Your browser isn't supported
It looks like you're using an old web browser. To get the most out of the site and to ensure guides display correctly, we suggest upgrading your browser now. Download the latest:

Welcome to the MSE Forums

We're home to a fantastic community of MoneySavers but anyone can post. Please exercise caution & report spam, illegal, offensive or libellous posts/messages: click "report" or email forumteam@. Skimlinks & other affiliated links are turned on

Search
  • FIRST POST
    • Kate0408
    • By Kate0408 18th Apr 17, 1:08 PM
    • 15Posts
    • 1Thanks
    Kate0408
    Soil investigation/borehole for new ground floor extension - advice needed!
    • #1
    • 18th Apr 17, 1:08 PM
    Soil investigation/borehole for new ground floor extension - advice needed! 18th Apr 17 at 1:08 PM
    Good afternoon,

    We are in the process of getting plans together for a proposed ground floor extension to our home.

    We currently have a garage with a utility room behind the garage, joined into the side of our house.

    We are looking to rebuild the above, bringing the garage further forward and creating a downstairs bedroom.

    We have spoken to a structural engineer, who has agreed to design the foundations etc, but he says we need to get one borehole dug to check the soil type, before he can decide on which foundations will be required.

    We have a fairly limited budget for the whole project and we are uncertain if our engineer is being overly cautious. We don't want to throw money away if we can avoid it.

    Do we really need to get this done? Can't we just dig a test pit to check?

    The cost for boreholes look to be very expensive (£1k upwards).

    We previously had planning passed (inc building regs) for a double height extension and the planning approval did mention the following:

    "The applicant is advised that the site to which this planning permission relates is recorded by The Local Borough Council as being on or in the vicinity of land of potentially contaminative use, that was a works and gravel pit.

    Prior to the commencement of the permitted development, the applicant is advised to undertake a suitable and sufficient site investigation and any necessary risk assessment to ensure the land is free from significant levels of contamination."

    Our previous architect said that we did not to do anything about the above, unless we found anything once the build commenced.

    The road we live on is full of 1960's built homes along with much older houses. There is an old gravel pit which is being redeveloped at present on the very edge of our riverside village, but there is nothing to make me think there would be a problem with the soil where we are!

    Any advice or information would be much appreciated.

    TIA







    Sent from my iPhone
Page 1
    • the_r_sole
    • By the_r_sole 18th Apr 17, 2:01 PM
    • 2,271 Posts
    • 1,133 Thanks
    the_r_sole
    • #2
    • 18th Apr 17, 2:01 PM
    • #2
    • 18th Apr 17, 2:01 PM
    You have a suspensvie condition requiring that a site investigation and associated risk assessment are carried out "Prior to commencement" i.e. before you start, so not sure how that would mean you don't have to do anything about it until after you start? Normally you write to the Local authority and get them to confirm that all conditions have been satisfied to allow you to start work.
    I don't understand how you managed to get building regs passed without an engineer confirming the suitability and design of foundations?
    What is his reasoning for asking for a borehole? perhaps the ground conditions would mean that this is most suitable way to assess the ground for construction? Or is the borehole for the Site investigation in regards to contamination etc?
    • Kate0408
    • By Kate0408 18th Apr 17, 2:13 PM
    • 15 Posts
    • 1 Thanks
    Kate0408
    • #3
    • 18th Apr 17, 2:13 PM
    • #3
    • 18th Apr 17, 2:13 PM
    This is the whole section in full (taken from planning approval).

    4. In the event that historic land contamination is found at any time
    when carrying out works in relation to the development, it must be reported in writing immediately to the Local Planning Authority and
    all development shall cease immediately.

    Development shall not re- commence until such times as an investigation and risk assessment has been submitted to and approved in writing by the Local Planning Authority, and where remediation is necessary, a remediation scheme has been submitted to and approved in writing by the Local Planning Authority.

    Development shall only re-commence thereafter following completion of measures identified in the approved remediation scheme, and the submission to and approval in writing of a verification report.

    This must be conducted in accordance with DEFRA and the Environment Agency’s ‘Model Procedures for the Management of Land Contamination, CLR 11’ and the Essex Contaminated Land Consortium’s ‘Land Affected by Contamination: Technical Guidance for Applicants and Developers’.

    Reason – The site lies on or in the vicinity of a former works and gravel pit where there is the possibility of contamination.


    Informatives


    The applicant is advised that the site to which this planning permission relates is recorded by The Local Borough Council as being on or in the vicinity of land of potentially contaminative use, that was a works and gravel pit.

    Prior to the commencement of the permitted development, the applicant is advised to undertake a suitable and sufficient site investigation and any necessary risk assessment to ensure the land is free from significant levels of contamination.

    REASON

    The site lies adjacent to land with potentially contaminative uses and Environmental Protection wish to ensure that development only proceeds if it is safe to do so.

    This informative should not be read as indicating that there is any known danger from the former use of land in this locality.
    • Kate0408
    • By Kate0408 18th Apr 17, 2:18 PM
    • 15 Posts
    • 1 Thanks
    Kate0408
    • #4
    • 18th Apr 17, 2:18 PM
    • #4
    • 18th Apr 17, 2:18 PM
    We had nothing but errors and mis-information from our previous architect so are now going with a structural engineer to design foundations etc (my husband has worked with him previously, so knows he is good.)

    My worry is that he may be too thorough as very old school (not a bad thing).

