Starting digging our single story extension on Monday and that means ordering concrete. I need to dig down 1m deep, and to tie in with the current house I figured I'd finish concrete 1 brick below ground. Which means I'll have 3 bricks in total up to DPC (1 below ground, 2 above).
But my digger driver said it might be worth using trench blocks to save a little on concrete.
I worked it out as D: 450mm * W: 600mm * L: 18m, which works out to 3 cubic metres, or 432 GBP.
Alternatively I can lay 41 of these Toplite Aerated blocks of L: 440 * W: 300 * H: 215, which would cost me 180 GBP.
That's a saving of nearly 252 GBP, which might be worth the extra work. I might even consider two rows of these blocks to save a little more, but won't go further to save my back.
Is there any reason not to use these? I assume Building Control would be equally happy with me filling my trench with:
But my digger driver said it might be worth using trench blocks to save a little on concrete.
I worked it out as D: 450mm * W: 600mm * L: 18m, which works out to 3 cubic metres, or 432 GBP.
Alternatively I can lay 41 of these Toplite Aerated blocks of L: 440 * W: 300 * H: 215, which would cost me 180 GBP.
That's a saving of nearly 252 GBP, which might be worth the extra work. I might even consider two rows of these blocks to save a little more, but won't go further to save my back.
Is there any reason not to use these? I assume Building Control would be equally happy with me filling my trench with:
- 925mm of concrete + 65mm brick & 10mm mortar joint to make up the 1m to ground level, or
- 710mm of concrete + 215 trench block & 10mm mortar joint + 65mm brick & 10mm mortar joint
- 485mm of concrete + 2 * (215 trench block & 10mm mortar joint) + 65mm brick & 10mm mortar joint
