# Forum Home Renovation Structural Renovation  H1 v H2 soil footings cost difference

## tombsc

Hi all
My engineer has designed footings based in H1 soil, but my soil test states H2. I asked him to update the footings spec, and he came back with this: 
"Strip footing is designed for Class H1 site. 
The soil test has a Class H2, which means deeper footings are required. 
However, for extensions, footings can be the same depth of existing, providing the existing has performed OK for over 10 years. 
Suggest the owner expose the existing footings at the proposed extension junction, and advise us of existing footing depth. (use photo/tape measure). 
Alternatively, deeper footings can be specified, which would be more expensive, and probably unnecessary." 
I don't really have time to dig a big hole at the moment as I'd need to remove some thick concrete which totally surrounds the house and I have a million other things that I need to do. I need the footings specs finalised asap so I can get my building permit approved. My question is, if I decide to just go with the deeper footings for H2 soil, what kind of additional cost would there be? Am I looking at hundreds more, thousands more? 
Thanks   
The extension is Bed 4, the two ensuites and the deck           
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## tombsc

:Frown:   
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## intertd6

Are you the builder or owner? Somebody should have found out the depth of the original footings so the new footings can be at least the same dimensions,  if the engineer does it then he's going to charge appropriately, If was doing this project I wouldn't  leave myself open for footing movement later on down the track, even if the engineers design was deficient caused a fault the first one to be defending a claim is the builder.
regards inter

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## tombsc

Thanks inter. I'm the owner (owner builder). 
I'm leaning towards your view that we should have the footings needed for the soil. But if this is going to cost me $2k more I'll need to put more thought into it. Any idea on what the cost difference would be?
Thansk  
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## Marc

Two questions, is it necessary and if so how much more... 
A hard ask for someone to just venture a figure for additional cost of footing for a project that size. Clearly you must ask your concreter that question.  
As far as the need or not for such upgrade, your engineer told you to dig a hole and check your existing. If you can not do that, you have two choices. 
Pay the additional whatever it is, 
or take the risk.
I would say that digging a couple of holes in two or perhaps 3 different places to ascertain the existing footings depth is way cheaper. 
May be pay someone to dig? Still much cheaper.
Call for a concrete X ray service?

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## Bertoluci

I agree with Marc. A sensible suggestion. Also have a look at the National Construction Code/BCA Vol2 page 151Fig 3.2.5.4(b). Ignore this if you have already done so. My recommendation, go with Marc's advice. Good luck tombsc.

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## Bertoluci

Woops should have looked at date. New to this!!

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## tombsc

Thanks Marc. I hadn't even thought about paying someone to dig the holes for me - doh!
I'll post a job in Hipages and see if I can get it done this week when I'm at work.   
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## tombsc

Hmm. There's an old patio under my patio lol    
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