General & Code

Ontario Building Code (OBC)

The provincial building code that governs all construction in Ontario, enforced by municipal building departments through the permit and inspection process.

The Ontario Building Code is a regulation under the Building Code Act that sets minimum standards for building design, construction, and alteration in Ontario. It is divided into Part 9 (houses and small buildings) and Part 3 (larger buildings). Residential carpentry falls under Part 9. The OBC is updated every few years; the current version in force for residential work in 2026 is the 2012 Building Code as amended. Municipal building departments enforce the OBC through permits and inspections.

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Frost depth

The maximum depth below grade that soil freezes in winter, which every permanent footing in Ontario must reach to prevent frost heave.

Frost depth is the depth to which the ground freezes in the coldest part of winter. In Ontario it varies from 0.9 metres in the southernmost GTA to 1.8 metres in Northern Ontario; for most of the GTA, OBC 9.12.2.2 requires footings to reach 1.2 metres (about 4 feet). Any footing that sits above the frost line will heave and settle with seasonal freeze-thaw cycles, cracking the structure above. This is why a deck footing (helical or sonotube) cannot simply sit on a concrete pad poured on the surface.

Building permit

A municipal authorization to start construction, required under the Ontario Building Code for any structural, electrical, plumbing, or scope-defined work.

A building permit is a document issued by a municipal building department authorizing construction to start. In Ontario, a permit is required under the Building Code Act for any new building, structural modification, load-bearing wall change, addition, and certain electrical and plumbing work. The application includes stamped drawings, a site plan, and a permit fee ($180 to $1,500 CAD depending on scope and municipality). Permits in the GTA are typically issued in 10 to 20 business days for small residential scope.

Related: ontario deck permit rules 2026

Building inspection

A municipal visit during construction at which a building inspector confirms the work matches the permitted drawings and the Ontario Building Code.

A building inspection is a site visit by a municipal building inspector during defined stages of a construction project. For a residential addition, typical inspections are footings, framing, insulation/vapour barrier, plumbing rough-in, electrical rough-in, and final occupancy. The inspector checks against the stamped drawings and the Ontario Building Code. A failed inspection must be corrected and re-inspected before the next stage can proceed.

Framing & Structural

LVL beam (laminated veneer lumber)

An engineered wood beam made of thin wood veneers glued together with grain running in the same direction, used for long structural spans in residential construction.

A laminated veneer lumber beam is manufactured from 1/10 inch to 1/8 inch thick wood veneers bonded with waterproof adhesive under heat and pressure, with the grain of every veneer running lengthwise. LVL beams are typically 1.75 inches thick per ply and come in depths from 5.5 to 18 inches. In residential load-bearing wall removals they are bolted together in 2 or 3 plies to carry floor and roof loads across spans of 12 to 24 feet. LVL is lighter than steel, easier to cut on site, and usually 30 to 60 percent cheaper for the same span.

Glulam (glue-laminated timber)

A structural wood member made of dimensional lumber laminations glued together, used where both structural capacity and visible wood appearance matter.

Glued-laminated timber consists of graded dimensional lumber (usually 2x6 or 2x8) stacked and bonded with waterproof structural adhesive. Unlike LVL, glulam uses full-thickness lumber and has a visible wood grain that can be left exposed in a finished ceiling. Glulam is used for exposed beams in cathedral ceilings, post-and-beam additions, and decorative structural applications. It costs 2x to 4x LVL per linear foot for the same load capacity.

Load-bearing wall

A wall that carries weight from the roof, a floor above, or another wall, and cannot be removed without engineered replacement by a beam or post.

A load-bearing wall is any interior or exterior wall that supports structural load from above. The three reliable tells that a wall is bearing are: floor joists above run perpendicular to the wall, the wall stacks directly over a beam or foundation below, or another wall sits directly above it on the next floor. Removing a load-bearing wall requires a structural engineer's stamp, a municipal building permit under Ontario Building Code Part 9, temporary walls during the swap, and a beam and post system to carry the load the wall was carrying.

Header

A horizontal structural member above a door or window opening that carries the load that would otherwise pass through the missing wall studs.

