GRP Dry-Fix Valleys - Fitting Instructions

Including Eaves Closures & Top Closures 

Dry Valley Troughs are suitable for roof pitches up to 60 degrees, and strongly recommend that plywood or timber valley boards should be used.


The underlay and battens are fitted as standard practice, with a batten running the length of the valley on each side to accomodate the external raised water bar section.

When using the Eaves Closure, the 150mm GRP pre-cut valley section support should be positioned close to the eaves.


The eaves closure should be overlaid onto the GRP pre-cut section, ensuring the Dry Valley edges are positioned over the longitudinal battens running the length of the valley.

At the highest point, fix with a large headed clout nail into the longitudinal batten.


The Dry Valley is fitted onto the valley boards and firmly fixed from the eaves closure section upwards. Using large headed roofing nails, fix the trouugh on either side, through the flat section of the water bar, at 500mm centres. All overlaps should be at least 150mm, with care taken to ensure the central raised section is not distorted, and positioned central to the valley.


If the valley finishes with a corresponding valley at the ridge, the top closure piece can be used. These closure sections overlap the valley troughs and underlap the slates or tiles that form over this point.

The longitudinal battens of each valley should meet and be mitred so that the top of the top closure can be fixed with a suitable roofing nail to stop any movement.

Tiles or Slates can now be laid into and over the valley troughs. When cutting the tiles or slates, it is important that neither should be forced to fit, in case of distortion to the central upstand. In some instances, small cuts will be required, and self adhesive packers are supplied with the valley to support these small cuts if required.

When slating or tiling is complete, the eaves closure section should be cut with a sharp knife to allow rain water to discharge into the gutter. It is important that the valley's are cleared of any debris on completion, so water flow is not impeded.










Above :  X-section of the Dry Valley - High Profile  - used with Tiles
Above  :  X-section of the Dry Valley - Low Profile - used with Slate