Decking Jacks Hardware

Adjustable Decking Jacks & Aluminium Decking Subframe System

Build and level a raised decking subframe with adjustable Deck Jacks, aluminium deck joists and compatible installation accessories. Glass House AU's Deck Jack system provides adjustable support for aluminium or timber joists, helping create a level subframe for composite or genuine timber decking.

Shop Deck Jacks in multiple height ranges, plus aluminium decking joists, extenders, packers, brackets and fixings for your decking subframe.

Adjustable Decking Jacks for Raised Decking

Deck Jacks are height-adjustable supports designed to make levelling a raised decking subframe faster and easier.

Made from polypropylene, the Deck Jacks are positioned on the substrate and support the joists above. Aluminium or timber joists can then be fixed to the Deck Jacks to create the subframe for composite or genuine timber decking.

Available Deck Jack sizes include:

• 20mm high

• 24–28mm

• 30–35mm

• 35–42mm

• 45–65mm

• 65–100mm

A 60mm Deck Jack spacer/extender is also available for compatible Deck Jacks when additional height is required. The extender is not compatible with the DJ-20 or DJ-24 models.

Aluminium Joists for Decking Subframes

The 55x40x3mm aluminium deck joist is manufactured from 6060 T6 aluminium alloy and supplied in 5500mm lengths with a satin black powder-coated finish.

These joists are designed to span across Deck Jacks, with the decking subsequently fixed to the aluminium joists. Composite decking or solid timber decking can be installed onto the joist system.

Joists are typically spaced at 450mm centres. Deck Jacks may be positioned up to 1200mm apart; contact Glass House AU for the relevant engineering information before relying on maximum spans for your project.

Direct-Fix Aluminium Deck Joists

For projects where an adjustable Deck Jack system is not required, the collection also includes an 80x40x3mm aluminium deck joist with an extended 25mm bottom flange.

Unlike the 55x40x3mm joist used with Deck Jacks, this profile is designed to be anchored directly to a concrete floor or other suitable substrate through the extended flange. Deck Jacks are not used with this joist.

Deck Jack Accessories & Levelling Components

Complete your decking subframe with compatible Deck Jack accessories, including:

• 60mm Deck Jack spacer/extenders for compatible Deck Jacks

• 3mm Deck Jack packers for final height adjustments

• 1mm and 3mm horseshoe packers for levelling adjustments

• 50x50x3mm aluminium angle brackets

• Stainless steel 304 self-drilling screws for fixing aluminium joists through the Deck Jack support brackets

Check the individual product information before ordering to confirm the correct component and compatibility for your installation.

Decking Jacks FAQs

What are decking jacks?

Decking jacks are supports positioned beneath decking joists to create and level a raised decking subframe. Glass House AU Deck Jacks are height adjustable and can support aluminium or timber joists for composite or genuine timber decking.

What heights are the Deck Jacks available in?

Deck Jacks are available in 20mm fixed-height and adjustable models covering 24–28mm, 30–35mm, 35–42mm, 45–65mm and 65–100mm.

Can I increase the height of a Deck Jack?

Yes. A 60mm spacer/extender is available for compatible Deck Jacks. Up to two extenders can be used to add up to 120mm. Extenders cannot be used with the DJ-20 or DJ-24 Deck Jacks.

Can Deck Jacks be used with aluminium joists?

Yes. The 55x40x3mm aluminium decking joist in this collection is designed to span across Deck Jacks. The joist can then support compatible composite or solid timber decking.

Can Deck Jacks be used with timber joists?

Yes. The Deck Jack system can be used with aluminium or timber joists. Appropriate fixings should be selected for the joist material.

How far apart should Deck Jacks be installed?

The product information recommends joists at typically 450mm centres and states that spans between Deck Jacks can be up to 1200mm. Contact Glass House AU for engineering information relevant to the Deck Jack spans before installation.

Do Deck Jacks need to be screwed or glued to the substrate?

The Deck Jacks are designed to be placed onto the substrate without being screwed down or glued. Installation requirements for the complete deck should still be assessed for the specific project.

Can I use the 80x40x3mm extended-flange aluminium joist with Deck Jacks?

No. The 80x40x3mm aluminium joist with extended bottom flange is designed to anchor directly to a concrete floor or other suitable substrate. Deck Jacks are not used with this profile.

What decking can be installed over the Deck Jack system?

The Deck Jack and joist system is suitable for creating a subframe for composite decking or genuine timber decking. Check the decking manufacturer's installation requirements before fixing the decking to the subframe.

Shop Decking Jacks & Aluminium Decking Subframe Components

Choose your required Deck Jack height and add the appropriate aluminium joists, extenders, packers, brackets and fixings for your decking project. Check each product listing for specifications and compatibility before ordering.