Air-Crete blocks as a standard give you a better U-value than a concrete block, but if you can use an alternative or get your architect to change the specification, we can supply the following instead:

  1. 100mm Medium dense block as a first choice (better in U-Value)


  1. 100mm Dense block as a second (cheaper in price)


To make up the U-Values, there are two options available:

  1. Upgrade cavity insulation for example use Dritherm 32 instead of Dritherm 37 (the lower the U-Value the better the performance) and/or upgrade the thickness 100mm to 125mm or even 150mm depending on U-Value required.
  2. If we need an even lower U-Value still we can supply insulated plasterboard.


If the U-Values need to be even better, then we can source the Kingspan K106 cavity insulation which achieves some of the lowest U-Values on the market when mixed with a K118 insulated plasterboard.

If your drawings tell you the exact U-Value as a minimum that you will need to achieve, you can use the following U-Value Calculators to work out the build-up and result:


Kingspan = Calculator (  


Knauf = U-Value Insulation Calculator Free Online | Knauf Insulation


To be able use the alternative option, you will need to do the following:

  • Check with your architect and/or building control to ensure conformity and achieving correct U-Values
  • Ensure the footings are big enough and can take additional weight as the blocks weigh quite a bit more (see below).



Dense = 18.7kg each or 217kg per m2

Med-Dense = 12.8kg or 128kg per m2



Shield = 5.8Kg each or 88kg per m2

Hi-7 = 7.1kg each or 101kg per m2

(M2 above include mortar weight at standard 3kg per block)


Also, have you been struggling to find a 215mm block? We can supply our standard 100mm blocks as they are 215mm high. 

If you lay them flat on the side it will achieve the same end effect (please bear in mind this uses double the quantity, so please allow 20 blocks per m2).


Contact our Mitcham Branch Manager, Drew Seville, for more information.

Contact Drew
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