    We have just wasted quite a bit of money through our naivety over the last year and don't want to keep throwing money down the drain .

    The SE says he needs the one borehole to test the soil for foundation design. He has not seen the advisory notes on the previous planning approval.
    • Kate0408
    • By Kate0408 18th Apr 17, 2:28 PM
    • 15 Posts
    • 1 Thanks
    Kate0408
    • #5
    • 18th Apr 17, 2:28 PM
    • #5
    • 18th Apr 17, 2:28 PM
    I should add that on our previous application, the architect had a colleague who did all the engineering calculations and designed the foundations. Building Regs were sent all this relevant info and they passed as follows:

    "THE COUNCIL NOW GIVES YOU NOTICE, in pursuance of Section 16 of the Building Act 1984, that the Notice is accepted, for the proposal detailed above.

    **No Conditions**"
    • tonyh66
    • By tonyh66 18th Apr 17, 2:29 PM
    • 965 Posts
    • 710 Thanks
    tonyh66
    • #6
    • 18th Apr 17, 2:29 PM
    • #6
    • 18th Apr 17, 2:29 PM
    have you asked the SE if a trial pit would be sufficient?
    • the_r_sole
    • By the_r_sole 18th Apr 17, 3:11 PM
    • 2,271 Posts
    • 1,133 Thanks
    the_r_sole
    • #7
    • 18th Apr 17, 3:11 PM
    • #7
    • 18th Apr 17, 3:11 PM
    so you have planning permission and building regs passed for the project, but you are asking a new structural engineer to redesign the foundations?
    Has the new structural engineer said that the original design is not sufficient for some reason?
    • Kate0408
    • By Kate0408 18th Apr 17, 3:13 PM
    • 15 Posts
    • 1 Thanks
    Kate0408
    • #8
    • 18th Apr 17, 3:13 PM
    • #8
    • 18th Apr 17, 3:13 PM
    We will be asking him in due course. I just wondered if anyone else had any experience of this and costs involved.

    I'm assuming a trial pit would be cheaper but we are built to our boundary so it would have to be at the front of our house, through the driveway.
    • Kate0408
    • By Kate0408 18th Apr 17, 4:04 PM
    • 15 Posts
    • 1 Thanks
    Kate0408
    • #9
    • 18th Apr 17, 4:04 PM
    • #9
    • 18th Apr 17, 4:04 PM
    Our original design was for a two-storey side extension, however we have had to shelve those plans as it's just too much money (more than we anticipated).

    The SE looked over the previous foundation design but would want to redesign them based on the revised design (only one-storey).
    • teneighty
    • By teneighty 18th Apr 17, 5:23 PM
    • 920 Posts
    • 627 Thanks
    teneighty
    Is this in England or Scotland?

    If it is England getting a structural engineer to design the foundations for a single storey extension is massive overkill. Unless you have been told to expect difficult ground conditions it will probably be a simple standard trench fill foundation 1 - 1.2 metres deep and 450 - 600 mm wide. The local Building Control Officer at the Council will probably be able to advise you as they spend most of their time looking at muddy holes for foundations and are a wealth of knowledge for the local ground conditions.

    As for the contaminated land, your house is already sitting on it so how bad can it be? That condition only really needs taking seriously if it is a new build on a former industrial site etc.
    • tonyh66
    • By tonyh66 18th Apr 17, 5:30 PM
    • 965 Posts
    • 710 Thanks
    tonyh66
    why not just keep the found design for the 2 storey build incase you want to do it in the future?
    • Kate0408
    • By Kate0408 18th Apr 17, 8:12 PM
    • 15 Posts
    • 1 Thanks
    Kate0408
    Thanks for your replies!

    Yes, we are in England (North Essex). The problem with using the original foundations is that our new SE does not want to put his name to them! When we showed various builders the foundation plan, they all thought it was way overboard and more complicated than need be.

    I think because we are built to our boundary and will require a retaining wall to that side, we just accepted that the foundations would be more tricky (we are also on a hill and our property abuts to next doors pathway which is approx 1metre above our property level).

    My husband is keen to use this SE as he feels confident the job will be done properly - however, I'd like to keep costs down if something is not necessarily required!
    • Beenie
    • By Beenie 18th Apr 17, 9:11 PM
    • 1,031 Posts
    • 1,108 Thanks
    Beenie
    I will follow this with interest. We too are in Essex and are wanting to build an extension (single storey).

    The builder we propose to use has mentioned that we are on 'terminal morain' and he won't know how to do the foundations until a SE has verified the soil type (shale, clay, whatever).

    We are still at application stage so will see what the Planning dept says.
    • Kate0408
    • By Kate0408 18th Apr 17, 9:46 PM
    • 15 Posts
    • 1 Thanks
    Kate0408
    Yes, I think Building Control is the next port of call for us. I will certainly keep you posted - I'm sure moving would be less hassle but we love where we are and suitable properties don't come up for sale very often!
Welcome to our new Forum!

Our aim is to save you money quickly and easily. We hope you like it!

Forum Team Contact us

Live Stats

5,266Posts Today

5,059Users online

Martin's Twitter
  • You're right, of course. How silly of me. After all, all my work is solely focused on my own personal circumstance? https://t.co/m6DHzFUjzg

  • RT @ARJMOR: @MartinSLewis It may well be kind of random, but the algorithm used has a bias to the unpopular seats.

  • It seems what Ryanair is saying is "don't pay and we leave you the seats we don't think people want and they're in the middle."

  • Follow Martin