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    How wide do extension footings need to be?


    Hello all,

    I am planning on some extension work and have not been able to find out how wide the footings for the foundations will need to be. I’ve been told they need to be 1 metre deep, but not how wide.
    Could anyone enlighten me on this, please?
    This will be a single storey extension on entirely flat ground.

    Asked by Adam on 11th Sep 2019
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    Best Answer

    leighs property services (NW)Ltd

    "Usually the inner course of block is 100mm then a 100mm cavity then a 100mm outer course plus you need to allow 150mm bearing each side. So in total 600mm. As for being a meter deep, you need to hit good ground, ideally clay!"

    Answered on 27th Jan 2020 - Member since Dec 2019 - report
    AliRay construction

    "The rule is 600 mm wide and 1.2m deep but it depends on the ground when you get to the depth."

    Answered on 2nd Feb 2020 - Member since Jul 2019 - report
    Multi Build

    "When dug out footings should be 1m deep x 500mm wide unless specified larger"

    Answered on 31st Mar 2020 - Member since Jul 2019 - report
    RB Builders limited

    If it's a double storey extension the footings will need to be 600mm wide. If it's a single storey then in some cases they will only need to be 450mm wide."

    Answered on 8th Jan 2020 - Member since Dec 2019 - report
    ian mccorquodale

    "The depth depends on what the ground is like you have to dig to solid ground.
    So if you have a solid ground like shallet you might only have to go down 450mm
    For a single storey building strip foundations will typically be 450mm wide and at least 200mm deep, and for two storeys 600mm wide and 200mm deep."

    Answered on 16th Sep 2019 - Member since Jan 2019 - report
    Easy build

    "It's best to make them 1 metre wide and build in the centre. May be overkill to some, but we always go 1 metre on footings width."

    Answered on 20th Dec 2019 - Member since Oct 2019 - report
    DRW Building

    "Hello, In West Oxfordshire we dig our footings 600mm wide."

    Answered on 31st Dec 2019 - Member since Dec 2019 - report
    EMA brickwork & property maintenance


    Almost all building control inspectors will ask for a minimum of 600mm wide and 1 metre depth for any size extension to a property.

    Hope this helps."

    Answered on 5th Jan 2020 - Member since Nov 2019 - report
    DNA Construction Services LTD

    "That depends on building control but usually 600mm wide and 1000mm deep."

    Answered on 21st Jan 2020 - Member since Jan 2020 - report
    Hillview services

    "These should be detailed in the engineers/architect drawings."

    Answered on 17th Feb 2020 - Member since Jan 2020 - report
    S&L Building Services

    "The footings need too be 1metre deep by 450 wide and that should be plenty"

    Answered on 15th Apr 2020 - Member since Dec 2019 - report

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