Backfilling/filling cavity

[23vc]

Hi
Would anyone be able to check my logic for the next steps of getting my extension out of the ground? The foundations are now poured to 450mm below damp.
- I was planning on laying one course of blocks (to get within 225mm of dpc) then filling the cavity with lean mix concrete then running the trowel along it to slope it towards the outer skin? Then laying the rest up to dpc.
- back filling after getting to dpc I was planning on using a mix of soil and hardcore, but have heard that you shouldn't use soil, any opinions appreciated!

 

[noseall]

No fertile matter! Clean sulphate free hard core only.

Your cavity fill method is sound.

 

[garyo]

What about foundation clay? Okay?

 

[23vc]

Thanks noseall
Although bco has since ok'd just using soil ?! (Gary)
Think I'll look into the risks here a bit more - any views welcome

 

[garyo]

I've used clay a few times... I thought it was the norm.

 

[noseall]

Are we talking back filling inside or outside the building foot print?

 

[garyo]

Ah - I was talking about the outside. I treat the inside to be an extension of the hardcore/slab compaction etc.