Futurewood’s specially designed aluminium joist and low-height adjustable pedestal subframe system allow for an easy installation of a low-maintenance, CleverDeck composite timber deck over a rooftop membrane or a concrete patio, balcony, or alfresco area.
The low-height subfloor system is designed to be used in situations where there is a limited amount of height between the proposed deck surface and external door openings, or where there is a waterproof membrane that cannot be penetrated with fixings, such as on a rooftop or balcony.
The low-height subfloor system consists of:
- 25mm x 50mm black aluminium joists
- Stainless steel, right-angle and adjustable angle brackets, and joiners (for aluminium joists)
- A range of adjustable height pedestals from 18mm to 140mm in height and Double Joist top plates
Additional aluminium joists/bearers and an expanded range of pedestals will be added to the aluminium subframe range in early 2024.
This system requires a solid, stable, well drained surface for the subframe to sit on. Ideally, the surface would be a concrete slab, pavers, or tiles. If the subframe is installed over a garden or lawn area, the area must be well drained. Any vegetation needs to be removed along with loose soil until a solid, stable clay base is established, a geo-membrane should be applied over the bare soil with 300mm x 300mm x 50mm concrete pavers placed on the ground at appropriate intervals to support the pedestals.
Using a combination of the adjustable pedestals and the aluminium joists, the low-height subframe can be set from 43mm to 165mm in height, meaning that when a 23mm thick decking board is added, the minimum clearance height becomes 66mm and covers a range up to and including 188mm*.
*This does not allow for any adjustments that may need to be made for uneven or sloping ground.
The 25mm x 50mm aluminium joists and adjustable pedestal sub-frame have been designed and tested for a safe working load of 2KN/m2 (uniformly distributed load), or an applied load located anywhere on the span of the joist of 1.8 KN when supported at 450mm centres.
When an overall deck height is greater than 188mm, the 25mm-thick aluminium joist can be replaced with larger 50mm or 90mm aluminium joists. The larger joists provide greater spans using a joist or a joist/bearer combination up to 1800mm and combined with pedestal heights up to 320mm, provide a total deck height of 483mm. Higher deck heights can be achieved by substituting the adjustable height pedestals with concrete stumps.
For further information on Futurewood’s low-height subfloor system visit futurewood.com.au/aluminium-joist