Research and Development

A small deck was built in July 1998 and exposed to Brisbane’s climate to study the process of deterioration of timber joists. A variety of materials and fixing methods were used for the study and the following result is a perfect example of what happens to uprotected joists.

TEST

Materials used: Joist: F14 hardwood with oil based primer painted on top.
Decking: Mixed hardwood
Fixings: 50mm bullet head ganvanised nails.

RESULT

After 5 years 7 months the deck was cut through for the first inspection and photographed. The photo clearly shows a split in the joist measuring 30mm deep, (to the point of the nail). Towards the base of the split there is a shade of green caused by trapped water penetrating the timber. At the top, the split has opened up spreading the joist and swelling has caused a convex on the top of the joist.

The level of deterioration after such a short period of time was far beyond our expectations. This test result reinforced our commitment to complete the development of Joistrip and make it available as a real solution for eliminating such a major defect in timber deck construction.

WATERPROOF TEST

Pieces of Joistrip were stuck together with a sealant to form a dish. A variety of fixings including, 50mm Galvanised Bullet Head nails, 75mm Treated Pine screws and a 100mm Batten screw were used to penetrate the rubber flashing. Water was then poured in to test the effectiveness of the seal around the fixings. A large sheet of white paper was placed underneath the so called dish to detect any drips that might appear.

These photos were taken several weeks later finding the original sheet of paper unmarked...NO LEAKS!

It also proved to be a very good result for the sealant.

Needless to say we had to constantly top up the water due to evaporation.