How To Install A Grp Roof Valley

It is good practice to lay a width of underlay along the valley and then overlap the general underlay on each side of the valley over this.

How to install a grp roof valley.

A roofing expert points out the important details for the valley when installing roofing membranes. In order to shingle this kind of roof valley a roofing professional has to install both roof faces at the same time which is quite slow. Soup to nuts riley shows the proper way of installing a valley on a roof. More information on tyvek roofing membranes http www c.

The contraction of the grp in cold weather can tear the underlay apart at the laps in the valley trough units. Grp valleys have pre formed upstands to prevent the ingress of water and for mortar bedding some have integral sand strips to ensure a good adhesion between the mortar and valley lining. Lay a strip of membrane down the valley 100 cm wide is ok. A woven valley shingle installation has other drawbacks including that they are slow to install especially in cold weather and more difficult to repair than the other types.

It is therefore ideal if the underlay under the valley is not bituminous and is laid over the valley battens along with the main roof slope underlay. Grp does not streak or stain and we offer a 30 year service life guarantee for all our grp flashing products so you can be safe in the knowledge your roof will remain leak free for years to come.