GRADING CONTRACTOR ROCK DISCOVERY CHANGED CONDITION — DOCUMENTATION, CHANGE ORDER, AND PROTECTION.
Rock discovery during grading is a changed condition when the rock conditions materially exceed what the geotechnical report represented. The contractor who documents the discovery on day one, provides written notice the same day, and submits the change order before extensive rock removal has occurred collects for the additional cost. The one who discovers rock, removes it for three weeks, and then submits a change order from memory has a significantly weaker claim for the same scope.
SPM includes changed condition cost code setup and documentation protocols in every CFOS engagement for grading and civil subcontractors. The cost record starts from day one of any changed condition encounter.
HOW TO DOCUMENT IT, WHEN TO SUBMIT THE CHANGE ORDER, AND WHAT TO INCLUDE.
Why Rock Discovery Is a Changed Condition
A changed condition claim requires that the conditions encountered differ materially from what was reasonably represented in the contract documents. For rock discovery, the contract documents that establish the baseline are the geotechnical report (if provided), the boring logs, the subsurface investigation report, and any soil classification assumptions in the specifications. When the grading contractor encounters rock at depths, locations, or quantities materially beyond what these documents indicated, the additional cost of rock removal is a changed condition — not the contractor’s risk to absorb. Most commercial construction contracts include an explicit changed conditions clause. Even contracts without an explicit clause often include changed conditions protection under general law in the project jurisdiction.
What Must Be Documented From the Day of Discovery
Day of discovery: location of rock discovery, depth, approximate extent, comparison to the geotechnical report. Photograph the rock face. Record the boring log depths nearest the discovery location and the soil classification the report predicted. This establishes the baseline deviation. Every subsequent day: rock footage removed, equipment used, hours worked on rock removal specifically (separate from earthwork hours), blasting events if applicable (date, footage, yield), and disposal quantities. This daily record is the cost basis for the change order. If the record starts after two weeks of rock removal, reconstructing it is difficult and the change order is weaker.
What to Include in a Rock Discovery Change Order
Scope description: unexpected rock encountered at [location] at depths of [X] to [Y] feet, exceeding the geotechnical report’s predicted [Z] classification at this location. Quantity: estimated cubic yards of rock removal, based on dimensions documented in field log. Direct cost: specialized equipment deployment (rock drill, hydraulic breaker, blasting contractor), operator hours at applicable classification rate, disposal at higher-cost disposal facility, and schedule delay cost if additional time was required. Overhead at the project overhead rate. Profit at the bid markup rate.
THREE PRACTICES THAT MAKE THE ROCK CHANGE ORDER STICK.
The geotechnical report review at bid time: The single most effective protection against absorbing rock removal cost is reading the geotechnical report at bid time, flagging any boring logs that show rock or refusal at shallow depths, and including a specific rock excavation allowance in the bid or noting a unit price for rock removal in the bid qualifications. A unit price for rock removal in the bid is a changed conditions protection mechanism — it establishes the rate before the work starts rather than after the dispute begins.
FREQUENTLY ASKED.
