Surface PreparationThe surface should be reasonably clean and dry if the
Watco Adhesive Mastic is to be the only means of fixing. Badly dished or holed concrete etc. should ideally be filled. Watco Adhesive Mastic will take up minor undulations and imperfections.
If application is to damp, dirty or friable surfaces or in very cold weather, use Watco Adhesive Mastic to bed the GRP item into place and then always screw fix. Screw fixings are generally made at about 600mm intervals. Drilling through the GRP is easy using a standard twist drill suitable for wood or metal. Countersinking is not required.
If you need to cut the GRP product, a good quality abrasive disc, jigsaw or hacksaw can be used. The GRP material is quite tough to cut by hand, so if power tools are not readily available, please ask about our cut to size service.
Fixings
If mechanical fixing is required, the following may be used as a guide:
To timber: No.8 x 30mm zinc plated or stainless steel screws.
To steel plate: No.8 x 20mm self-tapping pan head Pozi stainless steel screws or No.8 x 20mm self drilling pan head Philips zinc plated screws.
To concrete: No.8 x 30mm zinc plated or stainless steel impact anchors (Hilti HPS-1 or similar).
To open mesh: Stainless steel or zinc plated saddle clips and domed head bolts suitable in length for the depth of the existing treads.
Application
Lay the items in place to ensure that they fit. Trim using a jigsaw with medium cutting blades (Bosch TI01 AIF or similar are ideal).
Hold the GRP in place and drill holes approximately 50mm in from each edge and thereafter at approximately 300–400mm intervals through the panel and into the substrate. A rawl plug will probably be required in a concrete base. The drill hole in the GRP does not need to be larger than that drilled into the substrate.