A header is a beam installed above a framed opening (door, window, archway) that transfers the load from above around the opening to the jack studs on either side. In residential framing, headers are typically built from two 2x10s or 2x12s sandwiched with 1/2 inch plywood, or from a single LVL or PSL for longer spans. Ontario Building Code requires header sizing based on span, load, and whether the wall is bearing. An undersized or missing header is a common source of sagging windows and doors that won't close.

Sistering

Attaching a new joist, rafter, or stud next to an existing damaged or undersized one to add structural capacity without removing the original.

Sistering is a structural repair technique in which a new piece of dimensional lumber or LVL is nailed, bolted, or glued alongside an existing member that is damaged, split, or undersized. A sistered joist must run the full length of the original (or at least from bearing to bearing) and be through-bolted at specified intervals to transfer load. Sistering is common for repairing cracked floor joists, strengthening undersized framing discovered during renovations, and adding capacity under new loads.

PEng (Professional Engineer)

A licensed structural engineer in Ontario whose stamp is required on drawings for any load-bearing modification, new structural design, or work outside OBC Part 9 deemed-to-comply provisions.

A Professional Engineer (PEng) is licensed by Professional Engineers Ontario (PEO) and carries the legal authority to seal structural drawings. In residential carpentry, a PEng stamp is required on any drawing submitted for permit that involves load-bearing wall removal, new beam installation, major structural modification, or any structure outside the standard prescribed by OBC Part 9. PEng fees for residential work in the GTA run $650 to $2,500 depending on scope.

Simpson Strong-Tie

The dominant North American brand of structural connectors — joist hangers, post bases, hold-downs — required by engineered drawings for code-compliant framing connections.

Simpson Strong-Tie is the brand name for a full line of galvanized and stainless structural connectors used to join framing members in ways dimensional lumber alone cannot achieve. Common residential parts include LUS joist hangers, HUS/HGUS heavy hangers, LSTA straps, HDU/HDQ hold-downs, and ABU post bases. Engineered drawings in Ontario typically call out specific Simpson parts by catalogue number. Substituting parts without engineer approval voids the stamp.

Decks & Patios

Helical pile

A steel shaft with a welded helix that is driven into the ground hydraulically to bear a structure's weight, used instead of a poured concrete footing.

A helical pile is a galvanized steel shaft, typically 2.875" to 3.5" in diameter, with one or more helix-shaped plates welded near the tip. It is installed by a specialist crew with a hydraulic drive head on a skid steer or mini excavator, driven into undisturbed soil below the frost line until the installer's torque gauge reaches the engineered value. In Ontario that means below 1.2 metres for most of the GTA under OBC 9.12.2.2. Helical piles carry decks, additions, and small structures without the cure time of concrete and with no spoils to dispose of.

Sonotube

A cardboard tube formwork used to pour a concrete footing column for a deck or small structure, named after the Sonoco brand.

A sonotube is a heavy cardboard cylinder set vertically in an excavated hole and filled with concrete to form a column-shaped footing. In Ontario residential work, sonotubes must bear on undisturbed soil below frost depth (1.2 m in most of the GTA), with a bell or pad at the base in some municipalities. Sonotubes are the traditional alternative to helical piles; they are cheaper in material cost but more labour-intensive and cannot bear load until the concrete has cured for several days.

316 stainless steel (hardware)

A marine-grade stainless steel used for structural fasteners in contact with pressure-treated lumber, cedar, or composite decking to resist corrosion for 25+ years.

316 stainless is an austenitic chromium-nickel-molybdenum alloy that resists corrosion from chlorides and the copper-based chemistry used in ACQ pressure-treated lumber since 2004. In Ontario residential deck work, 316 stainless is specified for every fastener in direct contact with cedar, PT, or composite decking — joist hangers, deck screws, post-to-beam connectors, lag bolts. The cost is roughly 3x hot-dip galvanized, but it prevents fastener-driven rot, streaking, and structural failure over a 25+ year deck lifespan.

