Watch our Adjustable Joist Support AJH38G (USA) Installation Video
The Adjustable Joist Support has been designed specifically to enable decks to easily be built over concrete slabs in areas where limited ground clearance is available. It is ideal for use when the step-down from your door to your concrete slab is between 4 inches (minimum) and around 10 inches (maximum)The AJH38G has been specifically designed to be used with 2 inch wide (metrically measured at 38 mm) pressure treated timber joists for USA markets.
The product comes in boxes containing 24 joist supports and 24 base plates.(see photo below) Bolts, nuts, washers etc. are purchased separately from your hardware store/merchant depending on what height you want to achieve.
Each Adjustable Joist Support ( joist holder + base plate) requires 2 x 3/8 inch Hex Head Bolts, 4 x 3/8 inch Nuts & 2 X 3/8 inch washers and 1 x 2 inch x 1/2 inch Galvanised screw anchor or similar.
How Packaged
Fully Assembled with Bolts,Nuts & Washers
Advantages of the Adjustable Joist Support
All joists should be pressure treated for outdoor use.
Joist Size | Recommended Span (feet) | Maximum Span (feet) |
2 x 4 inch | 3 ft 3 inch | 4 ft 11 inch |
*2 x 6 inch | 4 ft | 6 ft |
*Joist span limited by lateral loading on bolts
Note: All measurements based on using Galvanised long-threaded hex head bolts.
Hex Head Bolt Length | Min Height to Bottom of Joist | Max Height to Bottom of Joist | Min Height to Top of 4/6 inch Joist | Max Height to Top of 4/6 inch Joist |
2 1/2 inch | 5/8 inch | 1 inch | 4 1/4 / 6 1/4 inch | 4 1/2/ 6 1/2 inch |
5 inch | 3/4 inch* | 3 1/4 inch | 4 1/2*/ 6 1/2 inch | 6 1/2 / 8 1/2 inch |
**No Bolt | 1/4 inch | 3 3/4 / 5 3/4 inch |
* If using long bolts at low heights, to prevent the bolts protruding past the top of joist, the end of the bolt will need to be cut off.
** When Using Joist Support Only.