Creston Housing Hub

Garage Conversion to Secondary Suite

The following information is your guide for converting carports or garages into living spaces.

Building Permit Application Submission
  • Complete a building permit application
  • Fill out an Owner Authorization form (if a building contractor is the applicant)
  • Provide one (1) set of building plans at 11″x17″ and a digital copy emailed to – Drawings must show the existing structure, envelope assemblies, and proposed alterations (see drawing requirements below)
  • Submit a Site Plan showing adherence to the BC Building Code (BCBC) and Town of Creston Zoning Bylaw
  • Submit Form Schedule B (mandatory for construction projects not covered by part 9 of the BC Building Code and requiring the involvement of a Professional Engineer).
    1. Lot shape and size with setbacks from dwelling to property lines and pre-existing or proposed structures
    2. North-facing arrow
    3. Any easements, right-of-ways, or watercourses;
    4. Any and all structures on the lot
  • Foundation/Floor Plan to show foundations necessary in supporting new infill or additional structures; method and construction for all assemblies (sheathing, sleepers, insulation, membranes, etc.)
  • Existing layout and assemblies
  • New floor layout identifying new rooms with dimensions, doors, windows, smoke alarms, plumbing fixtures etc.
  • Cross Section plan to show all construction components and details; including, but not limited to:
    1. Sub-floor framing
    2. Exterior wall and ceiling framing/ cladding/ insulation.
  • When exterior walls are constructed to create an interior space, they shall be supported by a concrete foundation.
  • The concrete foundation must extend a minimum of 30″ below finished grade for frost protection.
  • The new floor must be level. This may be done either with a wood floor constructed of plywood and tapered
    pressure treated sleepers or a second concrete slab, poured over the existing slab.
  • A damp-proofing membrane is required over the existing slab prior to the placement of either type of floor described above. 
  • Framing materials must be protected from contact with concrete by either an approved membrane or be made of pressure treated material.
  • Provide a minimum of 150mm (6″) clearance between cladding and finished grade – 200mm (8”) if the cladding is adversely affected by moisture.
  • A minimum of 2.0m (6’ 7”) clear height is required throughout the new floor space
  • Door(s) to the new interior space from the exterior, must be exterior grade and weather stripped, complete with a threshold.
  • If a window is added to the new exterior wall and faces an adjacent property, the window size will need to be approved by a Building Official for Spatial Separation.
  • If a bedroom is planned for the new interior space, it will require a window for emergency egress. The minimum openable portion of the window is 3.75sqft (0.35m2) in area, with no dimension less than 15” (380mm).
  • New or existing exterior walls encompassing the newly created interior space shall be insulated to a minimum effective thermal resistance of R15 (2.78 RSI).
  • Electrical boxes in all exterior walls and ceilings adjacent to an attic space are to be the “gasket sealed” type.
  • Unheated floors that are above the frost line and have no embedded heating pipes, cables, or ducts shall be insulated to a minimum effective thermal resistance of R12 (1.96 RSI).
    1. This insulation is to be applied either beneath the newly leveled slab or within the pressure treated sleepers, a distance of not less than 4’ (1.2m) horizontally along the perimeter of the floor.
    2. In addition, if a new slab is poured, a thermal break between the edge of the slab and the foundation wall is required. This thermal break must have an RSI value at least 50% of the required insulation.
  • The roof space over the newly created interior shall be insulated to a minimum effective thermal resistance of R40 (6.91 RSI). The attic space must be vented; a minimum of 1/300.
  • For low pitched or flat roofs, the minimum Insulation value is R28 (4.67 RSI) and must be provided with ventilation; a minimum of 1/150
  • Ventilation is to be arranged so that at least 25% of the ventilation is at the top and 25% at the bottom (soffit/ridge vents) of the roof space.

The inspections required will depend on the scope of work taking place.

  • Inspections must be requested by the owner of the property or their authorized agent.
  • All work for the inspection being requested must be completed and ready.
  • Work must not proceed past any of the stages listed without first being approved by the Building Official.
  • The street address and permit sheet must be posted in a visible location on the site.
  • The approved permit drawings must be available on site for all inspections.
    1. Siting & Foundation Inspection: occurs upon completion of any necessary concrete form work, prior to placing concrete.
    2. Rough-in Plumbing Inspection: occurs once all drains, waste pipes, vents, and water piping have been completed and tested.
    3. Framing Inspection: Occurs when all frame work, sheathing, electrical wiring, and plumbing rough-ins have been completed. Exterior cladding or insulation is NOT to have been installed at this time.
    4. Insulation Inspection: Occurs when the thermal insulation and vapor and air barrier are completed, prior to drywall. Note: Building paper or house wrap must be applied at this time to protect the insulation from weather.
    5. Final Inspection: Occurs once all construction is complete.

Separate electrical and gas permits are required for a new build or modification to the existing systems and are to be obtained through Technical Safety BC.