cost difference between piles and strip foundation

[paulgh]

Hi all,
i'm doing an extension - 2 storey side and rear - and have been told may need piling as we are close to an existing mature tree (c.2m) and have had a very large mature tree removed due to bleeding canker on the line of the new footings.
we've had rough costs provided based on standard foundations and i was hoping to get a rule of thumb idea of the extra cost for piling.
assuming the previous plan was 1.5m strip and the total length of foundations will be 20 metres, any ideas on the cost of this?
thanks in advance for any help with this.

 

[limerockconstruction]

It's difficult to say without knowing more...but in fairness a local piling firm could price it up in an afternoon for you. It depends on the ground conditions? type of pile? Beam or raft? Clay heave or not? Amount of excavation required....I'm afraid it's a bit tricky to guess.

Just to let you know I'm on a job at the moment and my original price was 9k for groundworks and since the tree people made us pile these parts of the works have gone up to 19k

 

[jeds]

As above. Local piling firms get to know local ground conditions and might be able to give you a guide, but even they won't know how deep they will need to go without a test bore. A test bore can cost £1500 to £2000. The other option is they give you a base cost for a certain depth but you have to accept that the cost will increase if they find they are going deeper than expected.

 

[paulgh]

ouch, fingers crossed we can get away without but i suspect not.
Many thanks for the input and apologies for delay in getting back, thought i ticked the box to be notified about responses.