FYI - I have noticed more and more posts about floor level surveys and I have commented on most, but one item I have failed to cover is having a good temporary bench mark (TBM). Anyone doing a floor level survey to document elevations for a home owner to use for future reference has to ensure their starting point (TBM) is not located on the object that your trying to monitor. Generally you can drive a nail in the base of a tree or drive a steel rebar down to below the frost line as your TBM. However in areas with high shrink/swell soils where everything moves up and down, like some parts of Texas, this may be problematic. In a case like this I would contact your local land surveyor for advice. To use a TBM just assign an elevation to it say 100.00 feet. Probably 99% of inspectors that do floor level surveys are only doing a relative elevation survey, in other words they set up their instrument or place their ZipLevel on the floor and call that spot zero elevation and all other readings are relative to that point, which is fine for a one-time survey. If your client wants you to come back a few years later you have to place your instrument in the same location, if not your comparing apples to oranges without doing some mathematical adjustments to all your readings. So at least document where you placed the instrument and what floor covering was there in case the vinyl flooring was replaced with plush carpet. So if you go out and buy a ZipLevel educate yourself and have a plan before you use it.
I know its dated but great post