Build a garage

Attached, detached or workshop garage: siting, slab, framing, fire safety, heating, ventilation, electrical and EV charging.

Limit

Large openings, fire separations, loads, heating and electrical work often require permits and professional design.

Project types

  • Attached
  • Detached
  • Carport
  • Single
  • Double
  • Workshop
  • Room or dwelling above

Scope to coordinate

  • Setbacks, height, area, access and drainage
  • Turning radius, slope, snow and door threshold
  • Monolithic slab, foundation or piles
  • Drainage, insulation, vapour control and under-slab conduits
  • Headers, braced walls, trusses and overhead storage
  • Garage-house separation and CO protection
  • Heating, ventilation, lighting, tools and EV charger
  • Door, opener, seals, corrosion and maintenance

Critical controls

  • Validate use and siting before buying a plan.
  • Inspect base, reinforcement, anchors and conduits before concrete.
  • Never alter trusses or load attic storage without documented capacity.
  • Test door, detection, ventilation and equipment before use.

Potential participants

  • Municipality
  • Surveyor as required for siting
  • Engineer for soil, structure or large doors as warranted
  • Concrete/framing contractor
  • Authorized electrical and heating/ventilation specialists
Common method

Six phases with project-specific application

1
Feasibility and diagnosis Confirm constraints before committing to the project.
Application to this project: Use, siting, access and permits

Work and decisions

  • Define the need, future use, budget limits and performance target.
  • Survey the existing building or site, services, water, access and known risks.
  • Check zoning, permits, easements, environment and required professionals.
  • Separate confirmed facts, assumptions and unknowns in a dated register.

Hold points and controls

  • No irreversible purchase or contract before confirming major constraints.
  • A map, nearby borehole or verbal opinion does not replace project-specific verification.

Records to keep

  • Baseline surveys and photos
  • Authority responses
  • Risk and assumption register
2
Design, coordination and budget Turn needs into measurable coordinated scope.
Application to this project: Soil, slab, drainage and interfaces

Work and decisions

  • Coordinate architecture, structure, enclosure, plumbing, electrical, ventilation and drainage.
  • Select products and quality levels with acceptable alternatives.
  • Build a trade budget including fees, permits, tax, contingency and financing.
  • Create a schedule with dependencies, procurement and inspections.

Hold points and controls

  • Review drawings and interfaces before tender.
  • Do not compare prices without common scope and explicit exclusions.

Records to keep

  • Coordinated drawings and details
  • Specifications and inclusion-exclusion matrix
  • Baseline budget and schedule
3
Permits, contracts and mobilization Clearly assign approvals, responsibilities and protections.
Application to this project: Contracts, door, structure and procurement

Work and decisions

  • Submit required documents and track permit conditions.
  • Verify licences, insurance, references, subcontractors and capacity.
  • Define payments, changes, holdbacks, warranties and closeout deliverables.
  • Plan safety, occupant, neighbour, water, dust and access protection.

Hold points and controls

  • No start without applicable approvals and issued-for-construction documents.
  • No verbal change without written scope, cost and time.

Records to keep

  • Permits and conditions
  • Contract and appendices
  • Quality, safety and inspection plan
4
Concealed work and hold points Control elements that are difficult to correct after concealment.
Application to this project: Concrete, framing and concealed work

Work and decisions

  • Inspect soil, excavation, reinforcement, anchors, drainage and conduits before concrete or backfill.
  • Verify load paths, connections, bracing and temporary shoring.
  • Coordinate rough systems and penetrations before insulation or drywall.
  • Photograph each concealed element with location and scale.

Hold points and controls

  • No concealment without planned inspection and resolved deviations.
  • Stop immediately for unexpected water, soil, bearing or material.

Records to keep

  • Inspection and test reports
  • Pre-concealment photos
  • As-built record of concealed work
5
Enclosure, systems and commissioning Make the building watertight, functional, balanced and testable.
Application to this project: Enclosure, fire, mechanical and electrical

Work and decisions

  • Verify continuity of water, air, insulation and flashing layers.
  • Test plumbing, drainage, electrical, heating, ventilation, controls and safety.
  • Complete balancing, settings, leakage tests and corrections.
  • Protect sensitive materials until temperature and humidity are suitable.

Hold points and controls

  • Approve mock-ups and critical details before repetition.
  • No equipment acceptance without commissioning and service access.

Records to keep

  • Commissioning reports
  • Product data and settings
  • Equipment and serial number list
6
Closeout, warranties and follow-up Deliver documented maintainable work with seasonal follow-up.
Application to this project: Closeout, maintenance and load restrictions

Work and decisions

  • Inspect by space and system with photos, owner and due date.
  • Obtain closed permits, as-builts, manuals, warranties and training.
  • Reconcile budget, changes, credits, holdbacks and final balance.
  • Plan maintenance, warranty review and inspection after rain, freeze or heating season.

Hold points and controls

  • No acceptance without dated deficiencies and critical deliverables.
  • Keep an exported copy of the file outside the browser.

Records to keep

  • Deficiency list
  • Closeout file
  • Maintenance and warranty schedule
Concept quantities

Preliminary garage calculator

Results compare options; they do not size the structure or authorize a concrete order.

Related tools

Always confirm applicable permits, professions, insurance and code editions.

Garage deep dive

Build a durable, dry and usable garage

Important: The existing calculator compares options; it does not size foundation, structure or drainage.

Scenarios to compare

  • 12×20: small vehicle/workshop; verify clearances, storage and door before locking size.
  • 20×20 or 24×24: two vehicles only if circulation, doors, storage and equipment remain realistic.
  • 24×30 and larger: program, structure, drainage, heating and budget change quickly.

Dry winter garage

  • Site and slab grading must keep water from returning toward the building or door.
  • Do not make a heated garage simply 'airtight': control humidity, ventilation, separation from the house and condensation.
  • Salt, snowmelt and wet vehicles demand drainage, durable materials and maintenance.

Construction record

  • Photograph foundation, reinforcement, drains, anchors, air barrier, flashings and systems before covering.
  • Keep permits, plans, reports, invoices, warranties and equipment models.