Custom Home Additions: What You Should Know

Discover which custom home additions—like sunrooms, extra bedrooms, or in-law suites—deliver the best return. Adding space to your home isn’t just about comfort; it’s also about making a smart investment. This article breaks down which additions are most likely to boost your home’s value, what they typically cost, and planning tips to get the best long-term results.

1. Kitchen Expansions

The kitchen is one of the most valuable spaces in any home. Expanding with a custom addition—whether it’s creating more room for a larger island, adding pantry space, or opening up the layout—can significantly increase functionality and appeal.

Why it adds value: Buyers consistently rank updated kitchens as a top priority, making this one of the strongest home improvements for ROI.

Typical cost in Ontario: $25,000–$75,000 depending on finishes, size, and layout changes.

2. Primary Suite Additions

Adding a primary suite with a walk-in closet and ensuite bathroom instantly elevates your home. Today’s buyers are looking for private, spa-like retreats that combine comfort and convenience.

Why it adds value: A well-designed primary suite can increase resale value and help your home stand out in a competitive market.

Typical cost in Ontario: $40,000–$100,000+ depending on size and features.

3. In-Law Suites and Income Units

Multi-generational living and income properties are in high demand. A basement suite, above-garage unit, or ground-level addition provides flexibility for families and the potential for rental income.

Why it adds value: Versatility and income potential make in-law suites one of the most impactful custom home additions that add value.

Typical cost in Ontario: $60,000–$150,000 depending on square footage and amenities.

4. Extra Bedrooms or Bathrooms

If your home feels tight for your family—or potential buyers—adding a bedroom or bathroom can make a big difference. Families especially value homes with ample sleeping space and at least two full bathrooms.

Why it adds value: More bedrooms and bathrooms expand livability and directly increase resale appeal.

Typical cost in Ontario: $20,000–$60,000 depending on size and complexity.

5. Sunrooms and All-Season Rooms

Ontario winters are long, which makes sunrooms and all-season rooms especially appealing. They bring in natural light, extend living space, and create a year-round area to enjoy the outdoors from the comfort of indoors.

Why it adds value: Enhances lifestyle and curb appeal while adding usable square footage.

Typical cost in Ontario: $25,000–$80,000 depending on size, insulation, and materials.

6. Garage Additions

A garage is more than a place to park—it’s storage, workshop space, and added functionality. Whether attached or detached, garages are highly valued in Ontario real estate.

Why it adds value: Practical, versatile, and a strong selling feature.

Typical cost in Ontario: $30,000–$70,000 depending on size and whether it’s attached.

Balancing Cost and Value

While each of these additions can add significant value, the smartest investment depends on your home, neighborhood, and long-term goals.

Smart planning tips:

• Don’t overbuild compared to surrounding homes—you may not get the ROI at resale.
• Prioritize additions that solve real problems for your family today (like space or comfort).
• Consider how long you’ll stay in the home—longer stays mean more personal return on comfort and energy efficiency.
• Work with an experienced contractor to plan for both your needs and market appeal.

Final Thoughts

The smartest custom home additions that add value are those that improve your quality of life now while making your home more appealing in the future. Kitchens, primary suites, in-law suites, and sunrooms are all high-impact projects that can boost both comfort and resale value.

At MD Construction, we’ve been helping homeowners in St. Thomas, London, Port Stanley, and West Elgin design and build additions that balance lifestyle and investment for over 35 years.

👉 Book a consultation today and discover which addition will add the most value to your home.