Differing site conditions: the clause for when the ground lies

FAR 52.236-2 covers subsurface or latent physical conditions that differ materially from what the contract indicated — but no request for adjustment is allowed after final payment. How changed-conditions claims work.

The bid priced the dirt as described. Then the excavation found rock, water, or debris that wasn't in the boring logs. In federal contracting, the differing site conditions clause — FAR 52.236-2 — exists for exactly this: it covers subsurface or latent physical conditions at the site which differ materially from those indicated in the contract, and unknown physical conditions of an unusual nature that differ materially from those ordinarily encountered in the type of work.

Two categories, one mechanism

• Type 1 — the documents were wrong: conditions that differ materially from what the contract indicated. The boring log said sand; the trench says rock.
• Type 2 — nobody could have known: unknown physical conditions of an unusual nature, materially different from what the work ordinarily encounters.
• The remedy is an equitable adjustment: the contractor notifies promptly, the government investigates, and if the conditions qualify, the contract is adjusted — in cost, in time, or both.

The deadlines are absolute

The clause's teeth are procedural: no request by the contractor for an equitable adjustment for differing site conditions shall be allowed if made after final payment under this contract. The claim dies with the last check — and it weakens with every day of delayed notice while the crew keeps digging through the very condition being claimed.

The claim is built on the day the condition appears

A winning DSC file is dated: photos of the condition before disturbance, the contract documents that indicated otherwise, the daily reports showing the work stopped or changed, the costs segregated from base scope — the same segregation a change order demands. That evidence, captured per job as it happens, is the operation an ERP for construction companies runs for a contractor, implemented around the way each company works.