Basement Finishing and Renovation
Turn the floor you rarely use into the space you need: a family room, an office, a guest suite or a legal second unit.
Basement Finishing and Renovation in Toronto and across Ontario
A basement is the largest unfinished space in most Ontario homes, and the most technical one to finish well. Moisture, insulation, ceiling height, exits, ducts and drains all have to be solved before the finishes go in, or the new space will not last.
Harborline Sterling handles the whole job: checking for moisture and fixing it first, framing and insulating to the Ontario Building Code, adding bathrooms, bedrooms, kitchens or a separate entrance, and managing the permits and inspections. If you are planning a rental or in-law suite, we design it as a legal second unit from the start.
Harborline Sterling Construction Inc. is principal-led. One of our co-founders, Mansoor Alam Khan or Maqsood Mohammed, oversees every project, so decisions get made quickly and you always know who is accountable.
What basement finishing and renovation includes
Every project is different, but these are the parts of the work we take responsibility for.
Moisture check and waterproofing
We look for signs of water, test problem areas and fix the cause first, whether that means sealing foundation cracks, improving grading, adding a sump pump or installing a backwater valve.
Layout and design
Family rooms, bedrooms, offices, gyms, home theatres, laundry and storage, planned around the furnace, ducts, posts and beams you have to work with.
Bathrooms and wet bars
New bathrooms, wet bars and kitchenettes, with plumbing, venting and drain connections done by licensed plumbers under permit.
Legal second units
Basement apartments designed for Ontario's rules on additional residential units: fire separations, smoke and carbon monoxide alarms, safe exits, separate entrances and the permits that make the unit legal.
Separate entrances and egress windows
Walk-out or below-grade entrances and enlarged bedroom windows that meet Building Code exit requirements, with the excavation, structure and drainage they need.
How the work runs
The same disciplined backbone we use on every project, adapted for this kind of work.
Assess
Site visit, moisture check and a look at structure, ducts, plumbing and ceiling height.
Design and permit
Layout, drawings and a fixed-scope proposal, then the building permit where one is needed.
Build
Framing, insulation, rough-ins, inspections, drywall and finishes, with the rest of your home protected from dust.
Hand over
Final inspection, deficiency walk-through and warranty documents.
Often paired with basement finishing and renovation
Many home projects combine services. One contract can cover all of it.
Foundations, Waterproofing and Concrete
Foundation repair, basement waterproofing, underpinning, sump pumps, backwater valves and concrete work.
Learn moreBathroom Renovations
Full bathroom remodels, ensuites, powder rooms and curbless showers, built to stay dry for decades.
Learn moreHome and Room Renovations
Whole-home renovations or a single room, done properly: layouts, floors, walls, stairs, lighting and finishes.
Learn moreWhy choose us for basements
From the first visit to the final walk-through, here is what you can count on.
One accountable team
One contract and one point of contact for design, permits, trades and inspections, so you are never left coordinating contractors yourself.
Principal-led
A founding principal oversees your project and is a phone call away, from the first visit to the final walk-through.
Licensed trades
Electrical work by licensed electrical contractors, gas work by TSSA-registered contractors and plumbing by licensed plumbers, with permits and inspections where required.
Other ways we can help
Many projects combine services. Ask us how they fit together for yours.
Also from Harborline Sterling
Related reading
BasementsAdding a Legal Basement Apartment in Ontario: What Homeowners Need to Know
Zoning, permits, fire safety and the steps that turn a basement into a legal second unit.
Read article
Home renovationPlanning a Home Renovation in Ontario: Permits, Contracts and Budgets
Permits, licensed trades, written contracts, holdback and budgets: what to sort out before your renovation starts.
Read articleFrequently asked questions
Do I need a permit to finish my basement?
Often, yes. In Toronto, for example, a permit is needed when finishing a basement involves structural changes, new plumbing or heating, underpinning, a new entrance or a second unit. A basic finish with none of those may not need one. We confirm the rules with your municipality before work starts.
Can I turn my basement into a legal rental unit?
In most Ontario municipalities, yes. Provincial rules allow up to two additional residential units on most lots with a detached house, semi-detached house or townhouse. The unit needs a building permit and must meet Building Code and Fire Code requirements, and some municipalities also require registration.
How long does a basement finish take?
A straightforward finish usually takes several weeks of construction once permits are in hand. Bathrooms, second units, underpinning or new entrances add time. We give you a schedule with the proposal.
What can be done about a low ceiling?
We measure early. Options include reworking ducts and beams, or lowering the floor by underpinning or benching, which needs a structural engineer and a permit. We will tell you plainly whether the cost makes sense for your plans.
Do moisture problems need fixing first?
Yes. Finishing over a damp basement traps moisture behind new walls. We find and fix the cause before insulation and drywall go in.
Can you add a separate entrance?
Yes. A new basement entrance usually needs excavation, a retaining structure, drainage and a building permit. We design and build it as part of the project.
Plan your basement with us
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.