5.1 Installing the first boards
Screw the start clips onto the ends of the support rails / joists. If using UPM ProFi Alu Support Rail or timber joists, predrill using a 3 mm drill bit. Install the first deck board by sliding the bottom tongue into the start clips, ensuring that the board ends are correctly aligned and that the board is lying at a right angle to the support rails / joists.
5.2 Fix the middle of the other side of the deck board with one screw directly through the bottom tongue to the support rail / joist. (for Piazza One pre-drilling is recommended, ø 3 mm). This single direct fixing of each deck board to the joist will ensure that normal thermal expansion and contraction can occur at both ends, but that the board itself stays in place. Failure to do so may result in movement of the deck boards and uneven opening of gaps. Complete the installation of the deck board by fixing the bottom tongue to the sub-structure with the appropriate clips or alu-rail screwed into each support rail/joist.