How to build ground level deck?

biggysi

I'm planning to build a deck using ekodeck system, 5060mm×4000mm with joists spanning 4000mm, i have a slab over verandah that span only 1200mm and the rest of the back yard is dirt, the slab steps down only 90mm from the house so I'm planning to use 70×45 H3 for the subframe, I'm not sure what the requirement is to support the joists spanning this long, I'm looking to use the plastic pedestal feet mini size as minimum depth is only 25mm, i need advise on the spacing of pedestal for each joists?, and also on the concrete section will i need to bolt the subframe to the slab or they can just sit on the pedestal pods?

Over the dirt area the soil is compacted but unlevel so the plan is to use pedestal pods to level out the subframe and sit them on the ground directly or do i need to to dig and pour concrete and use posts to connect the joists to a beam at the end of 4000mm? And use the pedestal only half-way?

MitchellMc

Welcome to the Bunnings Workshop community @biggysi. It's fantastic to have you join us, and many thanks for your question about constructing a deck.

You might like to read through this helpful guide: How to build a low-level deck.

Ideally, your joists should be at least 90×45 mm for strength and minimal deflection. Using 70×45 mm is really on the light side and will need closer support. Over soil, the ground must be well compacted, and you should place a solid footing under every pedestal, like a 300×300 mm paver to spread the load, since the mini pedestal feet have a very small footprint.

Over the concrete slab, the joists can generally sit directly on the pedestals without bolting down, provided the slab is level and solid. For spacing the pedestals: with 70×45 mm joists at 450 mm centres, place pedestals roughly every 700 mm along the joist. If you were using 90×45 mm joists, spacing could be a bit wider, around 750 mm.

Over the dirt section, the pedestals can be used, but make sure the ground is compacted, level and that they are on a paver. An alternative would be the TuffBlock 300 x 300 x 90mm Instant Foundation System Deck Support, which can sit directly on compacted ground.

Please let me know if you have any questions.

Mitchell