Watershed™ hardwood decking is a specially designed profile that has a slight convex curve to the upper surface and a small concave curve to the underside. It is designed to assist in the run-off of rain water from the surface of the deck which in turn reduces the risk of cupping or movement of the timber when exposed to periods of wetting. The profile also reduces the risk of slips or falls associated with water accumulation on the surface.
The system is supplied with the specially designed Watershed™ 12 gauge countersunk decking screw, available in either galvanised or 304 grade stainless steel. The system also comes with a custom fixing kit which includes a hole set out template, an adjustable countersinking drill bit, and hex drive bit.
Hermpac offers profiled Watershed™ Decking in the following species: Purpleheart, Garapa, Vitex and Kwila. Various widths and thicknesses available.
New Zealand Building Code (NZBC)
The product will, if employed in accordance with the supplier's installation and maintenance requirements, assist with meeting the following provisions of the building code:
- Clause B2 Durability: Performance B2.3.1(b)
For full installation specification please refer to Hermpac Watershed™ Decking Installation Specification document.
Using the Hermpac hole template, mark hole centre 15mm from edge of board for wide board decking (140mm x 21mm) and 12.5mm from edge of board for narrow board decking (90mm x 21mm and 65mm x 21mm) When using the Hermpac countersunk decking screws, fixings must be pre-drilled using the Hermpac 12 gauge deck drill and countersinking bit. This bit can be adjusted to drill through the decking board only and will give the correct depth for the Hermpac 65mm x 12 gauge stainless decking screw head.
Using a power driven screwdriver, drive screws into the deck surface to the correct depth. Take care to not overdrive the screw as this may result in the screw heads being damaged. Narrow board deck profiles (90mm x 21mm and 65mm x 21mm) can be nailed using an annular grooved 65mm x 3.25mm nail.
Building owners are responsible for the maintenance of the Hermpac Watershed™ decking system. Annual inspections must be made to ensure that all aspects of the decking, including substrate remain in a weatherproof condition. Any damaged areas or areas showing signs of deterioration which would allow water ingress, or degradation of the timber must be repaired immediately. Sealant and oil coatings must be maintained in accordance with the relevant manufacturer’s instructions. Regular cleaning (at least annually) of the deck surface with water and a mild detergent is recommended to remove grime, dirt and organic growth, to maximise the life and appearance of the decking. Recoating of the deck surface with a penetrating oil is recommended when deck shows signs of crazing.