Roof Dry Valley Construction

Water collects in a valley to flow off the roof.

Roof dry valley construction. Either lay tiles dry or bed on mortar onto fibre cement undercloaks laid loose on each side of valley ensuring a minimum 25mm gap between mortar and the tilt fillet. The valley area of a roof the straight lines formed when two different planes of the roof meet is a critical area that handles a tremendous amount of water run off. Alternatively a tile and a half may be used to avoid small cuts of tile. The pitch of the roof here is 35 degrees the untiled main slope of the roof is 45 degrees.

For an open valley a sheet of metal usually steel sometimes copper is fastened to the roof deck. Additional eaves closure pieces and counter battens are not required and they create a close cut appearance. No one but you can decide which kind of valley you want for your roof. Installing a close cut grp valley with redland 49 tiles.

In the latter case where the insulation follows the rafter line there are many different ways of constructing the roof. The metal is usually pre painted to best complement the shingles color blend. Woven closed cut and open. Essentially there are three main ways to shingle a roof valley.

In this situation the bridge piece is placed in position to support the smaller cut tile section. Many of these warm constructions include a requirement for counterbattens below the slating or tiling battens. Roofing shingles are installed then cut and sealed where they overlap the metal channel. Redland dry valleys are suitable for both traditional cold roof and warm roof construction.

Also keep in mind that at times open valleys are prone to storing water and thus causing roof leakages. While making a decision about that do consider factors like cost then entire look and of course the functionality. In many ways the roof construction for a pre formed grp valley is the same as that for a lead lined valley. The dry valley mitred at the ridge and awaiting the final tile course.

It is therefore worth asking the valley manufacturer for guidance on this. Dry fix valley troughs are mortar free providing hidden water gulleys at the roof valleys. If your roofing contractor can he will get rid of the metal which means you don t have to pay for it while installing a roof valley. Cut tile and a half tiles neatly and fix to form a gap minimum 125mm wide centred on valley.

Valleys are typically found where gable dormer roofs meet the main roof or when a house has angled wings or additions where two roof sections in different planes meet. Some grp valleys are sufficiently robust to enable them to be laid directly over the rafters rather than being supported on valley boards.