Breeze blocks

Usually, but check the specific product for suitability. Celcon Foundation or similar is recommended for this application, but many standard blocks should also suffice. However, a wide block like the Celcon Foundation seriously reduces the amount of labour required, as you can lay the entire thickness of foundation in a single course and only split into cavities above the DPC level.

Yes.

Yes.

Christian.

I always thought you had to use engineering bricks in foundations (I'm not disputing what you say, just never heard of Celcon Foundation!)

David

Nah. Most concrete blocks (including aerated) can be used in most soils, at least according to the manufacturers. But you should check the particular combination of soil and block.

Christian.

P.S. For further recommendations, use Celcon Standard in the outer leaf and Celcon Solar in the inner leaf. However, you'll probably just end up at the builder's merchants where they haven't heard of anything except bog standard

Christian.

Yes, I thought the reply was - a bit misleading, like saying 'you can use brick for a fioundation' without saying 'but most people pouitr concrete and use really exepensive ones up to the DPC, for good reasons.

Strange, as the thermal blocks used for internal walls will expand when they get wet and contract again when they dry out, which sounds like it would be really bad news in foundations below the damp proof course. (You have to be careful plastering them for this reason.)

That's why you use special underground non thermal concrete blocks.

I have to say that I did not consider celcon thermal blocks to BE concrete actually.

Clearly, the manufacturer disagress, though!

Cheers, Chriatian

Jon