raft foundation or mini pile foundation

[jaspercarrot]

which is the cheapest foundation for a new build house raft or mini pile foundation. the size of floor area is approx 40ft x 40ft i am doing all ground preparation myself any ball park figures for foundations please.

[buildersmate]

The cheapest sort of foundation is a strip foundation, then raft, then mini-pile.
Impossible to guess a price - how long is a piece of string?
It entirely depends on what type of soil you are on, the slope, the access arrangements and what you are doing to do with all the muck.

[jaspercarrot]

i am compacting all groud with hardcore etc ready for probably raft foundation firm to build raft on the hardcore base will be prepared to structual engineers spec. i just want to know the estimated cost of foundation.

[gordyagusta]

OPTION 1: Raft foundation for 40ft x 40ft x 200mm total concrete.... 30 cubic metres. ball park price �2800 inc vat.
OPTION 2 : Strip foundation for 160ft x 400mm x 400mm total concrete.... 8 cubic mtres. ball park price �750 inc vat.
OPTION 3 : Mini Pile foundation, not recommended. impossible to determine concrete volume until after piles have been drilled. but for a guide expect to pay around �85 / m exc vat.
You need concrete to the strength of either C35 for strip foundation or RC35 for raft foundation with steel mesh reinforcement and C35 with sulphate resisting properties depending on soil conditions for pile foundations, but i think you should be looking at the simple easy strip foundation unless otherwise specified.

Hope this helps

Gordon.