Pressure-treated lumber (PT)

Softwood lumber impregnated with preservative under pressure so it resists rot, insect damage, and moisture, used for deck framing, ledgers, and exposed structure.

Pressure-treated lumber is dimensional softwood (usually spruce-pine-fir or southern yellow pine) placed in a pressure chamber and infused with a wood preservative. In Canada since 2004, the standard treatment chemistry is alkaline copper quaternary (ACQ), which replaced chromated copper arsenate (CCA) for residential use. PT lumber lasts 25 to 40 years in ground contact and is code-compliant for deck framing. Its copper chemistry is corrosive to ordinary galvanized fasteners, which is why 316 stainless is specified in contact points.

Alkaline copper quaternary (ACQ)

The copper-based wood preservative that has replaced CCA in Canadian residential pressure-treated lumber since 2004.

Alkaline copper quaternary (ACQ) is the standard preservative used in residential pressure-treated lumber sold in Canada. It contains copper oxide and a quaternary ammonium compound as co-biocides. ACQ replaced chromated copper arsenate (CCA) for residential use in 2004 because CCA contained arsenic. ACQ is safe for residential handling, but its high copper content is corrosive to ordinary galvanized steel fasteners — hence the requirement for 316 stainless hardware in contact points with ACQ lumber.

Western red cedar

A naturally rot-resistant softwood used for premium decking, siding, and trim, prized for stability, colour, and workability in Ontario climate.

Western red cedar (Thuja plicata) is a softwood native to the Pacific Northwest. Its heartwood contains natural oils and thujaplicins that resist rot, insects, and decay without chemical treatment. Cedar is prized for residential decking in Ontario because it is dimensionally stable through freeze-thaw, takes penetrating oil stain cleanly, and has a warm red-to-amber colour. Kiln-dried clear western red cedar runs $4 to $8 per board foot at Ontario lumberyards in 2026 and has an honest 20 to 25 year lifespan as a deck top with annual stain.

Composite decking

Engineered decking boards made from wood fibre and plastic (HDPE or PVC) that require no stain or sealant and typically last 25 or more years in Ontario climate.

Composite decking is manufactured from a mix of recycled wood fibre and high-density polyethylene (HDPE) or polyvinyl chloride (PVC). Boards are co-extruded with a harder capstock layer that resists stains and fading. Major brands in the Ontario market are Trex, TimberTech, and Fiberon. Composite boards must be installed on joists at 12 inches on centre (not the standard 16), are installed with proprietary hidden fasteners, and require picture-frame borders to hide the board ends. Installed cost on a 14x20 deck runs $22,800 to $29,500 CAD in 2026.

Ledger board

The horizontal board bolted to a house's rim joist that carries one side of an attached deck's frame, required to be flashed and through-bolted under OBC.

A ledger board is a length of pressure-treated dimensional lumber (typically 2x10 or 2x12) lag-bolted or through-bolted to the rim joist of a house to carry the inside edge of an attached deck frame. Under Ontario Building Code, the ledger must be through-bolted with Simpson SDWS or equivalent structural screws (not nailed), flashed with metal or self-adhering membrane to prevent water intrusion, and separated from the house sheathing by a spacer to allow drainage. A poorly attached ledger is the most common cause of catastrophic deck collapse.

Kitchens

Shaker cabinet

A five-piece flat-panel cabinet door with a square frame and a recessed centre panel, the dominant cabinet style in GTA kitchen renovations for the last decade.

A Shaker cabinet door is constructed as a frame of four stile-and-rail pieces surrounding a flat centre panel, typically MDF or veneered plywood. Named after the Shaker religious community whose plain furniture style inspired it, the design is now the default for mid-tier to high-end kitchen cabinetry in the GTA. It paints cleanly, reads as neither traditional nor aggressively modern, and suits almost any house. Semi-custom Shaker cabinets from a Canadian cabinet shop run $280 to $550 per linear foot of cabinet in 2026.

Semi-custom cabinets

Cabinets built in a shop from a fixed menu of sizes, door styles, and finishes, sized in 3-inch increments and customizable but not one-off.

