I built a 90 x 19mm Merbau deck over a concrete slab and pavement in my alfresco area. The maximum height I was able to build the deck was 9.5cm as I could not cover the weep hole in the wall. The main issue I had was building over the concrete pavement since it had a 70cm slope over 1m. I used 70 x 45mm treated Pine for the joists in the slab area and 90 x 45mm and 140 x 45mm treated Pine in the pavement area.
An issue to overcome was the brick pillar supporting the roof as I needed a way to nail the decking against the post. I overcame this by creating a frame that surrounded it. The decking then had an easy attachment point. To give a pleasant finishing touch, while concealing the ends of the decking boards, I created a picture frame to enclose the entire deck.
Before and after
How to build a low-level deck
A low-level deck can pose a range of potential design and installation problems, with particular challenges around ventilation, drainage, termites and rotting. But it doesn't have to be a difficult project once you take the time to understand the basics of how they are put together.