Unknown Site Conditions in an Ontario Construction Contract

List: survey, geotechnical report, borehole logs, grading plan, environmental report, existing drawings and utility information.

Record: title, date, author and revision so both parties know what was used for pricing.

Identify: who arranged soil testing, test pits, surveys, environmental review and private utility locating.

Clarify: what inspection the contractor was expected to perform before submitting the price.

State: assumed soil type, groundwater condition, excavation depth, access, disposal route and bearing elevation.

Avoid: hidden assumptions that appear only after work starts.

Measure: excavation, export, imported fill, pumping hours, rock quantity, trucking and testing included in the price.

State: whether quantities are bank volume, truck volume, weight, hours or measured in place.

Define: a material physical difference from the identified baseline—not merely work that costs more than the contractor expected.

Exclude or address: estimating error, ordinary weather, inefficient means and methods and contractor-caused delay.

Require: prompt written notice before the condition is disturbed or concealed where safety allows.

Include: location, description, photographs, estimated effect and requested direction.

Permit: necessary emergency work to protect people, property, excavation and neighbouring lands.

Require: records of emergency labour, equipment, material and reason for immediate action.

Allow: reasonable time for the owner, engineer, geotechnical consultant or environmental consultant to inspect.

Avoid: removing all evidence before the owner can verify the claimed condition.

Require: photographs, survey, engineer direction, tickets, invoices, time sheets, pump logs and disposal records.

Connect: every claimed extra to the actual affected location and quantity.

Agree: who measures, when measurement occurs and what records control.

Use: survey volumes, scale tickets, truck counts, equipment hours or other stated methods.

Choose: pre-agreed unit rate, verified cost-plus, lump-sum change or another stated formula.

Define: labour, equipment, trucking, disposal, subcontractor charges, fee, HST and credits.

Require: reasonable alternatives such as revised footing elevation, local undercut, alternate disposal or approved reuse of material.

Protect: engineering, code, environmental and warranty requirements.

Show: actual delay to critical work, not simply elapsed calendar time.

Separate: condition-related delay from contractor delay, weather, late decisions and unrelated work.

Address: inaccurate owner information, contractor failure to review available reports, missed locates and known site history.

Avoid: assuming one party is automatically responsible without reading the complete contract and facts.

Record: condition, accepted remedy, estimated or final price, schedule effect and supporting documents.

Emergency exception: immediate protective work may proceed, but notice and records should follow promptly.

Provide: a route for technical review, record audit, negotiation, mediation, adjudication or other agreed process.

Separate: disputed unknown-condition charges from undisputed progress work where the contract and law permit.