Want to build a cozy suite that compliments your main family home? You’re at the right spot. An in-law suite is a great way to have your family close to you while adding extra value to your property. We’ve compiled a detailed estimate cost breakdown to make your dream suite a reality.
How To Plan Your In-Law Suite?
Before you start, consider how the in-law suite will be used. Will it be a full-time residence for a parent or in-law, or more of a guest space? Plan out the number of rooms, amenities, and overall layout based on your answer.
For comfortable living, the suite should include: a bedroom, bathroom, kitchen, living area and laundry. Depending on your lot size, you can choose between a basement unit or backyard unit and a private entrance or even a separate outdoor space for added privacy.
How to Make Your In-Law Suite Accessible?
Planning for accessibility helps your in-laws live more comfortably as they age and also increases your property’s value. Team YKC can help you integrate these accessibility features:
- Wider doorways for wheelchairs and walkers
- Step-free entrances with gentle slopes instead of stairs
- Lever-style handles that are easier to grip than knobs
- Walk-in showers with non-slip flooring and grab bars
- Good hallway lighting to reduce the risk of falls
- Lower light switches and raised outlets for easier reach
Cost Breakdown
The average cost to build an ADU (Additional Dwelling Unit) ranges from $40,000 to $125,000 or more depending on your design preferences and needs. You can expect to spend about $100 to $200 per square foot, including materials and labor.
In-Law Suite Costs for Labour
- Architect: Local architectural services in Kingston will cost about 10% to 20% of the project’s total cost. For example, for a $100,000 in-law suite, you’d spend an additional $10,000 to $20,000 for an architect.
- Electrician: A new in-law suite will need electrical work, which costs an average of $50 to $100 an hour. Work also includes essential changes to your home’s current electrical system. For safety, the unit needs lighting leading to an outdoor exit, as well as smoke alarms and carbon monoxide detectors connected to the main home.
- Plumber: Both the bathroom and kitchen of the suite will require new plumbing, and the bathroom must be connected to the sewage system. Plumbers charge about $200 an hour for these intensive jobs. You can expect to spend:
- Water main installation: $600–$2,500
- Plumbing pipes: $300–$2,000
- Sewer installation: $1,500–$5,000
- HVAC: Depending on the size of the space, HVAC (heating, ventilation, and air conditioning) can be a relatively inexpensive extension of your existing systems, or require the installation of a new system. A new HVAC system costs around $7,500 on average.
- General Contractors: You can hire local addition and remodeling contractors in Kingston for many parts of the process, such as building the structure, painting the interior and exterior, laying floors, and installing windows. They’ll typically cost you 10 – 20% to oversee the entire project. Additional workers who build, install, and paint cost about $100 to $300 per laborer, per day.
In-Law Suite Material Prices
| Support beams and roof trusses | $15 to $30 per square foot. |
| Drywall and insulation | Drywall will cost $400–$600 for every 100 square feet, and insulation will cost $0.30–$1 per square foot |
| Foundation materials | $400–$700 for 100 square feet |
| Bathroom plumbing | $1,500–$4,000 for 100 square feet. |
| Plumbing fixtures | $400 to $2,000 for each plumbing fixture. |
| Electric meter | $2,000–$5,000. |
| Water heater | $600–$3,000. |
| Paint | $5,000 for interior, $8,000 for exterior. |
| Siding | Around $12 per sq. ft. |
| Windows | $100 to $1,500 per window. |
| Doors | $500 to $5,000 each. |
| Floors | $5 to $20 per square foot, with options like hardwood or marble costing more, while laminate or vinyl will be less expensive. |
Ready to build an ideal in-law suite in Kingston? Get in touch with Team YKC today!
7 Financing Options for Homeowners
Home Equity Line of Credit (HELOC)
A HELOC lets you borrow up to 65–80% of your home’s value, minus your remaining mortgage. You only pay interest on what you use, and rates are typically lower than personal loans. For example, if your home is worth $600,000 and you owe $300,000, you could qualify for up to $180,000 in HELOC funds.
Mortgage Refinancing
Refinancing allows you to replace your current mortgage with a new one that includes the in-law suite cost. Payments are spread over the full term (often 20–25 years), making monthly expenses more manageable. If you are unable to find a lower rate than your current, you’ll actually end up savings thousands in the long-term.
Second Mortgage
This option comes with higher interest rates, but it avoids disturbing your current mortgage. It’s best suited for short- to medium-term financing if you plan to pay it off quickly.
Personal Loans or Unsecured Lines of Credit
Smaller projects like adding a powder room or sunroom are better suited for this option. The trade-off is higher interest rates and shorter repayment periods, which may not be ideal for larger builds.
Government Rebates and Incentives
Ontario occasionally offers rebates for accessibility upgrades (like step-free entrances, widened doorways, or bathroom modifications) and energy-efficient improvements. While these programs change, checking resources such as the Canada Greener Homes Initiative can help offset costs for insulation, HVAC upgrades, or better windows. Municipalities sometimes also waive certain development charges for secondary suites.
Family Contributions or Shared Funding
Since an in-law suite benefits multiple generations, some families pool funds. Parents may sell their current home and contribute proceeds toward construction, or siblings may share costs if both plan to use the suite over time.
Home Additions Builder in YKC
Your Kingston Contractor brings hands-on experience and smart design to every in-law suite project, helping you create a home that feels like you — one that’s warm, comfortable, and built to perform through every season. We’ll help you integrate accessibility features that make intergenerational living easier and more connected.
Request a free consultation today.
