The bid price for cast-in-place duct bank work rarely reflects the true cost to the project. Several significant costs are either buried in other line items or do not appear until the work is underway.
Idle crew time
When ready-mix trucks are late or canceled, 6 to 12 workers stand idle at full day rates. A single missed pour can cost thousands in wasted labor before any concrete is placed.
Schedule delays
Cast-in-place duct banks require 2 to 7 days of trench-open time per section — excavation, forming, pouring, curing, and backfill. Every day the trench stays open delays the trades behind it. On fast-track projects, duct bank delays cascade into electrical, mechanical, and civil schedules.
Weather resets
A rained-out pour does not just delay the duct bank scope — it resets the entire sequence. Forms may need to be rebuilt, the trench re-dewatered, and crews re-mobilized. These recovery costs are rarely captured in the original bid.
Material waste
Cast-in-place work generates significant waste from single-use lumber forms, over-ordered concrete, and rebar cutoffs. Precast manufacturing uses reusable steel molds and produces virtually zero concrete waste.
Supply chain risk
Ready-mix and flowable fill availability is unpredictable, especially during peak construction season. Precast duct banks arrive as finished products with no dependency on batch plant scheduling.
When evaluating duct bank approaches, comparing the bid price alone does not tell the full story. The total installed cost — including labor efficiency, schedule impact, and risk exposure — is where precast consistently delivers better value.