Part 3 of the four part guide to roof construction covers pitched roof detail.
Pitched roof valley gutter detail.
The lowest course of tiles slates should not touch the roof membrane.
Where the roof pitch is between 8 12 5 the.
Valley gutters are generally considered to be a problem area.
Part 1 a guide to roof construction covers an overview of flat and pitched roofs.
How to do a roof valley martin s roofing and guttering merton ltd for all your roofing needs.
Cut underlay to rake and dress over tilting fillets to lap onto metal valley.
The valley gutter problem areas can be made worse where there are surrounding trees and associated leaves and branches that can block the valley gutters up.
A valley gutter is where two main roofs meet or where there is a change in roof direction.
Maximum catchment areas for valley gutters are given in table 8 of e2 as1 for minimum roof pitch and gutter widths.
It is an area where water is directed towards rather than away from therefore correct detailing and construction is essential.
First clean the debris out of the valley including sawdust nails and whatever else is in there.
A common misconception is that the mortar bedding is there to prevent water access.
Where a flat roof adjoins a pitched roof or where valleys or gutters occur the waterproof membrane should be carried up under the tiling to a height of 150mm above the flat roof valley or gutter and lapped by the roofing underlay.
Ensure that underlay is not laid under metal.
To get the most out of it is helpful to also read parts 1 and 2.
Cut tile and a half tiles neatly and fix to form a gap minimum 125mm wide centred on valley.
Cad details document name pdf dwg download all cad construction details 37 1 mb 3 4 mb mc01 identification of roof areas 694 kb 167 kb mc01a single layer underlayment 678 kb 302 kb mc01b double layer underlayment 711 kb 322 kb mc02 vent pipe flashing 626 kb 349 kb mc03 valley.
Ensure that valley boards plywood sheathing and tilting fillets provide full support for metal valley.
Roof ridges and ridge tiles roof hips and hip tiles roof valleys roof verges and lead flashings.
Purpose made valley trough tiles should be supported by gutter boards where the roof uses single lap interlocking tiles they should be mechanically cut to the correct rake adjacent coverings should be neatly cut to form a smooth junction and preferably be cut from tile and a half tiles.
Catchment area must be no more than 25 m gutter must be at least 250 mm wide.