Laser Leveling Slab Variation

Laser leveling for window and door alignment is critical to within 1/8" and always assume a MINIMUM 3/4" slab variation due to natural uneven curing. And I NEVER trust the shell guy's control line. I love this part of the process and really prefer to do a final field measure prior to releasing windows and doors into production for precise accuracy.

For over a decade I have been the one to take ownership of the control line process and establishing finished floor level and ceiling height with the GC and then dialing in the final window and door dimensions to align perfectly.

And I have seen some slabs vary by OVER 1-1/2", this one was 1-3/8" from the 59-1/2" high point to the 60-7/8" low point on the first floor, the 2nd floor was WORSE! You are going to have a high point somewhere in the middle of the slab and your perimeter slab where the door sills are is going to be lower.

If the flooring was intended to be a nominal 1-1/2" thick, this is going to often make it over 2" thick at the perimeter. Headers also tend to vary by 3/4" or so for all kinds of reasons and will reduce your level opening heights across the entire elevation if your ceiling is a consistent height throughout.