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garage foundation.

Discussion in 'Building' started by 2019, 21 Jan 2019.

  1. 2019

    2019

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    I thought id start its own thread on this query i have concerning strip foundations of a garage.

    If the garage foundation will be a strip foundation 900 wide x 300 thick with 10mm wire mesh or rebar for a double skinned block walls with 100mm cavity, then later a 150mm slap poured with 10mm wired mesh for the floor area. This will be after the block footings have been built to dpc level.

    When digging out for the strip foundation, is there any need for digging out under where the roller doors are going. Im assuming there isnt any need for concrete there, but im open for correction!

    I have been considering adding another roller door on the side of the garage including the roller door on the gabled wall facing away from the house at my entrance. The garage openings will have a double steel beams or catnics for over the large openings for the doors.
     
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  3. Ian H

    Ian H

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    I’d have it myself, nice and strong where the car rolls in and out and another connection between the walls.
     
  4. 2019

    2019

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    This also crossed my mind but then id have to build up again with maybe block on flat for a strong base for the cars to drive over. At most, i think its 2.5 cubic meters of concrete and whatever block is needed.
     
  5. Ian H

    Ian H

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    I converted my garage to a room and there was no foundation in between.

    Just seemed a bit wrong to me for the sake of a bit of extra digging and concrete.
     
  6. 2019

    2019

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    If youve no foundation under one of your walls in the converted garage, whats holding the walls up?
     
  7. Notch7

    Notch7

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    900mm wide seems wide.

    Wouldnt you just do a conventional trench footing? Typically 450mm or 600mm wide x 1M deep.

    Depth of bottom of trench is entirely dependant on ground conditions, ie load bearing capacity of soil, shrinkability and any trees or hedges within zone of influence.
     
  8. 2019

    2019

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    Its the regs here where i am unfortunately! The ground conditions are good. 900wide x300 thick in a 600mm trench min regs. If its a single skinned wall, it can be 300 wide. Here the regs are whatever thickness your block walls are, you multiply by 3. The cavity plus 2 100mm block is 300mm, multiply that by 3 equals 900mm. Notch7, i agree it can be excessive but thats the regs and i have to follow them. What im wanting to know, is there any need to continue the strip foundation under where the roller doors will be.
     
  9. Ian H

    Ian H

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    I put one in before I built the wall.
     
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  11. Notch7

    Notch7

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    There probably isnt a need as such, but running the foundation across the door opening will certainly increase the strength a lot as there wont be any open ends. Any point load bearing on either side of the doors will be spread over a wider area of foundation.
     
  12. noseall

    noseall

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    There is no need for a foundation under the slab at the door detail. It could increase the risk of the slab cracking at this point. You are better off building a slab thickening toe at the point of impact, directly beneath the doors.

    The trench only need be 600mm wide for a standard 300mm wide cavity wall.
     
  13. 900 wide by 300mm thick reinforced concrete seems way of the top, 600 x 225m thick concrete are normal strip foundations for 300mm wide cavity walls here, but if your regs are different you have to work to them like you say.
     
  14. 2019

    2019

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    I agree bt the regs here for min strip is 3 times the width of the walls. 300mm thickness aswell. It is excessive but the more concrete, the better the foundation!
     
  15. 2019

    2019

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    One says better and the other says not better :( Im scratching my head now as to what one to choose!

    When you say the slab cracking, is this the actual strip foundation or the actual 150mm floor slab once that is poured.

    I googled slab thickening toe, i dont know what this is or ever heard of it.
     
  16. noseall

    noseall

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    [​IMG]

    [​IMG]
     
  17. 2019

    2019

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    I was thinking maybe this is what it was. This is how raft foundations are poured.
     
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