Footage Stops Earning and the Box Rental Never Stops
Trench safety pays by the linear foot of centerline. Shields and slide rail cost by the calendar day, and that clock runs whether or not the pipe crew is waiting on an inspector.
Most trades buy the same unit they sell, quantity in and quantity installed, so a slow week drops revenue and cost together. You buy time and you sell distance, and the person deciding how long the trench stays open is the pipe crew foreman, not you. The pay application only reports footage, so the job reads healthy right up until the equipment days get totaled.
The size of it
A job at full bid quantity can still lose money on rental days, and it usually turns up at job close, months after anyone could have done something about it.
Trench safety is commonly bid and paid as a unit price per linear foot of trench measured along the centerline, manholes included. What drives your cost is equipment time: rental cycles on rented boxes, ownership cost on owned iron, both accruing on calendar days. When the pipe crew stalls for wet weather, a utility conflict, an inspector, or a GC sequence change, footage stops earning and the day count keeps running. You can finish at 100% of your bid quantity and still be underwater on equipment days.
Three moves, in order
Step 02: Equipment cost basis
A correct internal rate per machine covering ownership, maintenance, fuel, and transport, charged to the projects that used it.
What else costs shoring and shielding contractors money
The same mechanism in other trades
What shoring and shielding owners ask
How do I make money on trench safety per foot when the boxes rent by the month?
Trench safety pays by the linear foot of centerline. Shields and slide rail cost by the calendar day, and that clock runs whether or not the pipe crew is waiting on an inspector.
What does it cost?
A job at full bid quantity can still lose money on rental days, and it usually turns up at job close, months after anyone could have done something about it.
What do I do first?
Track two quantities on every trench job in the same report: linear feet set and equipment days consumed, by location.
What are shoring and shielding contractors supposed to be making?
No survey separates shoring and shielding, so there is no figure of its own. The nearest comparable trade in the reference is Excavation, which runs 21% gross margin, 14% overhead and 7% net profit before taxes at $1M–$5M, with a CFOS target of 10.5% net. Those are derived figures, not shoring and shielding's own. Read them as the neighbourhood, and read your own job costing as the answer.
Which part of the system fixes it?
The step is number 02, equipment cost basis. A correct internal rate per machine covering ownership, maintenance, fuel, and transport, charged to the projects that used it. It comes from chapter 2 of CONTROL: The Construction Financial Operating System.
Everything on this page is something you can install yourself, andCONTROL is the order to do it in. If you would rather buy the finished result, SPM The Construction CFO does this work for shoring and shielding contractors as a service. It is a separate firm, Sulphur Prairie Management, LLC, run by the same author.
Wrote CONTROL, the 8 step system behind these figures. More about the author.