The answer

There is no safe universal percentage. Build contingency from project uncertainty: age and records, concealed assemblies, active defects, design completeness, demolition, hazardous materials, structural or service changes, permit uncertainty, allowances, procurement, occupied-home logistics and schedule. Keep contingency separate from known scope and maintain an untouched household or property reserve; reduce or phase scope when the downside case is unaffordable.

Calgary-specific context

An older inner-city home with structural, envelope and service work needs a different uncertainty allowance than a documented cosmetic condo update.

What to do next

Price low, base and high outcomes and identify the exact event that consumes each contingency line.

Related guides

Scope, contractor, permit, budget, construction, inspection, and resale guideCalgary Home Renovation and Remodeling DecisionsAn end-to-end Calgary renovation system for kitchens, bathrooms, basements, additions, structural changes, windows, exterior work, electrical, plumbing, gas, HVAC, accessibility, energy upgrades, condo projects, and whole-home remodels. Define the outcome, investigate the existing property, control design and scope, verify contractors, confirm permits, contract and fund safely, manage occupancy and changes, inspect hidden work, close deficiencies, preserve warranties and build the records a future insurer, lender, appraiser, buyer, lawyer, or owner can trust.Decision playbookCalgary Home Renovation Project-Control PlaybookCalgary Home Renovation Project-Control Playbook for Calgary homeowners, condo owners, landlords, buyers, sellers, families, and investors planning, contracting, funding, managing, rescuing, or documenting a residential renovation: Choose investigate, design, permit, quote, contract, fund, phase, build, inspect, correct, close out, reduce scope, defer, change contractor, sell as-is, or stop before an irreversible commitment.Interactive toolCalgary Home Renovation Project PlannerPressure-test a Calgary renovation from property baseline and active defects through design, contractor verification, permits, contract, budget, financing, schedule, occupancy, changes, inspections, payments, closeout, resale records, and failed-project fallback.

Verify before relying

Official sources for this topic

These sources explain the rules and records relevant to this topic. Check the current requirements for your property.

City of Calgary home-improvement permitsRead the current official guidance and confirm what applies to your property.City of Calgary hiring a contractorOfficial Calgary contractor business-licence, written-contract, permit, insurance, WCB, reference, payment, and project-protection guidance.City of Calgary homeowner trade permitsOfficial Calgary rules for homeowner and contractor electrical, plumbing and gas permits, qualifications, rough-in and final inspections, and concealed work.City of Calgary inspections for homeownersOfficial Calgary building and trade inspection booking, outcomes, existing-construction, concealed-work, and post-inspection pathway.City of Calgary inspection timelinesCurrent Calgary building, trade and development inspection capacity reporting and inspection-service context.City of Calgary property researchOfficial Calgary pathway for current and historical permit, plan, inspection and planning-related property records.City of Calgary certificate of complianceOfficial Calgary guidance explaining RPR and Certificate of Compliance scope, applications, encroachments, and the separate need to verify permit history.Alberta hiring a contractorOfficial Alberta consumer guidance for contractor identity, qualifications, insurance, written estimates, contracts, payment, and complaints.Alberta prepaid contracting licenceOfficial Alberta definition, licensing, security, contract, invitation and consumer requirements for qualifying prepaid contractors.Alberta prompt payment rulesOfficial Alberta prompt-payment, proper-invoice, non-payment notice, holdback, adjudication and construction-lien framework.Alberta Land Titles construction lienOfficial Alberta construction-lien forms, dates, registration, cancellation and statutory pathway.WCB Alberta clearance lettersOfficial WCB-Alberta contractor coverage and account-standing clearance pathway before work and payment.Alberta condominium informationOfficial condominium law, document, insurance, bylaw, reserve-fund, and ownership information.Alberta asbestos project notificationOfficial Alberta occupational-health pathway for renovation or removal work that may release asbestos fibres.RECA property condition, disclosure and title guidanceRead the current official guidance and confirm what applies to your property.CREB housing statisticsPublic Calgary market report hub.Law Society of Alberta lawyer directoryOfficial Alberta directory for checking lawyer status and searching by location, practice area, language, and other criteria.

Check the current information at the linked source. Ask the appropriate professional how it applies to your property.

Important

This is general information, not legal advice. Speak with a qualified lawyer about your specific situation.

RELATED GUIDES / Condition & upgrades

Find the right inspection for the property.

A visual inspection cannot clear concealed defects or identify hazardous materials reliably. Ask what was inaccessible, which tests are excluded and which qualified specialist should assess the concern before work or condition removal.

Official verification: Health Canada: asbestos precautions ↗

Affiliated network resources provide context. Confirm rules, approvals and property records with the responsible authority.