Thermalite shield blocks= wickes airated 3.6N blocks???

[Iza]

Hi
I'm new on diynot but have been visiting this forum for over a year.
I wonder whether someone could help.
We gonna build a rear single storey extension this summer.
I was just looking at wickes website and they have special offer on their light weight blocks 3.6 N. Prison who works there said they not suitable for extension as they not strong enough and advices 7N once.
We will have cavity wall inner and outer leaf out of block with render on the outside.
Architect said thermalite shield block.
What is the difference? Is there any apart from the price?

Would be grateful for any help...

 

[RonnyRaygun]

3.6N blocks will be plenty strong enough for a single storey extension.

There is little difference between different manufacturers' blocks, possibly a nominal lower or higher λ value.

 

[Iza]

Thank you for that.