Semi-custom cabinets are factory or small-shop cabinets offered in a predetermined range of widths (typically 9, 12, 15, 18, 21, 24, 30, 33, 36, 42 inches) and a fixed catalogue of door styles, wood species, and finishes. Unlike stock cabinets (IKEA SEKTION), semi-custom allows choice of soft-close hardware, interior fit-outs, and some dimensional flexibility. Unlike full custom, it does not accommodate arbitrary dimensions or bespoke profiles. Brands in the GTA include Kraftmaid, Fabritec, and Cabico. Pricing runs $280 to $550 per linear foot installed in 2026.

IKEA SEKTION

IKEA's modular kitchen cabinet system, the dominant stock cabinet option in the GTA for budget-conscious renovations.

IKEA SEKTION is IKEA's current-generation kitchen cabinet system, sold as flat-packed melamine-over-particleboard boxes with a 25-year warranty. Boxes come in fixed widths (15, 18, 20, 24, 30, 36 inches). The door panels are a separate purchase, ranging from IKEA's own finishes through third-party replacement doors like Semihandmade and Plykea. SEKTION is the default for DIY-assembled or budget-contracted kitchen renovations in the GTA. Full kitchen installed cost runs $8,000 to $22,000 in 2026, roughly 40 percent of a semi-custom equivalent.

Quartz countertop

An engineered stone countertop made of roughly 93 percent crushed quartz bonded with polymer resin, the dominant kitchen counter material in the GTA.

Quartz countertops (also called engineered stone) are manufactured by combining crushed natural quartz with polymer resins and pigments under pressure. Unlike natural stone they are non-porous, uniform in colour, and require no sealing. Major brands include Caesarstone, Silestone, Cambria, and MSI Q. In the GTA in 2026, installed quartz countertops run $80 to $140 per square foot for mid-tier colours and $140 to $220 for premium patterns. The dominant kitchen counter material in current renovations.

Bathrooms

Curbless shower

A walk-in shower with no raised threshold between the bathroom floor and the shower floor, built on a sloped mud bed and waterproofed with sheet or liquid membrane.

A curbless (or barrier-free, or zero-threshold) shower is built by dropping the subfloor in the shower footprint so the finished shower floor sits flush with the rest of the bathroom floor. A 1/4 inch per foot sloped mortar bed directs water to a linear or point drain. The entire floor and lower walls are waterproofed with a sheet membrane (Schluter Kerdi), a liquid membrane (RedGard), or a traditional hot-mop system. Curbless showers are the standard for aging-in-place renovations because they allow wheelchair and walker access without a threshold trip hazard.

Schluter Kerdi

A polyethylene sheet waterproofing membrane bonded to substrate with unmodified thinset, used to waterproof tiled shower walls and floors.

Schluter Kerdi is a thin (about 0.2 mm) polyethylene sheet with a non-woven fleece backing on both sides. It is bonded to backer board or drywall with unmodified thinset and becomes the waterproof layer behind tile. Kerdi is the standard specification for high-end Ontario bathroom remodels because it is factory-manufactured (uniform thickness), fast to install, and backed by Schluter's warranty when paired with their Kerdi-Drain, Kerdi-Band, and Kerdi-Fix accessories.

RedGard

A liquid-applied waterproofing and crack-isolation membrane rolled onto shower substrates, used as an alternative to sheet membranes like Kerdi.

RedGard is a rubberized acrylic liquid that is rolled or brushed onto cement backer board or drywall in two coats and cures into a pinkish waterproof membrane. It is thicker than Kerdi (about 30 mils cured) but more forgiving of irregular substrate shapes and inside corners. RedGard is common in mid-tier Ontario bathroom remodels and is ANSI A118.10 compliant. It requires 24 hours between coats and 24 hours after the second coat before tiling.

Hot mop

A traditional shower pan waterproofing method using layers of fibreglass felt bedded in hot asphalt, installed by a specialized crew.

Hot mopping is the oldest shower pan waterproofing method still in residential use. A crew heats asphalt in a kettle, then mops it onto the shower pan in alternating layers with fibreglass felt to build a flexible waterproof membrane. Hot mop is the cheapest method at roughly half the cost of Kerdi for a full shower, but it requires a dedicated crew, a 48-hour cure, and smells terrible during install. It is still common in budget bathroom renovations and in jurisdictions where hot mop is the local default.

