The Corodrain D Type Universal Valley Trough is a narrow valley trough for use with single lap tiles in limited applications. There is a standard (type:HD) and heavy duty (type:DX) option. The valleys incorporate a 35mm sanded strip for the mortar adhesion. ApplicationSuitable for use on roofs with pitches from 17.5 to 55.Can accommodate a maximum difference between two rafter pitches of 15.Designed for use with interlocking tiles, can also be used with natural and manufactured slate.PropertiesLength: 3m.Width: 410mm.Weight: 2.4kg per m2.Thickness: 1.6mm.Colour: grey / blue.Material: GRP - high quality unfilled polyester resin with glass fibre reinforcement.FeaturesBBA Approved Cert No. 89/2153.UV light and acid rain resistant.At least durable as lead.Less prone to theft.Design for harsh environments or prestige buildings.Smooth surface inhibits the growth of moss & lichen and build-up of debris.Fire resistance to SAB to BS476 part 3 and Class 3 BS476 part 7.