We are planning to pour a slab on ground for three hangar bays. The slab is 35x9 meters and we have completed the initial excavation. Now, the level difference from one short side to the other is 10 cm. We have calculated that this results in a 0.16° slope. For practical reasons, we do not want to excavate further to achieve a perfectly level surface. Is there any problem with the casting, i.e., with the concrete starting to flow towards the lower level? We don't think so ourselves, but of course we want to be sure before we start.
I don't think so, but mention the situation to the concrete company when you order so they can choose a slightly sturdier mix if they think it's necessary. But - I wouldn't think it's a real problem.
Fill in where it's low, maybe?
Silly to cast it crooked from the start...
Silly to cast it crooked from the start...
Have you ever seen water flow to the deep end of a filled pool? Nope, and concrete is not going to defy gravity either..... Just make sure the shape holds then.....
....but doesn't it seem more expensive to fill up with concrete than with gravel?
....but doesn't it seem more expensive to fill up with concrete than with gravel?
I understood it as the cast slab would be cast with a slope.
10cm on 35m would mean about a 0.3% slope, which does not pose any problem. I have been involved in casting loading docks with a 1% slope. The problem you'll face is casting an even floor, I would recommend excavating and casting it flat. If you absolutely don't want to do that, the tip is to rent a rotary laser that can be set to a slope.