Traditional nails or screws used to secure decking-boards create vertical holes, which allow moisture to penetrate into not only the decking-board, but also the joist below.
Trapped moisture in these vertical holes; and also between the deck boards and the joist, will lead to rot and ultimate failure of the deck. Deterioration of the timber will also cause the nails or screws to loosen their grip.
As Sharkstooth is fixed horizontally into the side of the joist - not the top, there are no vertical holes for water to access. Sharkstooth also creates a gap between the decking board and joist allowing proper ventilation and preventing moisture build-up.
Timber swells when wet and shrinks back when dry. This can mean a change in plank dimensions of up to 7%. The amount of shrinkage and swelling is dependent on the type of timber, the moisture content at installation, and the climate where the deck is built.
This movement creates a lateral force to act upon the nail, working it loose and reducing its ability to hold the decking boards securely. As the timber shrinks back, the nail hole is enlarged. Shrinkage causes the board height to drop, exposing the head of the nail. The nail is now effectively loose in the hole and moisture can penetrate the timber. Traditional fastening systems were never designed to cope with the cyclic effects of swelling and shrinking of the timber.
Sharkstooth holds decking boards more securely than traditional nails or screws, thus minimising movement. Fixings are on the side of the timber and loads created are horizontal rather than vertical. This means forces from traffic / movement are absorbed laterally and the fasteners are not worked loose. Sharkstooth allows decking boards to move naturally without compromising their hold on the timber.
Cupping is caused by the drying effects of the sun generating an extreme force. The top surface of the board being more exposed to the elements will shrink faster than the bottom. The sides of the boards will then begin to lift and the force this creates can become too much for the nail or screw, pulling it out. This is known as cupping. The nail then loses its grip on the joist, allowing further ingress of water. The empty nail hole fills with moisture, which accelerates the rotting process. Popped nails are a sure sign of a failing deck and once the grip from the nail has been lost, the decking is free to twist and lift at will. Complete failure of the deck has now occurs, creating a major safety hazard - especially for young children.
Sharkstooth however, will continue to bite into the timber and hold it firm throughout the seasons. Cupping is reduced in two ways: Firstly, the ventilation gap allows the top and bottom of the board to dry evenly. Secondly, the teeth penetrate into the side of the board and maintain a positive downward force.
Twisting and lifting of the boards does not occur.
