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Comment by tlb | Hacker News Reader

14 inches over 58 stories works out to 0.10 degrees. That doesn't seem like enough to make anything roll. You might have to shim your billiard table.

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Your math is wrong. The relevant angle is not 14 inches over 58 stories, it is 14 inches over the horizontal length of the building.

I'm not sure what this. Guessing maybe 120 feet, e.g., gives a tilt of 180/pi * arctan(14/12/120) = 0.56 degrees.

Sorry, you are the one with the wrong math. The building is out 14 inches at the top. You divide that by the height to get the angle. What you calculated is the lean for a building which sank 14 inches on one side. That would be way worse - an excursion of [edit] 6 feet at the top.

A golf ball sounds like something to me:

https://www.youtube.com/watch?v=dCUCa0Bvh1k

Your floor being on a 0.1 degree slope is a rise of 0.2 inches over 10 feet. Definitely noticeable.

Not definitely. The professional standard for levelness in homes and office buildings is F_L ~ 20, where F_L is the levelness "F number".

http://www.concretefloors.ca/?page_id=546

http://www.betagroupgc.com/Concrete%20International%20-%20Th...

The maximum slope b=rise/run compatible with this is b_max = (314 mm/3m)/F_L = .105/F_L ~ 0.005 for F_L = 20,

https://www.astmfree.com/wp-content/uploads/2018/01/E-115-M....

which corresponds to 0.005 radians = 0.3 degrees.

Projects like roller rinks and warehouses that use air pallets require more level floors, but typically only by a factor of 2 .

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