With this heavy duty 4m high structural mezzanine floor we opted for the 32mm shutter ply decking allowing us to have a larger span between supporting joists. Generally when using the 32mm thickness boards we would use a 610mm spacing as the board size is 2440 x 1220. With the 21mm board we go down to a 488mm spacing. It is essential to give the board enough support underneath especially when loading items with a heavy point load as in the case with shelving units. When there is a heavy machine on top of the floor with few legs then it is always advisable to spread the load of the machine by adding bigger steel plates under each foot.
This is a welded system where the rigid steel IPE joists are welded directly onto the main bearer beams. It is sometimes better to use this method for heavy duty installations as the IPE joists can span a longer distance than the lip channel joists with limited deflection. This mezzanine floor was designed for a 450kg's/sqm load and stacked to capacity of full steel shelving units. We also installed a hinged gate in the hand rail for easy access to load items with a fork lift.