Trex Composite Decking Calculator.

At TJ O’Mahony.ie  our Trex composite decking boards are all 16-foot-long (That’s 4.88 metres)  

Our boards are 144 mm wide and 22mm thick.

The recommended gap spacing between boards is 6mm side to side.    

This is guide to calculate roughly how many boards you will need for the main area of your deck.   

You may need additional boards for vertical areas, steps, angled patterns & flower boxes.

Calculations provided for boards installed at a 90-degree angle. If laying boards on an angle,

an approximate increase of 15% may be required.

 

So how many of our Trex Boards will you need? 

Imperial feet (old school) based on the 16ft boards.

Multiply your deck length x width to calculate your square feet area. Now divide by 7.3.

Example   Your new deck is 16-foot-long by 15 wide.  

16x15 = 240 square feet.  Now divide by 7.3   =  32.87 -  So say 33 Trex boards.

 

Metric metres.  Based on the 4.88 metre boards.

Multiply your deck length x width to calculate your square metres area.  Now divide by .69

Example  your deck is  4.88  metres  long by 4.572 metres wide.  

4.88x4.572= 22.311 square metres.  Now divide  by .69    =  32.87 -  So say 33 Trex boards.

 

Some important points about gapping and spacing

As daily temperatures change, all deck boards will expand & contract. Therefore, it is essential to install the boards with gaps as recommended below by Trex. The size of the gaps required also depends on the temperature in which they’re being installed so please check the official Trex Installation guide PDF

All deck boards must always be installed with a 6mm side-to-side gap. The Trex Hideaway Hidden Fasteners will automatically measure the 6mm gap between grooved edge boards but you must still ensure the 6mm gap with the square edge boards.

All deck boards must always be installed with a 3-5mm end-to-end or end-to-width gap between boards.

There must also be a 6-13mm abutting gap between the boards and other objects such as garden walls or houses.