Six of the thirteen additions we build. The full list is under Services in the menu.
$385-$525 per sq ft
A full new upper floor over an existing footprint, engineered for the load path below it.
Second storey addition
$325-$475 per sq ft
A rear addition, bedroom, office, or similar ground-floor room.
Room addition & home extension
From roughly $60,000
A code-compliant secondary dwelling unit with its own entrance, sized under the City's floor-area rules.
In-law suite & ADU addition
$75,000-$150,000
Extra floor space built specifically to reshape the kitchen, not a renovation within the existing walls.
Kitchen addition
$50,000-$100,000
A new bedroom built to the Ontario Building Code's egress-window requirement from the start.
Bedroom addition
$7-$23 per sq ft to finish
New living space below grade, with egress and window-well work priced separately where it applies.
Basement additionYour own number depends on scope, site access and what the foundation has to do, which is why every quote follows a site visit.
$50,000-$150,000
Single-room addition, bedroom or office: $50,000-$100,000
Kitchen addition: $75,000-$150,000
Sunroom addition: $25,000-$70,000
Garage addition, single or double: $50,000-$120,000
$325-$625 per sq ft
Single-storey rear or side addition: $325-$475 per sq ft
Second-storey addition: $385-$525 per sq ft
Small bump-out extension: $415-$625 per sq ft
Attic conversion: $50,000-$120,000
From roughly $60,000
In-law suite or secondary dwelling unit build-out: roughly $60,000-$120,000
Basement finishing (walkout excavation priced separately): $7-$23 per sq ft
Garage conversion to living space: $25,000-$85,000
Egress window and window-well work quoted after inspection
Three things we settle before a single wall gets drawn.
We confirm setback and lot coverage against the City of Ottawa Zoning By-law before we design anything, so the addition fits your lot from the first drawing.
Each floor level with a bedroom, including a basement secondary suite, needs a window with an unobstructed opening of at least 0.35 sq m under the Ontario Building Code, with no dimension under 380 mm. It is a common reason an addition fails inspection, so we design to it from day one.
Each of our area pages shows a recent project from that community, with photos from the job.
Under Ottawa’s new Zoning By-law (2026-50), most urban neighbourhood lots need a rear yard of 25 percent of lot depth, never less than 6 m, with no more than 7.5 m required. Rural and village lots follow their own zones. Those rules decide whether a rear addition or a second-storey addition fits your lot, before a single drawing is worth paying for. We check them in the first conversation, not after a design fee has been spent.
Much of Ottawa sits on Champlain Sea clay, left behind when the Champlain Sea drained roughly 12,000 years ago. The City of Ottawa’s own geotechnical guidance states that this soil’s compressibility has to be addressed by most development built on it. Footings in this region are commonly founded to about 1.5 m to get below frost depth. Neither of those facts changes what an addition looks like on the surface, but they change what the foundation underneath it costs, which is why we look at the ground before we price the ground floor.
We walk the property, measure the lot and check the addition against the City of Ottawa Zoning By-law setback and coverage rules before anything is designed.
Drawings sized to what the lot allows, submitted for a City of Ottawa building permit with the fee and review timeline set out in writing.
Footings founded below frost depth and to suit the soil on your lot, then framing built to the approved drawings.
Interior finishing, inspection sign-off, and a walk-through so you know exactly what was built and to what standard.
One recent job in each of the 15 Ottawa-area communities we build in. Tap a photo to see it full size, or the city name to see that area's page.
Attic conversion
Porch enclosure
Basement finishing
Great room addition
Single-storey addition
Rear room addition
Side addition
Room addition with glass doors
Basement finishing
Dormer addition and covered entry
Built-in shelving and bench
Lower-level renovation
Rear extension and pergola
Family room addition
Basement finishing
Reviews given to us directly by clients.
Home Additions Experts Ottawa built a beautiful family-room addition for our home. The team communicated clearly, stayed organized, and made sure the new space blended perfectly with the original house.
We hired them to add an extra bedroom and bathroom to our Ottawa home. The workmanship was excellent, and the team kept us informed throughout the entire project. We are very pleased with the finished space.
The team managed our home addition professionally from the initial planning stage through construction. They answered our questions, respected our property, and delivered a result that exceeded our expectations.
Our new second-storey addition looks like it has always been part of the house. The builders paid close attention to every detail and kept the worksite clean and organized. I would gladly recommend them.
Home Additions Experts Ottawa transformed our small home by creating the extra living space our family needed. The process was well managed, the crew was courteous, and the final result is both practical and beautiful.
Setback, lot coverage and secondary-suite floor-area limits are confirmed against the City of Ottawa Zoning By-law before drawings start, not after.
Each bedroom floor, including a basement secondary suite, gets an egress opening sized to Ontario Building Code Div. B 9.9.10, because it is a common reason an addition fails inspection.
Design and permit work sits on its own line of your quote, and we submit the application to the City of Ottawa for you.
Every addition is different, so any workmanship warranty is set out in your written quote, job by job, never as a blanket guarantee.
Every quote is broken into its real parts and priced line by line, so you can compare it with another contractor’s quote. We don’t price a job over the phone.
A second-storey addition and a garage addition are not the same kind of spend. Full-project prices include design, permit, foundation, framing and finishing. Per-square-foot prices cover the structural build alone. Ask which kind of number you are being given, because the two are not comparable without knowing the scope behind them.
Short answers on permits, setbacks and prices. The full list is on the FAQ page.
Yes. Any addition that adds floor area needs a City of Ottawa building permit. Fees typically scale with construction value, roughly $12 to $20 per $1,000 declared, with permit-fee ranges commonly running $1,500 to $6,000 for a single-storey addition and $4,000 to $12,000 for a second-storey addition.
Under Ottawa's new Zoning By-law (2026-50), most urban neighbourhood lots need a rear yard of 25 percent of lot depth, never less than 6 m, with no more than 7.5 m required. Rural and village lots follow their own zones. Corner lots and rural or village zones follow different numbers, which is why we check the by-law against your lot first.
In most cases, yes. Ottawa allows additional dwelling units on most residential lots, with limits on the number of units per lot. The unit needs its own entrance, plus fire separation and egress under the Ontario Building Code. We confirm your lot's limits under the new Zoning By-law before designing.
Room-scale additions run $50,000-$150,000, structural additions are priced per square foot, and secondary suites are priced as a full build-out, as the pricing table above breaks down. Use our cost calculator for a range based on your project, then we confirm the real number after we see the property.
Getting the permit issued typically takes 4 to 12 weeks depending on scope, and a full secondary-suite application with mechanical and fire-separation review can run 7 to 14 weeks. Construction time is added on top of that. We give you a realistic combined timeline in writing before anything starts.