blocks below ground level

I would have said it was against bulding regs to *use* thermalite below DPC.

Damn right.

Bloc/engineering brick up to DPC, then brick/cavty batts and thermalite above.

I was looking at a new housing site near me, and they were using what looked like lightweight 'Celcon' type blocks, about 300 mm wide, from below ground to DPC level. Then start cavity work, presumably. I assume, this is within current building regs., but surprises me a bit. Even without water ponding, cannot be good for these type of blocks to get damp. Mind you, on hol. in France, Vendee area on the coast, they were building house walls solely out of these blocks,

Look at the manufacturer's specs for whatever make of block you are using. Some type of aerated/lightweight blocks ARE classed as suitable for below ground. Phil.

Good. its nice to see common sense actually makes sense this time ! Cheers, Simon.

Thermolite 'trench blocks' or similar are suitable below DPC.

You can use concrete blocks, so long as they are solid IE, they don't have the hollowed out bit. concrete common bricks are the cheapest if you want to use these, engineers are a waste of money below ground as they far exceed the couple of newtons required

Most modern building are built on 300mm wide thermalite trench blocks - pretty much exactly the same as normal thermalite, but don't forget, they must stop at or below ground level and then a cavity wall is built up to DPC.

They are used solely for speed - building what might be 5ft high walls below ground is no fun at all using bricks.