The Construction Centre
Magnifying Glass

Thermalite Block Companies in the UK

  • Forterra are a UK supplier of heavy building materials with a product range comprising of clay bricks, Thermalite blocks, aggregate blocks, Red Bank chimney,...


Where to buy thermalite blocks

  • Forterra - 5 Grange Park Court, Roman Way, Northampton, Northamptonshire, NN4 5EA, 01604 707600

Can I use 100mm thermalite blocks on an external house wall that will be rendered?

Also, what mix should I use?

Yes, you can use sand and cement render on Thermalite.

However, you don’t say in your question which Thermalite block you are intending to use.

The properties of each block varies. For example 480kg/sq.m for the density of

the Turbo block; 550kg/sq.m for Shield and 760 kg/sq.m for Hi-Strength 7.

The latter two also have higher moisture resistance which is important if you are

to render the outer leaf of the cavity wall. Similarly, you don’t describe the full wall construction; cavity width, insulation, inner leaf etc.

As to render mix, the composition must be compatible with the background upon which it is to be

applied. Aerated concrete blocks also shrink so you need to make sure joints are provided to

accommodate the movement.

I advise you get some professional advice to ensure you get it right – Try Hanson as their technical guys are very helpful!

Leigh Tugwood - Architect -


Can I use thermalite blocks to build a 7m x 4m shed 2.4m high single skin with a timber internal frame. If so, what type I will render and clad the external walls.

The most suitable type of render to use is largely dependent on the thermalite block you have chosen. It is best to seek professional advice from the technical team at the manufacturers, Hanson. Tel:08705 626500

Kind regards

Debbie Prince - The Construction Centre

What is the NT strength of thermalite turbo block

What is the U or the R value of the turbo block.

Also for the Hi-strength 7 block.

We are building a new house, with the roof space turned into a loft room. Do you count this as a two or three story ?. What block do you suggest we use ?.

R J Gore and Son.

It may be best to direct your questions and discuss your requirements with the manufacturers Hanson ,as the 'U' and 'R' values are dependent on how the blocks are used e.g partially filled cavity wall, fully filled cavity or solid wall with render. The definition of 3 storey also varies so it may be best to check with Hanson e-mail or your local building control team (contact details can be found above under 'Construction Resources').

Kind regards,

Debbie Prince - The Construction Centre