DIY Doctor UK DIY Forums

My builder has started a single story extension - 6m x 3.5m and we've hit a snag in that building control will not approve the original architect's depth for these of 1.2m and have advised to dig down to 2.6m due to a neighbouring tree.

My builder is telling me that he cannot dig down to 2.6m - due to lack of access for a larger digger - and that the building of raft foundation on the existing depth would be an acceptable solution. However, he tells me that this will cost £6,000 plus VAT on top of the original quoted cost - which equates to an extra 25% of the entire cost of the project.

Can anyone please advise as to whether these extra costs are reasonable?

that sounds reasonable, he has to have plans drawn with structural calculations,excavation costs, rebar,
and the concrete which isnt cheap.

But the excavation costs have already been accounted for in the original 1.2m quote?
He doesn't had to dig any deeper? Nor order any more concrete?

Thanks for your reply but there aren't any more excavation costs or concrete - as they were part of the original quote! So is £6,000 plus VAT reasonable for the buy and fitting of the bars for this raft foundation? How much should it cost?

Be grateful if someone could advise.

Many thanks.

[quote="CJW1968"]Thanks for your reply but there aren't any more excavation costs or concrete - as they were part of the original quote! So is £6,000 plus VAT reasonable for the buy and fitting of the bars for this raft foundation? How much should it cost?

Be grateful if someone could advise.

Many thanks.[/quote] the origonal quote was for a strip foundation,In my understanding of your discribtion.With a raft foundation the whole square meterage has to be excavated to the depth of 1.2metres