After getting some good advice from EricL and Adam_W in this discussion, we made a start on our low-level Ekodeck project. The advice I got from this forum and also from Ekodeck directly has been invaluable.
For the substructure we decided to use heavy-duty angle brackets for the bearers and used a combination of blue-tip screw bolts and DynaBolts to secure the brackets to the concrete. We used the screw bolts for all the brackets close to the edges of the concrete and DynaBolts everywhere else.
We used plastic shims to help with lifting and levelling the substructure and joist tape to help give the timber added protection and hopefully greater longevity.
We did end up modifying our design a little (moving the breaker boards) just to make better use of the Ekodeck boards and to minimise using really small pieces around the bay window.
As our concrete wasn’t a perfect rectangle and the levels weren’t even (the concrete was slightly higher near the expansion joints) there were definitely some challenging moments. And working in varying temperatures meant we had to be mindful of the expansion and contraction capacity of the Ekodeck product.
The first thing we did was complete the perimeter of the substructure. We then attached the joists – for most of the joists we used joist hangers, but some of the angled pieces we just screwed together. We also had to work around the pergola posts and downpipe.
Once the framework was complete we started working on lifting it to achieve the desired level.
We first placed the angle brackets in the desired location – aiming for approximately 800mm spacing (as we used the 75mm x 45mm H3 treated Pine) and alternating sides where we could. On the perimeter pieces we had to put the angle brackets on the inside, and sometimes where the joist was very close to or over an expansion joint in the concrete we had to put the angle bracket on the other side of the joist.
We attached the angle brackets to the concrete using DynaBolts or connector screws and then packed under the framework to get the desired lift. Once in place we attached the framework to the angle brackets.
As the concrete was sloping away from the house we had to be mindful of lifting it the right amount in the right place. We also siliconed the packers in places just to prevent them from moving over time.
Once everything was in place we added the joist tape.
The first step in laying the deck was to do the picture framing and edge boards. We had to mark and cut around the posts and pipes while allowing for expansion and contraction of the decking.
Once the edging was done we could start laying the deck in sections.
How to build a low-level deck
A low-level deck can pose a range of potential design and installation problems, with challenges around ventilation, drainage, termites and rot. But it doesn't have to be a difficult project once you take the time to understand the basics of how a low-level deck is put together.