acceptable slope for concrete slab in garage floor

Old 04-02-19, 03:37 PM
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acceptable slope for concrete slab in garage floor

The sloping concrete slab for our 8' garage addition is driving me crazy. Tools on rollers freely roll down the floor unless you block the wheels. The floor slopes about .875" over 4' or about 1.015 degrees. (rhetorical question first)
Was the floor poured incorrectly or the ground not prepared right?
Is there anything to do about it?
It's probably not worth the cost. But we do see cracks in the mortar between the stones where the addition was added.
Old 04-02-19, 03:57 PM
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It all depends on how the space is to be used. Most of my shop floor is flat, except when you get close to the floor drains, where it gently slopes to the drain. And I like a flat floor in this case because it makes it easier to position outfeed extensions, roll toolboxes, etc. I have a buddy who has something in the vicinity of 40 vintage cars and trucks, so he has a couple of bays where he wants the wash water to drain and has something like you do, maybe more. So was it poured incorrectly? Who knows; maybe it is exactly what they wanted. But the fact that it slopes that much is not by itself indicative of failure, if that's your concern, My own attached garage, which I did not design and build, is around what you're describing, and yes, for general use it seems a bit excessive. To me, if you are going to carry in snow or whatnot, and want it to drain someplace, a good target is around 1/8 per foot. But, ideally, you'd probably come out flat for about 3' or so off the walls, in order to leave a flat area for benches, shelving, or whatever. As far as a cure, replacement is the only long term option, and that would be very costly.
Old 04-03-19, 04:22 AM
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This is normal for most garages. Use shims to level out benches and cabinets.
Old 04-03-19, 04:32 AM
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If it was an addition I assume the slab was poured to meet something existing at either end. One end of the slab was determined by the height of your existing garage floor. The other end was probably dictated by the level of your driveway. Before the addition you probably didn't notice the slope in your drive but now that it's part of the garage you notice it more.

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