A moved slab edge scraps a bundle you already paid for
The bundle was cut for one building and one slab edge. Move that edge after fabrication release and roughly 100 coiled tendons become scrap with no credit memo behind them.
A drywall sub orders stock-length board and sends the leftovers back on the same truck. Post-tension has no stock and no return: the material is engineered to one structure's geometry and becomes scrap the moment that geometry changes. That's why the change-order clock on a PT job starts at the fabrication release and not a day later.
The size of it
One late slab-edge revision buys you a scrapped bundle plus an expedited re-fab, and when the change order wasn't written before the truck rolled, that number ends up in your material variance where the owner never sees it.
No published benchmark reference breaks this trade out on its own. CFMA reports at NAICS level, and at that level this trade rolls into a broader bucket with several others. That's why this page carries mechanisms and no margin figures. It reports inside NAICS 238110 Poured Concrete, so there's no post-tension margin figure to put in this box. The 48 trades that do publish average 7% net profit at $1M–$5M before taxes, which is the nearest reference point worth anything here.
Unbonded tendons are fabricated to unique lengths off the approved tendon layout, then shipped in bundles of about 100 coiled, color-coded strands on a flatbed. There's no stock tendon sitting in a warehouse for your job. When a slab edge moves, a stair opening gets added, or a column line changes after the fabrication release, every strand in that bundle is now the wrong length. Short strands are scrap. Long ones are a field problem at every live end, and the plant takes neither back for credit.
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 post-tension contractors money
The same mechanism in other trades
What post-tension owners ask
Who pays when the slab edge changes after tendons are fabricated?
The bundle was cut for one building and one slab edge. Move that edge after fabrication release and roughly 100 coiled tendons become scrap with no credit memo behind them.
What does it cost?
One late slab-edge revision buys you a scrapped bundle plus an expedited re-fab, and when the change order wasn't written before the truck rolled, that number ends up in your material variance where the owner never sees it.
What do I do first?
Put the fabrication release date for each PT job on your schedule and email the GC the day it locks: after that date, any slab edge, opening, or column line change is a change order with material and re-fab priced into it.
Are there published benchmarks for post-tension?
No, and this site won't print one. No published benchmark reference breaks this trade out on its own. CFMA reports at NAICS level, and at that level this trade rolls into a broader bucket with several others. That's why this page carries mechanisms and no margin figures. In the surveys it rolls into NAICS 238110 Poured Concrete, so the closest honest reference is the 48-trade table, where net profit at $1M–$5M averages 7% before taxes. Read that as the neighbourhood, and read your own job costing as the answer.
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.