The slab isn't dry and the mitigation bill is yours
The GC's schedule says flooring starts Monday. The slab has been enclosed eight weeks, the RH probes read north of 80, and the mitigation quote is sitting on your desk.
Every trade deals with schedule compression. Flooring is the only one whose product is bonded to the slab with an adhesive that fails when the substrate is wet, and whose warranty is written by a mill that will pull your RH documentation before it honors anything. Drywall goes up over a wet slab all day long; an epoxy moisture vapor barrier is a scope item that exists only because your material is the one thing the concrete can ruin.
The size of it
An epoxy moisture vapor barrier runs roughly $2 to $5 per square foot, so a 40,000 square foot package is $80k to $200k of scope nobody bid. It gets argued as a change order while a mobilized crew sits at full burden waiting for an answer.
The concrete was never going to be dry, and everybody on the job knows it except the schedule. ASTM F2170 wants the building at service conditions with HVAC running for 48 hours before probes go into the slab, then another 24 hours to equilibrate, so you've burned three days before you get a number. Concrete gives up water at roughly 30 days per inch, which means a 6 inch slab on grade wants about six months, and you get it at eight weeks because flooring got scheduled at month 18 of a 20 month build. Your manufacturer voids the warranty somewhere around 75 to 80 percent RH, so you're the only party on site who legally can't proceed and also the only party standing in the critical path. That combination is why the mitigation conversation ends up on your desk.
Three moves, in order
Step 06: Project management
Billing dates, change orders, and notices, run as standards that hold without anyone chasing them.
What else costs flooring contractors money
The same mechanism in other trades
What flooring owners ask
Who pays for slab moisture mitigation when flooring fails the RH test?
The GC's schedule says flooring starts Monday. The slab has been enclosed eight weeks, the RH probes read north of 80, and the mitigation quote is sitting on your desk.
What does it cost?
An epoxy moisture vapor barrier runs roughly $2 to $5 per square foot, so a 40,000 square foot package is $80k to $200k of scope nobody bid. It gets argued as a change order while a mobilized crew sits at full burden waiting for an answer.
What do I do first?
Pull your last three jobs and write down the slab pour date next to your scheduled install date. If that stretch is short of 30 days per inch of slab, you were always going to fail the test.
What are flooring contractors supposed to be making?
Flooring runs 19% gross margin, 14% overhead and 5% net profit before taxes at $1M–$5M. The all-trade average is 7%, so this trade sits 2 points below it. The CFOS target is 10%.
Which part of the system fixes it?
The step is number 06, project management. Billing dates, change orders, and notices, run as standards that hold without anyone chasing them. It comes from chapter 6 of CONTROL: The Construction Financial Operating System.
Josh Luebker ran commercial construction projects before he ran the numbers behind them, on data centres, military bases, hospitals, and high-rises. He wrote CONTROL: The Construction Financial Operating System, which is an eight-step framework for commercial subcontractors, and it publishes on October 1, 2026. He is a master electrician who moved into the office and kept the field vocabulary.
Sulphur Prairie Operations LLC maintains the benchmark reference behind these figures. Every edition is reconciled against the newest CFMA survey release before it publishes here. Where a figure changes between editions, the older edition keeps its year in the title so a citation to it stays correct.