Piling - how much????

[Terry77]

Hi,

Just got our engineers report back!!! so now were over £2000 down the road with architect, soil test and engineers report we find we need piling. 4000 x 4000 single storey extension flat roof three walls, 1 x window and double French doors. On clay but not a flood plain, no cracks in existing bricks or mortar. Our house isn't piled nor any neighbours nor the neighbours extension so why does our extension need piles?

Have regulations tightened up that much?

Are engineers covering their back sides these days?

The calculations have been sent to building control so is this final?

Is there a cheaper way?

Big question is how much does it cost to pile?

we were quoted £2,800 for standard footings, moving soil from site, inc digger hire. We now need 4 piles not sure how deep but I understand they are priced per metre.

thanks in advance of any answers.

Kind Regards

Terry

 

[ban-all-sheds]

This is not a question about the forum, is it.

So you should not have posted it in the New Forum Help section, should you.

 

[Terry77]

Sorry only just joined this forum. just followed the button when it said post thread. I'm guessing from your reply I've done this wrong? ps are you yoda?

 

[^woody^]

Why did you need an engineers report in the first place. Does that answer your question on the need for piles?

Don't forget to add the price of pile caps, floor, and engineers design costs for these to your £8k.

 

[Terry77]

Advised by the architect to use him. I emailed him yesterday and explained how shocked we were the only people around that had needed an extension piled he has now said he will look at more affordable ways of achieving the footings. It sounds to me like a lot of engineers don't bother working out cheapest against safest and correct footing for the build but just cover themselves by going overboard and then charge through the nose for it.

 

[stuart45]

It can depend on what type of clay you have and whether there are trees nearby.

 

[Terry77]

We did have a eucalyptus tree about 5metres tall within 3 metres of the build but that has since gone.

 

[stuart45]

Have a look at the NHBC foundation calculator. What was the result of the soil test. High, medium or low?

 

[RonnyRaygun]

We did have a eucalyptus tree about 5metres tall within 3 metres of the build but that has since gone.

The tree still needs to be taken into account, but at 5m high you can take the height at removal and ignore the mature height for foundation depth purposes.
Even if you've got high volume change soil the foundation will not need to be any deeper than 2.5m locally, stepping down as you move further from the tree.

 

[Terry77]

looking at the soil report it says London clay. is that good or bad news?

 

[jeds]

looking at the soil report it says London clay. is that good or bad news?

The key question is the soil volume change potential of the clay? In your case, with a Eucalyptus 3m away, it makes a difference of a 1m deep foundation for low change to nearly 2.5m deep for high change. But either way both scenarios could be covered by a strip foundation. How long ago was the tree removed and, what specific reason does the engineer give for specifying piles?