Turn Your Basement into a Rental Income Suite
Building Legal Basement Apartments in Mississauga & the GTA
We build legal basement apartments for use as a rental, guest space, or private living area. We handle the construction, required upgrades, and second unit registration, all under one team, starting with a property assessment so you know what can be built before you commit.
- Tarion Registered
- HCRA Licensed
- Fully Insured
What Makes a Basement Suitable for a Legal Apartment?
Not every finished basement can become a legal basement apartment. We assess the layout, access, ceiling height, services, and structural conditions to determine whether the space can support a separate dwelling.
We identify any changes needed for compliance, including a separate entrance, fire separation, egress, or floor lowering. The completed unit must meet the applicable requirements and be registered with the municipality as a second unit.
Legal Requirements of Building a Basement Apartment on Your Property
A basement must meet specific construction, safety, and municipal standards before it can qualify as a legally registered secondary unit.
Separate Entrance
A dedicated entrance provides independent access to the apartment. Depending on the property, this may involve a walkout or side entrance that meets egress requirements.
Fire Separation
The main home and basement unit require proper fire separation. This includes the assemblies between the spaces and the required alarm systems and detailing.
Ceiling Height
Existing basements do not always have enough height for the intended use. When the existing floor sits too high, GrandBuild can assess whether underpinning or lowering the slab is appropriate.
Light and Ventilation
A habitable basement needs suitable natural light and ventilation. Window sizes and mechanical ventilation form part of the planning.
Plumbing, Electrical and Heating
A self-contained unit needs properly planned services. This can include heating, electrical work, plumbing, a bathroom, and a second kitchen.
Municipal Registration
Construction alone does not make the apartment legal. The completed unit also needs to be registered with the municipality as a second unit.
GrandBuild manages this part of the process so the finished suite is properly recognized.
How We Build and Register Your Basement Suite
Our company manages the work from the initial assessment through construction and registration.
Assess the Existing Basement
We review the basement, property access, servicing, and other site conditions, including ceiling height, walkout access, and underpinning needs, that can affect the project.
Determine What the Property Can Support
We identify whether the basement can accommodate a legal unit and whether options such as a walkout or lowered floor should be considered.
Plan the Required Construction
The scope is developed around the entrance, fire separation, ceiling height, ventilation, services, kitchen, bathroom, and other requirements.
Complete the Build
GrandBuild coordinates the construction and finishing work needed to create the planned basement apartment.
Complete Second Unit Registration
Once the required work is completed, we take the suite through the municipal registration process.
The result is a basement that has been built and registered for its intended use.
What Does a Legal Basement Apartment Cost?
The cost of a legal basement apartment depends more on your property's existing conditions than on the finishes you choose. Three factors have the biggest effect on price:
- Whether the lot can support a walkout
- Whether the existing ceiling height requires underpinning or slab lowering
- How much new plumbing, electrical, heating, and other servicing the unit needs
GrandBuild identifies these conditions during the first property visit. Once the scope of work is clear, we provide a fixed, itemized price, giving you a clear understanding of the full project before construction begins.
GrandBuild Homes Designs Basements Around Your Needs
GrandBuild does more than build rental suites. We create finished lower levels that add genuine living space, whether that's a home gym, private theatre, guest suite, wine room, in-law suite, or extra family living area, designed around how you intend to use it.
Every project meets the same construction standard, with layout and finishes tailored to your goals rather than a fixed template. If a rental isn't part of your plans, GrandBuild creates a lower level that functions as a natural extension of your home instead.
Reach GrandBuild Homes
Call us during business hours or send your project details any time — we build across the GTA, wherever your lot is.
- Monday 9:00 AM – 5:00 PM
- Tuesday 9:00 AM – 5:00 PM
- Wednesday 9:00 AM – 5:00 PM
- Thursday 9:00 AM – 5:00 PM
- Friday 9:00 AM – 5:00 PM
- Saturday 9:00 AM – 5:00 PM
- Sunday Closed
Trusted by Homeowners Across the GTA
Areas We Serve Across the GTA
Our company builds basement suites for homeowners across the GTA, including
Mississauga
Toronto
Etobicoke
North York
Oakville
Burlington
Vaughan
Caledon
Every property has different conditions. We assess your basement, access, ceiling height, servicing, and structural needs first, then develop the right approach for your home.
Why Homeowners Choose GrandBuild Homes
A legal basement project requires careful planning, construction, and attention to municipal requirements. We bring these elements together with the experience and credentials to manage the work properly.
- Building Since 1995
- More than 30 years of residential construction experience across the GTA.
- HCRA Licensed
- Licensed to carry out residential construction work in Ontario.
- Tarion Registered
- Registered with Tarion for applicable new home warranty coverage.
- Fully Insured
- Comprehensive insurance coverage for the residential construction work we undertake.
Legal Basement Apartment FAQs
What makes a basement apartment legal?
A legal suite has to meet fire separation, egress, ceiling height, and ventilation requirements, and be registered with the municipality as a second unit. Without those, it’s just a finished basement, not a legal apartment.
What's the difference between a legal suite and a finished basement?
A finished basement is living space. A legal suite is a self-contained unit with a separate entrance, a second kitchen, fire separation, and municipal registration that you can legally rent, and a lender will count as income.
What happens if my basement apartment isn't legal?
An unregistered suite is hard to insure, hard to rent, and a problem when you sell. Building to code and registering it is what turns it from a liability into an asset.
How much does it cost to build a legal basement apartment?
Cost turns on three things: whether the lot supports a walkout, whether the ceiling height needs underpinning, and how much servicing has to be added. Those move the number more than finishes do. We establish them at the first visit, then price it fixed and itemized.
Does underpinning add a lot to the cost?
It can, because it involves lowering the floor slab to gain legal ceiling height. Whether you need it depends on your existing basement. We tell you at the first assessment.
Is there government funding to build a secondary suite?
Yes. There are secondary suite loan and incentive programs in Canada aimed at homeowners adding legal rental units. A properly built, registered suite is what makes you eligible and what a lender will count.
Will a legal basement suite add rental income?
That’s the point of doing it legally. A registered suite is one you can legally rent, and the rental income is something a lender will actually count toward your mortgage.
Do you handle the municipal registration?
Yes. We build to code and take the suite through second unit registration, so it’s legal on paper as well as in fact.
Do I need a separate entrance for a basement suite?
Yes. A legal suite needs a dedicated entrance, often a walkout or a side stair, that meets egress requirements.
Can any basement become a legal suite?
Not always. It depends on ceiling height, whether a walkout or separate entrance is possible, and servicing. We tell you what your specific lot and basement allow at the first visit.
Do you build basements that aren't rental units?
Yes. We build home gyms, theatres, guest suites, wine rooms, and in-law accommodation. The same standard of construction applies, but the design follows your needs.
Are you licensed and insured?
Yes. GrandBuild Homes is Tarion registered, HCRA licensed, fully insured, and has been building since 1995.
Which areas do you build basement suites in?
Across Mississauga and Toronto, including Etobicoke and North York, Oakville, Burlington, Vaughan, Caledon, and surrounding GTA communities.
See What You Can Build in Your Basement
Find out whether your basement can become a legal rental suite and what the project will require. GrandBuild Homes will assess your property and explain the next steps.