Asked on May 8, 2017

If you are trying to extend your patio with concrete how do you attach

LizJustmeWilliam

Answered

if you are trying to extend your patio with concrete how do you attach it to the house. I do not want to drill holes into the existing slab, it will nullify the warranty on the foundation on the house. What is the best way to make it look like it's part of the house.
3 answers
  • William
    on May 8, 2017

    It is definitely NOT OK to pour the slab against something established and firm like a footing. As the slab is floating on soil near the surface and subject to heaving, it will want to move up and down independently of the footing. If bonded to the footing, the slab being a lot weaker and less massive than the footing will crack away and crack itself in the process,

    Typically when concrete is poured against a house foundation, (never pour concrete against any siding IMHO, it invites trouble later) an expansion joint is set to the house. It can be cork, 1/2" thick by 4" tall set to the wall with short pins to hold it while pouring. There is a tar or asphalt impregnated expansion joint material too that may hold a straight line better with fewer fasteners.
  • Justme
    on May 8, 2017

    I agree with person above. Consider using a decking perhaps raised a few inches so it looks deliberate.
  • Liz
    on May 9, 2017

    Check with insurance agent, and/or local cty/city engineer. If installed incorrectly, and it causes to your foundation, you may not be able to file insurance claim.
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