Foundation Blocks vs Dense Concrete Blocks

[zappastix]

Hi

The structural engineer has stipulated that concrete blocks have got to be built up to ground level (around 1 metre).

In fact two concrete blocks, side by side (so that brick & block courses can continue).

The cavity for the concrete blocks has got to be filled with lean concrete.

Just trying to price everything up and I came across "Foundation Blocks" at Wickes.

The size is different 44 x 21.5 x 30cm (Foundation Block), as opposed to Dense Concrete Blocks 44 x 21.5 x 10cm

Couple of questions;

Is there any benefit to using Foundation Blocks?

As the structural engineer did not mention Foundation Blocks, should I just use Dense Concrete Blocks?

Just a bit more info;

Whatever blocks I use, they are to be built off a slab / 3.5 cubic metres of C20 that was laid last October around 225mm thick.

As you will see from the image, the water table is high and because there is no soil the slab just holds the rain, so whatever I use
I don't want the blocks to deteriorate overtime.

Do they deteriorate overtime?

Any help, reassurance would be most welcome.

Thanks

Stephen

Untitled

• zappastix
• 16 May 2012
• 2

Untitled

• zappastix
• 16 May 2012
• 2

 

[stuart45]

Foundation blocks are quicker, but cost more for materials.

 

[^woody^]

You can use foundation blocks no problem. Just make sure you stop them at least 225mm below external ground and then use brickwork - this is for frost cover.

They are easier to build with in a trench than two skins of other blocks, and you don't need to mess about filling cavities