When schedules get compressed: how GCs turn staggered work into stacked trades, and what it costs subcontractors

You bid off the GC's baseline: plumbing rough-in, then electrical and mechanical, floor by floor, mostly finish-to-start with limited overlap. Crews, durations and price were sized to that plan.

Then the job falls behind for reasons outside your scope, and the recovery plan runs everything at once: duct, conduit and pipe on the same floors the same week, three trades competing for one ceiling. Your contract amount hasn't changed, but you're no longer building the job you priced.

It happens more than most subs realize, and the added cost often gets absorbed without being measured.

The baseline was the job you priced

Compare the baseline with the sequence, durations, crews and access assumptions in your bid and subcontract.

Two crews for a six-week rough-in came from that logic: staggered trades, finish-to-start relationships, reasonable durations. Change the logic and you change the labor plan behind your price. Compare the new sequence with the access and crew assumptions in your bid and subcontract.

How resequencing stacks the work

Watch for two changes, usually together:

• Durations get compressed. The GC shortens your activity to recover time lost elsewhere.
• The sequence changes. Finish-to-start or staggered relationships become start-to-start and multiple floors release at once, so all three trades work the same area at the same time.

In the field, that's duct on three floors at once, conduit across every level, two trades already in your ceiling. That's schedule compression. When holding the new dates takes added crews, overtime or extra shifts, it may also become acceleration.

What shared workspace does to productivity

This cost often disappears into the daily labor reports. With three trades in one ceiling, crews wait on each other, work around material and lifts, move tools between floors, and repair work damaged in the congestion. Tight staging and added safety restrictions slow it further.

Even with the same headcount, you install fewer feet of pipe, conduit or duct per labor hour than in a clean, properly sequenced area. That's loss of productivity, and it can be measured.

Quantify it the right way

A prospective time impact analysis can tie a change or delay to its effect on the schedule. A measured mile or other loss-of-productivity analysis can tie stacked trades and congestion to reduced output and added labor cost.

Two different impacts, measured separately: the schedule analysis covers time, the productivity analysis covers labor efficiency and cost.

The bottom line

Compressed or extended, the impact shouldn't vanish into your labor cost. Your price assumed the baseline sequence, durations, crew plan and access. When those change, your cost can too.

Your position depends on the contract, timely notice, reliable field records, and schedule analysis tying the change to the impact.

An independent scheduler on your side gives you a defensible baseline, changes caught as they happen, timely notices and real numbers behind the impact, so you can pursue added time and compensation instead of absorbing the cost.