBH lead would be your best bet as will last as long as the building (if carried out correctly) and is easier to detail