Available in 3 height options, the traditional dry fix valley trough is suitable for use in tile and slate pitched roofs. The traditional dry fix valley has options to suit high profile tiles, low profile or plain tiles and slate tiles. PropertiesLength: 3m.Width: 370mm.Upstand height: 80mm.Thickness: 2mm.Roof pitches: 17.5 to 22 - 350mm lap.22.5 to 29 - 300mm lap.30 to 39 - 200mm lap.40 to 49 - 150mm lap.Weight: 3.6kg per m2.Material: GRP.Colour: grey.Fire rating: SAB to BS 476 Part 3 Class 3 to BS 476 Part 7.Installation guide1. Valley boards should be fitted of sufficient width to provide support for the roofing battens, either: min. 12mm ply lay boards set between rafters, or 6mm continuous ply boards laid over the rafters.2. A single strip of roofing underlay should be laid up the centre of the valley.3. Counter battens the same depth as the roofing battens should be fitted onto the valley boards.4. The main roofing underlay should be laid over the counter batten. Roofing battens should be fitted with the ends firmly located onto the valley boards, positioned close to the counter batten, with care taken to avoid damaging the underlay.5. The fascia board should be cut to allow the GRP valley trough to pass through and discharge into the gutter without flattening out. The end of the GRP valley trough should be trimmed using a fine toothed hacksaw to the appropriate centre line of the gutter - which normally entails a v shaped cut.6.The GRP valley trough should be fitted with care taken to ensure it is centrally located between the valley boards - the sides should be nailed to the counter battens at max: 500mm centres.Lead replacementGRP lasts as long as lead, is tougher, cheaper, more resistant to accidental damage, and is less prone to theft or vandalism. Using preformed GRP valley troughs saves significant installation time over traditional methods. Roofers report elimination of many problems with valley troughs when changing from lead to Corodrain GRP. Coloured lead grey as standard (other colours available on request).