Sample quote Additions

Single-storey rear addition, Kanata

A single-storey family room added across the back of a two-storey home, with large windows and patio doors.

The back of a two-storey brick house with a single-storey addition that has large windows and patio doors facing the lawn — Illustration only; the quote prices the work listed, not everything shown in the picture.

The brief

A two-storey house with a small back yard and a cramped main floor. The owners want a family room across the back of the house, opened to the kitchen, with large windows and a patio door onto the lawn.

Priced as: Rear or side addition, one storey, 400 sq ft, mid-range finishes, suburban Ottawa.

What it assumes

Mid-range. Brick or fibre-cement cladding matched to the house, quality windows and a designed interior.
Rear or side addition, one storey. New rooms on a new foundation.
Included. Drawings, engineering and the permit application; Foundation, framing, roof, windows and cladding; Heating, plumbing and electrical extended from the house; Insulation, drywall, flooring, trim and paint; Permit fees and inspections.
Not included. Landscaping and restoring the yard; Furniture, appliances and decor; Development charges, if the City applies any; Surprises in the existing house once the wall is opened.
Prices. Based on published Ottawa and Ontario price guides, checked October 2026, and before HST unless a line says otherwise. They are estimates, not an offer. A firm written quote follows a site visit.

Task by task

Each task with its price and the stage of the job it belongs to. We book the right trade for each one.

Tasks and prices: Rear or side addition, one storey, 400 sq ft, mid-range finishes, suburban Ottawa
Task	Plan	Demo	Rough-in	Close-in	Finish	Price
Drawings, engineering and permit applicationArchitectural drawings, structural engineering and the permit package.Plan	Plan					$9,700
Site work and foundationExcavation, footings, foundation walls, slab and waterproofing.Demo to Rough		Demo	Rough-in			$21,500
Framing: floor, walls and roofFloor system, walls, roof trusses and sheathing.Rough			Rough-in			$18,500
Roofing, windows, doors and claddingShingles, windows, exterior doors, siding or brick, soffit and fascia.Rough to Close			Rough-in	Close-in		$16,900
Heating, cooling and plumbing extensionDucts and returns from the existing system, plumbing where needed.Rough			Rough-in			$7,500
Electrical and lightingCircuits, outlets, lights and switches, with inspection.Rough, Finish			Rough-in		Finish	$6,100
Insulation and air sealingSpray foam or batt insulation, vapour control and air sealing.Close				Close-in		$3,900
Drywall, taping and paintBoard, tape and mud, prime and paint.Close to Finish				Close-in	Finish	$6,900
FlooringSubfloor, underlay and flooring.Finish					Finish	$5,400
Interior doors, trim and stairsDoors, baseboard, casing and stair work.Finish					Finish	$6,400
Tie-in to the existing houseOpen the existing wall, support it, and blend the old and new finishes.Demo to Close		Demo	Rough-in	Close-in		$5,600
Extra windows and patio doorsSupply and install, with trim and finishing.Rough to Close			Rough-in	Close-in		$5,700
Project management, supervision and site costsScheduling and supervising each task, bin rental, site protection, insurance and final cleaning.Plan to Finish	Plan	Demo	Rough-in	Close-in	Finish	$11,400
Permits and inspectionsBuilding and electrical permit fees and inspections, as the work requires them.Plan	Plan					$3,600
Subtotal before HST						$129,100
HST (13%)						$16,783
Estimated total with HST						$145,883

Prices are estimates based on published Ottawa and Ontario price guides, checked October 2026. They are not an offer. A firm written quote follows a site visit.

What would change the price

The same job with one thing changed. Choose a row to open that version in the estimator.

How the total changes with one change to this sample quote
Change	Difference	New total
Premium finishes	+$36,160	$182,043
Add a bathroom in the addition	+$28,137	$174,020
Dig a full-height basement under it	+$30,849	$176,732
Make it 100 sq ft larger	+$23,730	$169,613

More sample quotes

A renovated kitchen with white cabinets, a navy island with a white counter, wood floors and an arched opening to the dining room

Kitchens The Glebe

Kitchen opened to the dining room

Likely range, with HST $60,700 to $81,400 about $431 per sq ft

A closed-in kitchen in an older brick home opened to the dining room, with an island, new lighting and a standard appliance package.

A renovated ensuite with a glass walk-in shower, a floating wood vanity, a round mirror and a warm tile floor

Bathrooms Westboro

Ensuite with a walk-in shower

Likely range, with HST $31,400 to $42,000 about $475 per sq ft

A tub-and-tile ensuite rebuilt with a walk-in glass shower, a floating vanity, a heated floor and a proper exhaust fan.

A finished basement family room with an open wood staircase, built-in shelving around a television, a grey sectional sofa and a bar nook

Basements Barrhaven

Basement family room with a bathroom

Likely range, with HST $89,600 to $120,100 about $127 per sq ft

An unfinished basement finished as a family room with built-in shelving, a three-piece bathroom and a new egress window.