Hi,

 

I am getting ready to have the foundation laid, and whilst studying the engineering plans there is no reference to which particular block to use, other than 7N strength.

 

I am particularly fond of Thermalite due to their weight, and superior uValue vs concrete block.

 

Forterra (the Jetfloor supplier) provide a standard detail using their 300mm thermalite block. We are building a TF, so 140mm in our case.

 

The product I would use is the one here:

 

https://www.forterra.co.uk/product/thermalite-aircrete-hi-strength-7/

 

Structural / foundation designer detail is as follows:

 

 

 

Any pros and cons pls?

 

Thanks

Bart

 

 

I would rather use a block of your finest cheddar than a thermalite, solid concrete block all day long for me. 

don't know how much the Thermalite blocks are but would've thought a lot more than solid concrete blocks. so save the money and use solid concrete and put the money towards more insulation on the floor.

It's outside of insulation envelope, having the best insulator thee will do nothing (or close to nothing).

Instead I'd think hard how to replace the kickerblock to avoid cold bridge there (and still be able to mount TF well)

Thanks for the replies.

 

There is a quick and easy fix to thermal bridge created by the kicker block, and that is Marmox. It works out bonkers expensive at the quantity we would need, and I simply am unable to go for that.

 

But very useful insights regarding the trench blocks. Thanks!
 

I'm not sure if Thermoblock would be ok for mounting TF to, but moot point if out of budget. Second best option to mitigate bridging would be perimeter insulation using phenolic.