Choose a contingency that matches the unknowns

Name the unknowns before selecting a reserve

A project with complete selections and accessible existing conditions has a different uncertainty profile from a renovation planned from photographs. Start a risk list with the designer and contractor. Ask what they could not inspect, what the estimate assumes, and which decisions remain open.

Useful headings include concealed conditions, incomplete drawings, uncertain quantities, unresolved selections, site access, utility coordination, and schedule exposure. Describe the specific concern under each heading. “Existing drain route not verified” gives the team a question to investigate; “old house risk” does not.

Separate three kinds of money

Keep the current defined scope, allowances, and contingency in separate columns. An allowance is an identified scope item with an unsettled cost. A contingency is a reserve for uncertainty. An elective upgrade is a new choice. Combining all three makes it hard to tell whether the project is becoming more expensive or simply more defined.

For each risk, record the possible cost or time consequence as a range supplied by the relevant professional, the next investigation, and the person responsible. Where no defensible range exists, mark it unpriced rather than entering a reassuring zero.

• What evidence would narrow this uncertainty?
• When will the information become available?
• Could several risks occur together?
• Would the household still be comfortable with the downside case?

Spend on information where it changes the decision

A survey, targeted professional investigation, or completed selection may clarify a costly assumption before construction. Ask what the investigation can establish and what will remain concealed. Investigation itself has a scope and cost; it does not guarantee that every condition will be found.

Compare the cost of obtaining information with the decision it enables. If an unresolved condition could change whether the project is affordable, investigate before committing to optional finishes. If an issue cannot be resolved until approved opening-up work, agree how it will be documented, priced, and authorized when found.

Reconcile the reserve as work progresses

Maintain a reserve ledger with the opening balance, approved use, unresolved exposure, and remaining balance. Review it alongside committed costs and the forecast to finish. Money left in the bank may already be needed for an outstanding invoice or a known change.

Release reserve cautiously as risks are actually retired. Finishing demolition does not automatically resolve later procurement or completion issues. If the forecast exceeds available funds, consider scope changes while choices remain possible. A universal contingency percentage cannot replace this conversation; the right planning amount depends on the evidence, project maturity, financing constraints, and the owner's tolerance for uncertainty.