Etydhv

Many self-leveling lasers, including my Bosch GCL 2-160, have a limitation when used to level a ceiling or a floor: the horizontal laser beam often cannot get within several inches of the ceiling or floor due to where the laser emerges from the device.

This really slows things down for me when trying to grind down a high spot in a concrete floor, or trying to shim the ceiling strapping. My workaround typically involves getting the laser as close as possible to the surface I'm trying to level, and then using a tape measure to sample the distance from the laser to the surface at a bazillion different locations.

Are there any devices or techniques to make this less painful?

A good ol' scrap block of two-by does nicely. Just set your laser 1-1/2" above your slab height and kick the block around as you work.

This doesn't work for ceilings, of course, but hopefully you have fewer points to measure in that case. You'd have to use something with a suction cup or magnet otherwise.

That's actually the way one normally does such things, and has been since before there were lasers, other than one normally uses a rod rather than a tape for more consistent results. You establish a reference plane (Generally not going to any great lengths to try and get it super-close to the surface you are working), measure in a grid, and mark high spots for grinding (and/or low spots for filling.)

During the work you may use a marked stick rather than a graduated rod, where the stick is marked for the distance from the reference plane you are trying to achieve, so no math is needed, just a check against the stick to see if you are at the mark yet.

For typical floor or ground work, I generally keep the reference plane up around 30 inches, so I don't have to crouch way down to check, I can just bend over a bit and clearly see the mark. Putting it inches off the floor would be painfully annoying to work with, IMHO.

on ceiling drop lazes lower use block or tape i have a magnet that hangs down get bench mark sticks on so can use both hands.floor set up get stick shoot grade to hard if down low
way we did it works

Use a 2x2 of any suitable height. Pre-drill a hole in it (so it doesn't split), then screw in a lag screw about half its thread length. The lag screw goes down, to touch the surface being measured.

Then mark a line on the 2x2 at the appropriate height so the laser hits it right on the mark. If you find your mark is not quite in the right place, turn the lag screw in or out until it is.

If the laser is near the floor, you can also use it as a pass/fail, because either the laser will hit the bottom of the 2x2 (high enough), or it will not (too low).