Basement Renovation in Markham
Markham’s detached homes have some of the largest basements in the GTA — and many of them are still unfinished or barely used. A basement renovation turns that space into a legal second suite, a home office, an in-law suite, a family room or a gym, adding real living space without an addition.
SM Builders renovates basements across Markham, from Unionville and Thornhill to Cornell and Milliken. We handle permits, waterproofing, framing, electrical, plumbing and finishing, with a written quote agreed before work starts.
About Services
Our Basement Renovation Services in Markham
The most popular basement projects in Markham include:
- Legal second suites and basement apartments for rental income
- In-law and nanny suites with kitchenette and bathroom
- Home offices and remote-work studios
- Family rooms, home theatres and gyms
- Basement bathrooms, laundry rooms and wet bars
- Full basement finishing from unfinished concrete to move-in ready
Renovating Basements in Markham: Suites, Permits and Value
Markham’s high home prices make legal basement suites especially attractive: a well-built suite can generate rental income that meaningfully offsets a mortgage. But a suite is only valuable if it is legal — it needs proper ceiling height, egress windows, fire separation, a separate entrance and a City of Markham second-unit permit. We build to code and handle the permit process, so your suite is insurable and sellable.
If rental is not the goal, the best return comes from space your family will actually use daily: a home office with proper lighting and sound control, or a family room that takes pressure off the main floor. In Thornhill and Unionville’s older homes, we also check for moisture and foundation issues first — finishing over a damp wall is money wasted, so waterproofing and drainage come before drywall.
Our Renovation Process
How Much Does a Basement Renovation Cost in Markham?
Typical ranges: basic finishing $30,000 to $50,000, a comfortable family-space finish $50,000 to $75,000, and a legal second suite $75,000 to $120,000+, depending on size, bathroom and kitchenette, and permit requirements. See our basement finishing cost guide and basement renovation cost guide for detailed breakdowns, then get your exact price from a free estimate.
Why Homeowners in Markham Choose SM Builders
We inspect before we quote, we build to code, and we do not cut corners on waterproofing or fire separation. Our main basement renovation service covers our approach, and our basement apartment guide explains legal suites in more detail.
Frequently Asked Questions
In most cases, yes, if the basement meets ceiling-height, egress, fire-separation and parking rules. We assess your basement during the free consultation and handle the permit application.
Basic finishing takes 6 to 10 weeks. Legal suites take 8 to 12 weeks including inspections.
Yes, but waterproofing comes first. We identify the moisture source, fix drainage or sealing, and only then finish. Finishing over damp walls causes mould and wasted money.
Yes — Unionville, Thornhill, Milliken, Cornell, Angus Glen, Greensborough, Box Grove and surrounding areas.
Find out what your basement can become. Call +1 647-331-7366 or request a free estimate and we will inspect your basement and give you a clear written quote.