General Contractor in Markham
Markham is one of the GTA's strongest commercial and technology markets, with major office parks, a growing downtown, busy retail and restaurant corridors, and fast-growing neighbourhoods.
Your construction partner in Markham
Harborline Sterling Construction Inc. is a Toronto-based general contractor serving homeowners, businesses and public owners in Markham. We renovate homes, build and fit out commercial space, and deliver paving, sidewalks, lighting and park projects, with one point of responsibility from permits to keys.
Every project is overseen by one of our founding principals, Mansoor Alam Khan or Maqsood Mohammed.
Construction services in Markham
Three divisions, one accountable team.
Commercial
New buildings, renovations, tenant build-outs, design-build and construction management for businesses, landlords and developers.
- New Construction
- Remodeling and Additions
- Project Management
- Construction Management
- Tenant and Office Build-Outs
- Design-Build
- Maintenance and Small Works
Residential
Basements, kitchens, bathrooms, additions, driveways, decks and full-home renovations, from one room to the whole house.
- Basements
- Bathrooms
- Kitchens
- Home and Room Renovations
- Additions
- Driveways and Interlock
- Decks, Fences and Outdoor Living
- Roofing, Siding and Windows
- Foundations and Waterproofing
- Accessible Renovations
Infrastructure and Public Works
Roads, sidewalks, street lighting, parks and underground services for municipalities, public agencies, developers and property managers.
- Roads and Paving
- Sidewalks and Curbs
- Street and Site Lighting
- Parks and Playgrounds
- Sewers and Watermains
- Demolition and Site Preparation
Building in Markham: what to know
Permits and approvals
Building permits are issued by the City of Markham's Building Standards department, and site plan approval runs through the city's planning department. York Region controls regional roads and much of the major water and wastewater infrastructure, so projects with new access points or servicing connections may need regional approvals as well.
Site conditions and logistics
Newer business parks and subdivisions generally have good servicing, but stormwater management and site plan conditions can be detailed. Sites near the Rouge River and its tributaries may fall within Toronto and Region Conservation Authority regulated areas.
Ontario Building Code
The 2024 Ontario Building Code took effect on January 1, 2025. We work with your designers to make sure drawings, barrier-free design and life-safety systems meet the current Code.
Winter construction
Frost, cold-weather concrete, temporary heat and shorter days affect cost and schedule. We plan for the season from the start, so winter never becomes a surprise.
Where we work in Markham
Highway 404 and 407 corridor
Offices, technology campuses, light industrial and flex space.
Downtown Markham and Markham Centre
Mixed-use, retail and office work in a planned, transit-oriented district.
Unionville, Cornell and Markham neighbourhoods
Basements, kitchens, bathrooms, additions and outdoor living projects.
Why clients choose Harborline Sterling
Construction has enough variables without a contractor who goes quiet. Here is how we take them off your plate.
One accountable team
One contract, one point of contact, one builder responsible for the schedule, the budget and every inspection in between.
Principal-led
One of our founding principals oversees every project, so you get senior judgment, quick decisions and a direct line to the people accountable for the result.
Responsive
Calls returned promptly, questions answered the same day where possible, and problems raised early, while they are still cheap to fix.
Frequently asked questions
Who issues building permits in Markham?
The City of Markham's Building Standards department. Regional approvals from York Region may also apply for road access and servicing.
Do you build in Markham's business parks?
Yes. We build and renovate office, flex and light industrial space, including tenant build-outs in multi-tenant buildings.
Do you renovate homes in Markham?
Yes. We finish basements, renovate kitchens and bathrooms, and build additions across Markham, with permits handled through the City of Markham.
Can you build while my business stays open?
Yes. We phase work, control dust and noise, schedule disruptive tasks after hours where needed, and keep your staff and neighbouring tenants informed.
What kinds of projects do you take on in Markham?
Commercial construction and build-outs, home renovations, basements, additions and outdoor projects, and infrastructure work such as paving, sidewalks, lighting and parks.
Start your project in Markham
Put one accountable team in charge: on schedule, on budget, with permits and inspections handled the whole way.
Start your project
Tell us what you are planning. We will set up a straightforward conversation about scope, budget and timeline, with no obligation.