Begin with the clearest possible base scope.
Contingency should not hide missing quantities, undefined finishes, or work everyone already expects.
Price known demolition, construction, materials, protection, trade work, access, disposal, and closeout first. Identify allowances separately. Then create a contingency suited to the age, documentation, access, investigation completed, and amount of concealed work.
List the risks behind the number
- Conditions hidden behind walls, floors, ceilings, cabinetry, or fixtures.
- Unknown substrate repair, moisture damage, or out-of-level surfaces.
- Existing plumbing, electrical, HVAC, structure, or fire-separation conditions.
- Building access, work-hour, delivery, disposal, or protection constraints.
- Design details or selections not final when the budget is prepared.
Separate owner changes
A decision to expand the scope, upgrade a product, move a completed item, or accelerate work is different from an unforeseen condition. Track owner changes separately so the contingency still shows how much capacity remains for project risk.
Use written release rules
Before contingency is used, record the condition, evidence, recommended response, cost, time effect, alternatives, and approval. Update a simple log showing the original amount, approved uses, pending exposures, and remaining balance.
Do not spend the remainder too early
Risks remain through rough-ins, substrate preparation, fixed-finish installation, testing, deficiencies, and closeout. Wait until exposure reduces before considering optional upgrades.