Quote for Raft Foundation

[CJW1968]

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?

[welsh brickie]

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

[CJW1968]

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?

[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.

[welsh brickie]

[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