General conditions are the costs of the site existing: the superintendent's time, the dumpster rental, the portable toilet, temporary fencing, floor protection, the final clean. They belong to the job, not to the business, so they're direct costs, but no trade's invoice carries them, which is why estimators forget them and why a delay is expensive. Three extra weeks on a job is three more weeks of every general-conditions line, with no revenue attached.
A worked number
A 16-week whole-house renovation: supervision $9,600, dumpsters $2,400, toilet $560, protection and cleanup $1,900, permits and inspections $1,700. General conditions $16,160, about 8% of the $210,000 contract. Slip to 20 weeks and the supervision and rentals add roughly $3,200, unbilled unless the delay was the client's and a change order says so.
The mistake it hides
Burying them in overhead. If dumpsters and supervision are in the overhead rate, a job that runs long looks fine on its own ledger and the damage shows up in the year-end net. As a cost code on the job, the same delay shows up on the job that caused it.
In Obra
Give general conditions its own cost code and record supervision, rentals and site costs against it on each project. The cost codes guide puts it first on the list for that reason.