A home addition or second storey is the biggest structural change most homeowners will ever make to a property. It's different from a kitchen or basement remodel because it touches the building envelope, the foundation or roof structure, and often the permit process with the City of Markham. Whether you're adding a ground-floor extension for a bigger kitchen and family room, or lifting the roof to add bedrooms above an existing bungalow-style home, the work involves structural engineering, new footings or reinforced framing, and coordination between a general contractor, an architect or designer, and trades for electrical, plumbing, HVAC, and insulation.
We've looked at 6 companies in this category that handle additions and second-storey builds in Markham. Some specialize in full design-build packages, others focus on the construction side and work alongside your own architect.
Ask to see a portfolio of completed additions, not just kitchens or bathrooms, since structural work carries different risks. Confirm the company pulls permits under its own name and carries WSIB coverage and liability insurance. A serious contractor will walk you through how they plan for unexpected findings, like an undersized foundation or old wiring, before work starts, and will put a change-order process in writing rather than handling surprises verbally.
Our rankings weigh verified reviews, licensing and insurance status, how long a company has operated in the Markham area, and the consistency of project types they handle. See the full breakdown of criteria on our methodology page, and check the ranked guide to renovation contractors in Markham for how these 6 firms compare against the wider field.
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6 businesses, scored on recent reviews. The order weighs each business's overall score by how much of its reviewed work is home additions & second storeys, so a lower-scored specialist can rank above a higher-scored generalist.
Reno Compass delivers consistent, high-quality renovations with strong project oversight and transparent communication. Reviewers consistently praise on-time completion, budget honesty, and Vincent's team's ability to guide clients through complex decisions while maintaining respect for living spaces during construction.
Reviewers consistently praise JY Construction for professionalism, responsiveness, and skilled execution across residential and commercial work. The owner and team are described as patient, detail-oriented, and genuinely invested in solving problems rather than rushing jobs.
Most customers praise TROC for finishing on time and budget with skilled trades and daily site updates. Project managers William, Jeff, and Cesar earned particular respect for staying accessible and solving problems within hours. One significant dispute involved an 8-month basement and bathroom job that ran triple the quote, with structural mistakes, poor material handling, and subcontractor payment failures requiring a second contractor to redo work.
Every reviewer reports smooth, professional experiences with finished work exceeding expectations. Owners Summer and Arno, along with crew lead Lao Liu, earn consistent praise for responsiveness, guiding homeowners through choices with patience, and delivering projects on schedule. Basement and bathroom work stands out for precision and modern finishes; one client reported the team returned six years later to fix a toilet without hesitation. Clean worksites and willingness to address concerns immediately shape the overall picture of reliability and care. Reviewers cite kitchen, bathroom, basement, and whole-house work, with flooring and structural repairs (load-bearing walls, popcorn removal, uneven floors made level) all executed to high standards. The team holds WSIB coverage and $5 million commercial insurance; their website lists unfinished basement renovation at $44.99 per sqft. No negative feedback appears across 79 five-star reviews.
Staff respond rapidly to water damage emergencies and manage the full restoration process with precision, often working around insurance delays. Named team members like Ismael, Araceli, Hasan, Alvin, and Barish deliver consistently polished finishes on drywall, baseboards, ceilings, and damaged areas, leaving spaces clean and structured condo projects with calm professionalism.
Get matched with home additions & second storeys in Markham
No cost, no obligation. Tell us about your project and we'll connect you with contractors who fit your needs.
X&H's basement-to-kitchen scope draws repeat customers and insurance-referred work. Daniel and his team consistently finish on schedule, charge transparently for scope changes, and stand out for detail work in bathrooms and kitchens. The design department (Monica, Claire, Lee, Jacqueline) guides fixture and layout choices. Staff like Marc (site supervisor) maintain clean worksites and resolve issues quickly. Warranty follow-up years later impressed at least one homeowner. The main trade-off is higher pricing; one designer transition mid-project caused temporary friction but didn't spoil the result.
Enquiries from our contact forms may go to partner providers who can do the work, and we may receive a referral fee. Our rankings are based on our published scoring method only and are never affected by referral fees.
Last updated 2026-08-08