Joist Support Frequently Asked Questions

 Download Graph "How to achieve joist heights using KlevaKlip Substructure Products"

 Download Min & Max Top of Joist height Information PDF

How can I purchase the KlevaKlip Adjustable Joist Support?

Via your preferred Timber Merchant or Hardware store or alternatively you can purchase on our Online Store

Where to purchase

How is the Product Purchased?

There are now two options  available when purchasing the Adjustable Joist Support- either the Adjustable Joist Kit which includes Bolts, Nuts, Washers and Dynabolts or the Adjustable Joist where they are not included.

Option 1: Adjustable Joist "Kit" (AJ45KIT): 

The product comes in boxes containing 16 joist supports,16 base plates, 32 x 100mm M10 hex bolts,64 x M10 hex nuts, 32 x M10 washers and 16 x 12mm dynabolts.

Option 2: Standard Adjustable Joist (AJH45G):

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 M10 Hex Head Bolts, 4 x M10 Nuts & 2 X M10 washers, 1 x 12mm x 50mm Galvanised 12mm dynabolt or x 10mm x 60mm masonry bolt or similar.

Differences between Adjustable Joist "Kit" (AJ45KIT)verses Standard Adjustable Joist Support (AJH45G)?


  • Easy sourcing – box contains everything you need to build your structure
  • Fully threaded 100mm length bolts provide maximum sustainability to cope with your required height and any irregularities in your concrete
  • Easy for the retailer – no special ordering or calculating of bolts etc, and no problems regarding thread length of stocked bolts 


  • All Kit bolts supplied are 100 mm length – sometimes customers require 120mm length bolts then purchase AJH45G
  • For top of joist height below 106mm, customers may need to cut off the portion of the bolt protruding above the joist (relevant for 70mm joists)

How is the AJ45KIT & AJH45G Adjustable Joist Support product packaged?

         AJ45KIT- How Packaged in box             AJH45G- How Packaged in box


         16 Base Plates & Joist Supports                             24 Base Plates & Joist Supports

     Includes: Bolts, Nuts,Washers & dynabolts Excludes: Bolts, Nuts,Washers & dynabolts or masonry bolts           




Which is the most economical way to purchase the Adjustable Joist Support – the AJH45G or the AK45KIT ?

All hardware stores sell their nuts and bolts at different prices, so we cannot be sure of what price you will pay. However the research that we have undertaken suggests that, as the nuts, bolts, anchors etc generally make up around 50% of the total costs, you are unlikely to come out “behind” by purchasing the AJ45KIT which includes all your nuts and bolts – unless of course you don’t need any nuts and bolts at all.

What are the Minimum and Maximum Top-of-Joist heights of the Adjustable joist support and Adjustable joist support "Kit"?

Minimum top of joist heights

76 mm – fixing joist bracket direct to concrete and using 70mm joist

86 mm – lowest height achievable using base-plate, 60mm bolts and joist bracket with 70mm joist

106 mm – lowest height achievable using base-plate,60mm bolts and joist bracket with 70mm joist

Maximum top of joist heights

150 mm – using Joist Support KIT 100mm bolts & 90mm joist

170 mm – using Adjustable Joist Support, 120mm bolts & 90mm joist

180 mm – using Joist Support KIT 100mm bolts & 120mm joist

200 mm – using Adjustable Joist Support, 120mm bolts & 90mm joist

200 mm – using Joist Support KIT 100mm bolts & 140mm joist

220 mm – using Adjustable Joist Support, 120mm bolts & 140mm joist

Note – the above information is a “practical” rather than an “absolute” document. There will be a number of ways to achieve the heights mentioned with different sized joists, however the installer should always be mindful to operate within the KlevaKlip product parameters and relevant joist span tables.

Can I use the Adjustable joist support with joists of greater than 90mm height?

Yes, the governing factor is 45mm in thickness, however there is no reason why the joists cannot be much greater than 90mm in height (eg, *120mm, *140mm ).

* When using 120mm or 140mm high joists 1200mm is the recommended and 1800mm is the maximum span for base plate positioning

Can I use the Adjustable joist support with hardwood joists?

Yes, provided they are only 45mm thick. However, please note that you will most likely need to screw into the joists rather than using connector nails (and maybe even need to pre-drill).

Can I use the Adjustable joist support with steel joists?

We have not yet found a steel joist of the right thickness, so haven't tested this as yet. There doesn't appear any reason why it shouldn't work.