Mud bed

A dry-pack mortar floor poured and sloped toward a drain, used as the substrate for tile in a shower or wet room.

A mud bed (or mortar bed) is a mixture of portland cement, sand, and just enough water to hold shape (dry-pack), troweled into a shower footprint and sloped at a minimum of 1/4 inch per foot toward the drain. The mud bed is the structural slope that carries water to the drain; the waterproofing membrane sits on top. Mud beds are required under most sheet membrane systems and are the craft skill that separates a good shower install from a bad one.

Finish Carpentry

Scribing

A technique for trimming a board so its edge mirrors an irregular surface, used in finish carpentry when floors, walls, or ceilings are out of square.

Scribing is the carpentry technique of marking a board with a compass so that when cut, the board's edge follows the irregular profile of an adjacent surface. It is essential in old houses where floors slope, walls wave, and ceilings sag. A scribed baseboard sits flush to an uneven floor without a gap. A scribed cabinet side fits tight to a wavy wall. The tools are simple — a drafting compass, a jigsaw, a block plane, sandpaper — but the skill takes years to develop. Scribing is the difference between finish carpentry that looks inevitable and finish carpentry that looks caulked.

MDF (medium-density fibreboard)

A paint-grade sheet material made of wood fibres compressed with resin, used for baseboards, casing, and cabinet parts where a smooth paint finish is the goal.

Medium-density fibreboard is a manufactured panel made from wood fibres bonded with urea-formaldehyde resin and pressed into sheets of uniform density. MDF has no grain, sands and machines cleanly, and takes paint better than any natural wood. It is the default material for paint-grade interior trim in the GTA because it is dimensionally stable in indoor climate-controlled environments and does not have the knots, grain raise, or warping of solid poplar or pine. MDF is unsuitable for bathrooms or basements with humidity unless sealed aggressively.

Poplar

A light, fine-grained hardwood used as a paint-grade alternative to MDF for baseboards, casing, crown molding, and cabinet face frames.

Poplar (Liriodendron tulipifera, technically a tulip tree) is a soft hardwood with a pale green-to-yellow colour and a fine, straight grain. It is cheap relative to other hardwoods, machines cleanly, takes paint well, and is dimensionally stable in a conditioned interior. Poplar is the preferred paint-grade solid-wood trim material in Ontario for rooms where MDF is inadequate — bathrooms, mudrooms, or any location where physical impact is likely. Clear poplar runs $4 to $6 per linear foot for 1x4 at a proper lumberyard in 2026.

Built-in

A piece of permanent cabinetry or shelving designed and installed to fit a specific architectural space, not movable like a freestanding piece of furniture.

A built-in is custom millwork — a library wall, a mudroom bench, a window seat, a fireplace surround, a desk nook — that is designed and scribed to fit a specific wall, alcove, or architectural feature in a house. Built-ins are distinct from freestanding furniture because they are nailed, screwed, or anchored to the house structure and cannot be moved. They are one of the highest-skill finish carpentry categories because every piece is unique to the room, and they cost $400 to $1,200 per linear foot in the GTA in 2026 depending on material and complexity.

Related: custom built ins cost gta 2026

Crown molding

Decorative trim installed at the junction of wall and ceiling, mitered and caulked to create a clean architectural line.

Crown molding is a profiled trim piece installed at the wall-ceiling junction. In paint-grade residential work it is typically 4 to 7 inches tall, in MDF or poplar, coped at inside corners and mitered at outside corners. Properly installed crown sits on a tapered spring angle (usually 38 or 45 degrees), is nailed through its top and bottom edges into studs and top plates, and is caulked tight at both edges before painting. Crown molding in a 12x15 room runs $650 to $1,200 installed in the GTA in 2026.

Roofing

Asphalt shingle

The dominant residential roofing material in Ontario, made of a fibreglass mat coated in asphalt and mineral granules, installed in overlapping courses.

