Need framing suggestion for low level deck

[nvelaga]

Hello experts, 

I am looking to do decking project (3.8m *5.7m ) to transform my back yard. The deck runs across concrete and the soil and the major portion lies on concrete. Attached is the plan of it. 

Height difference between the concrete slab and the bricks under exist door is 60mm. How to achieve framing (driinage , strength etc ) in this low clearance situation ? 

[nvelaga]

Thanks @MitchellMc , 

1. How many of such pedestals needed for 1m of timber ? 

2. I am thinking to use https://www.bunnings.com.au/70-x-45mm-outdoor-framing-h3-treated-pine-5-4m_p8032136 for joists and bearers ? Does this sufficient or do we need to go for h2 level considering the clearance is less ?

[MitchellMc]

Since you're laying the joists on their face @nvelaga, which already is not something that is recommended, you would have to at least go for the 90 x 45mm and not the 70x45mm. H3 is the minimum grade acceptable for exterior use. H2 is for internal use.

For a 90 x 45mm joist on their edge, you'd support them every metre. However, since you are laying them on their face, which significantly reduces their span capabilities, I'd recommend having support at least every 800mm at a minimum.

Mitchell

[nvelaga]

Understood , thanks @MitchellMc. Just to confirm bearers in all directions will also need to lay on their face  right ?

[MitchellMc]

If you're working within the height you've specified, them laying on their face would be the only option @nvelaga. If your working height increases sufficiently once you're off the concrete, you could consider switching their orientation.

Mitchell