Cost of piling — is this fair?

[Marc1912]

Hi there

I'm having a small extension built (16m2). It has a piled foundation. The contractor originally estimated £7600 for the piles (8 piles, poured concrete, 6.5m deep, no particular complications, clay soil) he is now claiming he made a mistake in the estimate, and really it should have been £18,300, which is what he now wants to charge me! This is just for the piles, not the ground beams or anything else,

This seems bonkers to me, can someone give me a reality check?

Thank you

 

[noseall]

Hi there

I'm having a small extension built (16m2). It has a piled foundation. The contractor originally estimated £7600 for the piles (8 piles, poured concrete, 6.5m deep, no particular complications, clay soil) he is now claiming he made a mistake in the estimate, and really it should have been £18,300, which is what he now wants to charge me! This is just for the piles, not the ground beams or anything else,

This seems bonkers to me, can someone give me a reality check?

Thank you

Piling is a notoriously vague industry cost wise. I remember asking for a quote and being bamboozled by the risk-add-ons, which seemed to make the original quote meaningless. There were that many cop-outs due to ground conditions risk that you were in jeopardy of tripling the original quote, without even blinking.
Prices vary wildly from company to company, too.

 

[^woody^]

Should have got a fixed quote. Contractors can easily quote off the engineer's specification.

Get quotes now to compare. It is not reasonable that a competent contractor should be so far out with an estimate. Estimates are not guesses.

 

[Marc1912]

He is claiming that he made a mistake in the calculations, i.e. that he allowed for the wrong length of pile. It's all a nonsense (as it has been from the beginning with this contractor who I have now sacked, hence why he is acting like a $%@^@), but I would like to establish roughly if the final price quoted is at all 'reasonable' for the work done before going back to him ...

 

[johnny2007]

So, the work has already been done?
And he wants more than double what he originally estimated???
If so, pay him the £7600 and kick him out.
Give him your details and tell him to sue you.
I would really like to see him in court explaining his business model!

Imagine: He gives out reasonable estimates, work goes ahead, then, when everything is done and dusted, he realises he's made a mistake.
Who pays for his mistake?
The customer, of course.
Who else???

This grants my favourite punchline:

BOLL@X!!!

 

[jks7492]

Yep £18,000 is way over the top for 8 piles - thats over £2000 per pile!

 

[^woody^]

Any estimate should be within 10% of the actual cost. Increases would be for things like unknowns, additional (added on) works by others, unforeseeable work and suchlike.

A contractor making a mistake in his pricing is not reasonable, however a client may choose to contribute if the mistake is genuine and really did incur extra costs - ie its not right to penalise a contractor and get work for free.

 

[Marc1912]

Thanks JKS—and woody, in this case I don't believe it's a genuine mistake, he's trying it on.

 

[noseall]

Any estimate should be within 10% of the actual cost. Increases would be for things like unknowns...unforseeable

...like stuff underground for instance.. ?

 

[^woody^]

...like stuff underground for instance.. ?

The engineer would spec a foundation. The contractor prices from that spec. That is known work. That includes ground services survey.

A competent contractor would be able to give a fixed quote based on that specification either including for likely unknowns (higher quote as it includes more risk), else quote for the known work and estimate for the unknown work (provisional sums).

Then as work proceeds, the contractor adjusts the provisional sum once the unknown work becomes known.

That's how contracts run, not on estimates and guesswork.

Either way no contractor should carry out work above that quoted or estimated without the express approval of the client. Its not the contractors money, so he should not spend it without approval.

 

[Notch7]

Hi there

I'm having a small extension built (16m2). It has a piled foundation. The contractor originally estimated £7600 for the piles (8 piles, poured concrete, 6.5m deep, no particular complications, clay soil) he is now claiming he made a mistake in the estimate, and really it should have been £18,300, which is what he now wants to charge me! This is just for the piles, not the ground beams or anything else,

This seems bonkers to me, can someone give me a reality check?

Thank you

if the builder has done the work, then my guess is he has spent his cash flow and is trying to recoup some more.

If there are unexpected costs due to unforeseen circumstances -say a hidden well or something, then the builder should let the client know what the additional cost will be and get client approval before commencing


Its hard to know on cost, but a few years ago I got pricing for 8 driven piles -quotes varied from around £5k to £9k

My guess is £7,600 is around the correct price

I assume it didnt include the reinforcing steels, shuttering and casting of concrete skirt? -as that would add a few £k

 

[jeds]

Was the ground investigated before the quotes? Did the quotation specify a pile depth? The usual problem with piling is that people don't want to spend £2k+ on ground drilling to determine pile depth, so they rely on an estimated depth. That depth can end up being wildly different to the estimate. It's not uncommon for quotes to be based on a 3m pile. When work starts the machine pounds the piles into the ground until they reach a specified resistance. That might be 3m, 5m, 10m? Multiply that by 8 piles and a quote based on a 3m pile can end up being significantly more than the original quote.

To clarify, I am not defending a contractor that doesn't make this crystal clear. I've come across dozens of piling jobs where I have had to ask for clarification on behalf of a client because quotes weren't clear. The contractors simply reckon that if they quote for 3m piles and they end up being 10m then it is obvious that the client will pay for the extra depth.

 

[jks7492]

Cost will always vary depending on type/size/length of pile and the type of rig they can get onto site, but I’d say £600 - £1000 per pile is a decent ballpark figure.
Usually you’ll get a quote for the piling based on a specified pile depth, and somewhere on the quote (usually in small print) will be a standard rate per additional metre that each pile needs to be beyond the quoted depth.

As Jeds says, if you’ve not had a proper ground investigation done beforehand then the actual depth of the piles could be much deeper than the contractor assumed when quoting and the cost shoots up once they start work.

 

[Marc1912]

Thanks JKS

 

[noseall]

The engineer would spec a foundation. The contractor prices from that spec. That is known work. That includes ground services survey.

A competent contractor would be able to give a fixed quote based on that specification either including for likely unknowns (higher quote as it includes more risk), else quote for the known work and estimate for the unknown work (provisional sums).

Then as work proceeds, the contractor adjusts the provisional sum once the unknown work becomes known.

That's how contracts run, not on estimates and guesswork.

Either way no contractor should carry out work above that quoted or estimated without the express approval of the client. Its not the contractors money, so he should not spend it without approval.

Have you ever had a quote from Bullivants?
I have. And there are lots of caveats.
By the way, I have NEVER seen a ground conditions report accompanying a domestic extension drawings package, at the quoting stage.
EVER. It just does not happen.