Basement Renovation in Markham: What Eight Real Projects Cost (2026)

Every basement we build is priced from the same quote sheet, line by line, and a standard 1,000 square foot basement with a three-piece bathroom comes to about $67,800 before HST. In Markham, the eight basements we have quoted and built since 2021 ran from $40,000 to $50,000 for a 550 to 770 square foot finish with a bathroom, up to $170,000 to $180,000 for an 832 square foot rebuild that also reached up into the main floor. The City charges $8.43 per square metre for a residential alteration permit in 2026, which is about $785 on a 1,000 square foot basement. The Markham page has the short version. This one is built from real quotes on eight Markham streets. Run your own square footage through the basement cost calculator to see where a project like yours starts.

What eight Markham basements actually cost

The three cheapest projects on the list are all from 2021, and all three had a full bathroom. Scott Brown Street was 553 square feet with a three-piece bathroom, a custom tiled shower, new oak stairs with iron spindles and 18 pot lights, scheduled at 35 days. Dungannon Drive was 668 square feet with the same bathroom package, a 60-inch linear fireplace and 25 pot lights over 48 days. Boswell Road was 768 square feet with a tiled shower, a new laundry rough-in, soundproofing, a DRICORE subfloor and 30 pot lights over 37 days. All three priced at $40,000 to $50,000. Those are 2021 numbers, so read them as a floor, not a target.

The middle of the list is where most Markham families land now. John Anthony Drive in 2024 was 1,200 square feet with a bedroom, a three-piece bathroom with a tiled shower, a DRICORE subfloor and 25 pot lights, at $80,000 to $90,000 over 60 days. The one unusual line was the walls: the owner replaced the builder's batt insulation with R22 spray foam, a $9,000 item on its own. Morning Dove Drive in 2025 was only 819 square feet but landed in the same $80,000 to $90,000 band over 90 days, because the money went into millwork: 15 feet of lower cabinetry under the TV, a 12-foot fluted slat feature and an arched niche.

Then the price starts following the cabinetry rather than the floor area. Donald Cousens Parkway in 2023 was 585 square feet, yet it came to $80,000 to $90,000 over 75 days, with a built-in TV wall, a built-in gym wall with a mirror nearly eight feet wide, a wine storage wall, three pocket doors and a tiled shower. Crescent Park Lane in 2024 went the other way: 1,640 square feet with no bathroom at all, priced at $110,000 to $120,000 over 75 days, with a veneer custom bar, a six-foot island with a double waterfall quartz top, a 19-foot TV wall, a 74-inch linear fireplace and 58 pot lights.

The largest number on the list needs an explanation. Sherwood Forest Drive in 2025 was 832 square feet at $170,000 to $180,000. It started with demolishing an existing finished basement, then added an 11-foot L-shaped bar, a larger bathroom with a tiled shower, a 42-inch linear fireplace inside a 13-foot built-in, sauna wiring, a new subpanel and 42 pot lights. It also included new oak stairs on the main level and a second bar built to match the main kitchen, so the headline number is not a basement-only number.

The pattern in the numbers

Put the eight side by side and the curve is familiar. A clean finish with a bathroom, at today's prices, sits around $70 per square foot, which is where John Anthony Drive lands. Add cabinetry, an island or a wine wall and the same footage moves past $100 per square foot, which is Morning Dove Drive at roughly $106 and Donald Cousens Parkway at about $147. Our GTA basement cost guide shows the same curve across 400+ projects.

Crescent Park Lane surprises people. At roughly $68 per square foot it is the cheapest square foot on the list after the 2021 jobs, despite the bar and the 19-foot TV wall, because it has no bathroom and 1,640 square feet spreads the fixed costs thin. The permit, the bin, the stairs and the bathroom cost the same in a small basement as in a big one, which is why Donald Cousens Parkway works out to more than double the per-foot price. A three-piece bathroom starts at about $11,700 on our quote sheet and climbs past $20,000 with a custom tiled shower, a bench and a niche. Our basement bathroom plumbing guide explains why the drain decides that number before the tile does.

The Markham building permit, in real numbers

The City of Markham requires a building permit before any renovation project, and its own list of examples includes constructing separate rooms in a basement, renovating a dwelling to provide a full basement, installing a basement entrance and installing an accessory apartment. Interior damp-proofing of a basement is on the list of work that does not need one. Under the fee schedule for applications submitted after December 31, 2025, residential alterations are charged at $8.43 per square metre, with a minimum fee of $151. A 1,000 square foot basement is about 93 square metres, so roughly $785. John Anthony Drive at 1,200 square feet is about 111 square metres, or roughly $940. A secondary suite is charged at $22.08 per square metre instead, which is why the decision between a rec room and a rental unit has to be made before the drawings start. Our GTA permit guide compares the fees town by town.

Markham takes every application through its ePLAN portal, and a non-refundable $100 pre-application fee has to be paid before drawings can be uploaded. The City's target for the first review of a house project is 10 business days for a complete application and 20 for an incomplete one, which is the strongest argument for getting the drawings right the first time. We price the permit package as its own line and handle the application, and the contract spells out how permit inspections affect the completion date.

What Markham houses have in common

None of the eight needed underpinning or digging for ceiling height, and seven kept the builder's wall insulation. John Anthony Drive was the exception, and our basement insulation guide explains when that trade is worth it. The recurring extra in Markham is heat: on six of the eight quotes we modified or dropped the heat registers to the floor. Builders leave them high in the joists because nobody lives down there yet. Once you finish the room, you want the warm air at your feet.

How to read your own Markham quote

Three questions sort most quotes. Is there a bathroom, and is the shower tiled or prefabricated? Is there cabinetry, and is it a bar with stone or a run of lower cabinets? And is the price line by line? Our quotes are itemized and locked, which is why we can publish the numbers above. If a number on your quote does not have a line, ask for one. If you want to spread the cost, we also have a financing option.

FAQ

How much does a basement renovation cost in Markham?

From our own quotes, a finished basement with a three-piece bathroom in Markham runs from about $40,000 to $50,000 for 550 to 770 square feet at 2021 prices, to $80,000 to $90,000 for 800 to 1,200 square feet in 2024 and 2025. Bars, islands and built-ins push the same footage past $110,000. All figures are before HST.

Do I need a building permit to finish a basement in Markham?

Yes. The City of Markham requires a permit before any renovation project and lists constructing separate rooms in a basement as an example. Residential alterations are charged at $8.43 per square metre under the 2026 fee schedule, with a $151 minimum, plus a $100 pre-application fee on ePLAN.

How long does a Markham basement renovation take?

Seven of the eight projects above carried a guaranteed construction time, and those ran between 35 and 90 days. Simple finishes with a bathroom ran 35 to 60 days; projects with bars, built-ins and feature walls ran 75 to 90 days.

Why does a small basement cost more per square foot?

The permit, the bin, the stairs and the bathroom cost the same regardless of room size. Donald Cousens Parkway, at 585 square feet with a full bathroom and built-ins, worked out to about $147 per square foot, while Crescent Park Lane, at 1,640 square feet with no bathroom, was about $68.

If you are planning a basement in Markham, book a free in-home consultation and we will measure the space, draw it in 3D at no charge, and hand you a quote you can compare line by line against anyone else's. The numbers above are real because the quotes behind them are, and yours will be too.