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Low-level composite deck over concrete and soil

Building a Reputation
Building a Reputation


A backyard composite low-level deck with lights built over soil compacted with crushed rock. 



The project


I always wanted to have a deck over our alfresco area since we moved into our new home. Our alfresco is only just about 10sqm, so I decided to double the size and make it 20sqm by extending the deck past the concrete slab and over some soil. I used composite decking and some decking lights around the picture frame border. This is my first big D.I.Y. project and I'm happy how it turned out. 


I learned that if you do all the preparatory works properly, things will be easy along the way. I prepared the soil by levelling it and compacted it with crushed rock. 




I also marked every corner to keep everything square.




Also for materials, I used 90 x 45mm treated timber for my joist and tuff blocks for my frame footing. I have about 180mm ground clearance to work with but due to the weep holes I had to lower the deck a bit. So tuff blocks, 90mm joists and 23mm boards gave me a total of 163mm ground clearance, which is what I needed. 



I only used a circular saw and did not have any issues. I use a rafter square as a saw guide when cutting. As I don't have a long clamp to hold the boards, I used tie down straps instead. This really helped me hold the boards and keep the gaps the same all through out. It's a bit tedious removing the straps and putting it back each board, but it worked for me. 



I also added two noggins near the centre of each joist to add stability. 




The front of the deck is actually the separation between our alfresco and the fire pit corner that I plan to build soon. I’m planning to put geo fabric on top of the sand and put some stepping stones along the path. Then maybe fill the area with decorative pebbles. 

The stormwater drain is still there. I just cut it about 10mm higher than ground level for drainage to somehow prevent the sand from going in. Just had to wiggle the paver and tuff block a bit so I won’t block the drain. Luckily, we had some heavy rain before I put on the composite board and it was satisfying to see the rainwater draining properly.






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