Can I use the joist support cradle without the base-plate and just fix this to my concrete?

Yes, the joist support component is designed to be able to be used on its own in areas that warrant this. The ribs in the bottom of the joist support will still keep the joist off the concrete by approx 6mm /15/64 inch. You do of course lose the "adjustable" aspect of the product.

Can I purchase the joist support cradle separate from the base plates?

No, the products come as a pair in boxes and cannot be purchased separate from each other.

What are the minimum and maximum length Hex Head bolts can I use?

AJ45KIT : Comes with 100mm Fully threaded bolts- if you need to go higher purchase the AJH45G and 120mm M10 hex head bolts from your Merchant or Hardware store.

AJH45G : Minimum 60mm  Maximum 120mm galvanised Hex Head bolts.


Do I have to use the two washers for every adjustable joist support?

Yes, the washers are very important and form an integral part of the system.

What size galvanised dynabolt /masonry bolt or screw anchor should be used to hold down the base-plate?

AJH45G -1 x 12mm x 50mm Galvanised 12mm dynabolt or x 10mm x 50mm masonry bolt or similar. Note - if only using a 10mm dynabolt, you will need to use a washer under the nut to ensure you cover enough area of the base-plate.

What galvanising standards is the Adjustable joist support galvanised to ?

KlevaKlip Joist Supports and Base Plates have been hot dip galvanised in accordance with Australian Standards AS/NZS 4680:2006 (ISO 1461) 

What is the Load bearing capacity of the Klevaklip Adjustable Joist Support?

This has been independently tested to support a load bearing capacity of 350kg per square metre when used at the recommended joist spans listed below. Engineers and Load Test Reports can be found at the following link: https://klevaklip.com.au/Technical-Information

What are the box dimensions and weighs of the Standard Adjustable Joist Support and the Adjustable Joist Support "Kit"?

Standard Adjustable Joist Support Weight 6.5 kgs Dimensions Length 26cm x 19cm Width x 17cm Height

Adjustable Joist Support "Kit" Weight 8 kgs Dimensions Length 35cm x 18cm Width x 12cm Height

Can I install the Adjustable joist supports over brick pavers?

No, this is not recommended as the pavers do not have adequate structural stability.

How to calculate how many Adjustable Joist Supports are needed for your deck?

We quite often find that people have miscalculated the number of adjustable joist supports required for their decking area. We believe the main cause of this is that people work out the length of their joists, and simply divide by the "support spacings" (taken from our span table) they have decided on between the supports - eg - having a 3 metre length joist with spacings of 1 metre to give 3 supports. Wrong! - This does not take into account the initial support at the start of the joist.

Therefore, the correct answer would be 4.

Similarly, when working out the number of joists required, you need to work out the number of "joists spacings" along your deck and remember to add one for the initial joist.

So, to finalise the number of supports you will need for your deck, multiply the number of joists on your deck by the number of supports to be placed along your joists. This should give you an accurate answer.


How regular along my joists do I need to put the Adjustable joist supports?


See our span table below

Span requirements for base-plate positioning

All based upon "continuous span" with joists at 450mm between centre's

      Joist Size Recommended Span (mm) Maximum Span (mm)
70 x 45 MGP10 800 1200
90 x 45 MGP10 1000 1500
90 x 45 MGP12 1200 1600
*120x45MGP10 1200 1800
*140x45MGP10 1200 1800

*Joist span limited by lateral loading on bolts

Heights achieved when using 100mm for AJ45KIT, 60mm & 120mm long M10 Hex Head Bolts for AJH45G Adjustable Joist Supports (Aus/NZ)? 

Note: All measurements for 60mm &120mm are based on using Galvanised Zenith brand M10 hex head long-threaded bolts.

 Adjustable Joist Type Hex Head Bolt Length Min Height to Bottom of Joist Max Height to Bottom of Joist Min Height to Top of 70/90mm Joist Max Height to Top of 70/90/140mm Joist


Joist "Kit" (AJ45KIT)

100mm 16mm 20mm 86* / 106mm 130 / 150 / 200mm

Standard Adjustable Joist


 60mm  16mm  20mm 86 / 106mm  90 /110
120mm 18mm 80mm 88* / 108mm 150 /170/ 220mm
**No Bolt 6mm 76 / 96mm

* 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.

What are the dimensions of the KlevaKlip Adjustable Joist Support Base Plate & Support?