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Forming concrete for garage – best practice to keep rain out

mikeysp | Posted in General Questions on

Hi. In zone 4a I am getting ready to form up for a monolithic slab and want to identify the best practice for keeping rain water from getting into shop under garage door.

In the image below I illustrated two ides I have gathered from online images or videos. It seems the cutout method with maybe a 1″ drop would be best, but I am not certain.

Thank you for your advice.



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  1. walta100 | | #1

    Garage floors are sloped to drain to the door about 1/8 of an inch per foot, if you can maintain or increase that slop outdoors for next 20 feet.

    The details in your drawing will be unnecessary.


  2. krom | | #2

    Walter.. That is the theory but even with those slopes, or steeper, wind driven rain finds its way into my garage on a regular basis

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