Asphalt shingles are flat rectangular roofing pieces consisting of a fibreglass mat saturated with asphalt and topped with coloured mineral granules. Architectural (laminated) shingles are the current standard, with two layers bonded for dimensional appearance and improved wind resistance. The dominant brand in Ontario is GAF Timberline HDZ. Installed lifespan on a typical GTA roof is 20 to 25 years. Installed cost in 2026 on a 2,000 sq ft single-family roof runs $8,500 to $14,000 CAD.

Standing-seam metal roof

A metal roof system with vertical panels joined by raised seams that snap or crimp together, offering 40-60 year lifespans and exceptional weather resistance.

A standing-seam metal roof consists of vertical metal panels (typically 16 to 18 inches wide) with raised interlocking seams at each edge, either snap-lock or mechanically crimped. The fasteners are hidden beneath the seams, so no exposed screw penetrations exist. Panels are typically 24-gauge galvalume steel with a Kynar paint finish, and commonly come in slate grey, black, and copper tones. Lifespans of 40 to 60 years are realistic with proper install. Installed cost in 2026 on a GTA single-family home runs $22,000 to $38,000 CAD.

Cedar shake roof

A traditional wood roof made of hand-split or sawn western red cedar shingles, favoured on heritage and custom homes in Ontario.

Cedar shake is western red cedar split or sawn into roofing shingles, installed in overlapping courses over spaced sheathing to allow airflow. Shakes are thicker and rougher than shingles (which are sawn smooth on both faces). Cedar roofs last 25 to 35 years in Ontario climate, require occasional cleaning of organic growth, and cost $35,000 to $60,000 installed on a typical GTA single-family home in 2026. Fire-treated cedar (Class C rated) is required by some insurance carriers.

Ice and water shield

A self-adhering rubberized membrane installed under shingles at eaves, valleys, and penetrations to prevent leaks from ice dams and wind-driven rain.

Ice and water shield (the generic term; the dominant brand is Grace Ice & Water Shield) is a self-adhering waterproofing membrane installed on the roof deck before shingles are laid. In Ontario it is required by OBC at all eaves from the edge up to 36 inches inside the exterior wall line, in all valleys, around all penetrations, and on low-slope sections. The membrane self-seals around nail penetrations, stopping leaks from ice-dam backup and wind-driven rain that gets under the shingles.

Flashing

Pre-formed metal or rubber pieces installed at roof penetrations, edges, and junctions to direct water away from the building envelope.

Flashing is the sheet-metal, rubber, or composite material installed at every place a roof meets another surface: chimneys, walls, valleys, vent pipes, skylights, and eaves. Flashing is lapped with the surrounding roofing material so water flows down and out, never behind. Galvanized steel, aluminum, and copper are common materials. Flashing is the highest-failure point on a residential roof — a failed flashing is responsible for most interior water damage from an otherwise-intact roof.

Soffit and fascia

The underside (soffit) and vertical edge (fascia) of a roof overhang, which together ventilate the attic and provide a finished edge for the gutters.

The soffit is the horizontal underside of a roof overhang (the part you see when you stand beneath the eaves). The fascia is the vertical board at the edge of the overhang that the gutter attaches to. Soffits must be ventilated (perforated aluminum is the default) so air can enter the attic and balance the ridge vent exhaust. Damaged soffit and fascia are common on older GTA homes and are usually replaced during a roof project because they are accessible with the same scaffolding.

Drone roof survey

A post-storm roof inspection using an unmanned aerial vehicle to photograph and document shingle damage for insurance claim purposes.

A drone roof survey uses a consumer-grade UAV (typically a DJI Mavic or similar) to photograph a roof from multiple angles after a storm event, producing high-resolution image sets that document hail, wind, or debris damage to shingles, flashing, and soffit. The survey report is submitted to the homeowner's insurance carrier as part of a damage claim. Drone surveys avoid the liability of a ladder inspection, can photograph steep or multi-storey roofs that are unsafe to walk, and produce time-stamped GPS-tagged evidence that carriers accept.

Residential carpentry glossary.