Barrhaven, south-west Ottawa
Home additions in Barrhaven
Additions in Barrhaven are most realistic on detached lots, in Old Barrhaven and on the larger lots elsewhere, subject to zoning setbacks. On riverside lots inside the regulated area, anything that enlarges the house needs Rideau Valley Conservation Authority approval as well as a building permit.
Typical rear or side addition, one storey in Barrhaven, with HST $122,000 to $163,600 $305 to $409 per sq ft for 400 sq ft
AI imageWhat additions cost in Barrhaven
Typical project totals and the price per square foot, with HST, by type of job and finish level, priced for suburban Ottawa. Choose a row to open it in the estimator with Barrhaven prices.
| Type of addition | Economy | Mid-range | Premium |
|---|---|---|---|
| Rear or side addition, one storey400 sq ft | $105,700 to $141,600$264 to $354 per sq ft | $122,000 to $163,600$305 to $409 per sq ft | $153,800 to $206,200$385 to $516 per sq ft |
| Second storey700 sq ft | $150,600 to $202,000$215 to $289 per sq ft | $178,200 to $239,000$255 to $341 per sq ft | $233,500 to $313,100$334 to $447 per sq ft |
| Bump-out100 sq ft | $58,100 to $77,900$581 to $779 per sq ft | $65,900 to $88,300$659 to $883 per sq ft | $78,500 to $105,300$785 to $1,053 per sq ft |
Prices are estimates based on published Ottawa and Ontario price guides, checked October 2026. They are not an offer. A firm written quote follows a site visit. Prices for Barrhaven include about 2% over central Ottawa for travel and delivery.
Homes in Barrhaven
What the local housing means for additions.
Old Barrhaven was started in the 1960s by developer Mel Barr. Longfields was mostly built from the early 1990s, Stonebridge from 2000, and Barrhaven South and Half Moon Bay after 2006, on what the City described in 2006 as farmland.
- Homes in Longfields and the earlier parts of Stonebridge are roughly 20 to 35 years old, an age when original cabinets, counters, tubs and vanities are often replaced.
- Detached, semi-detached and townhouse homes are the types the City allows to host a secondary suite, which makes a basement suite worth considering.
- On townhouse streets with small yards, a rear deck is the main way to add outdoor space; additions are more realistic on detached lots.
Permits and approvals
What to check in Barrhaven before additions work starts. Rules change, so we confirm what applies to your address.
Rideau Valley Conservation Authority
Barrhaven sits between the Jock River and the Rideau River, both inside the Rideau Valley Conservation Authority's area. RVCA reports that about 16% of the Jock River-Barrhaven catchment lies inside its regulation limit, and it mapped flooding and slope hazards along the Rideau from Hogs Back to Kars in 2017. RVCA treats work inside the existing walls, roof and foundation that does not change the use as generally not needing its approval; enlarging the house, changing its use or adding a unit does.
Building permits
The City generally requires a building permit to finish a basement, move or remove walls, alter plumbing, add or enlarge windows and doors, and build an addition. Replacing kitchen cabinets without moving plumbing fixtures usually does not need one. Electrical work is inspected separately by the Electrical Safety Authority.
Trees
On urban lots of one hectare or less, the City's Tree Protection By-law requires a permit to remove or injure a distinctive tree, which the current by-law sets at 30 cm or more across at chest height. Footings and trenches near big trees are planned around their roots. The thresholds have changed in recent years, so we check the by-law in force.
Zoning
Additions and larger decks have to meet the zoning setbacks, height and lot coverage for your lot. Most of Ottawa's new Zoning By-law 2026-50 is in force (the parts not under appeal took effect from March 2026), and where a provision is still under appeal the stricter of the old and new rules applies, so we check the rules for your address before design starts.
A sample quote
A typical Ottawa home addition, priced task by task. Open it, then change it to suit a house in Barrhaven.
Good to know
How much does a home addition cost in Barrhaven?
A mid-range rear or side addition, one storey of about 400 sq ft typically comes to $122,000 to $163,600 with HST, based on published Ottawa and Ontario price guides checked October 2026. With economy finishes the same job is about $105,700 to $141,600; with premium finishes, about $153,800 to $206,200. Size, the state of the house and what you add all move the number, so use the estimator for your own project. A firm quote follows a site visit.
Does being near the Jock River change anything?
If your lot is inside the Rideau Valley Conservation Authority's regulated area, enlarging the house, changing its use or adding a unit needs RVCA approval. Interior work inside the existing walls and foundation generally does not. We check the mapping for your address.
Do you work in all of Barrhaven?
Yes, from Old Barrhaven to Longfields, Stonebridge, Half Moon Bay and the newer streets near Cambrian Road. Barrhaven addresses are priced at suburban rates in the estimator.
Planning a home addition in Barrhaven?
Price it in the estimator with Barrhaven rates, then send it to us. We confirm the numbers on a site visit and follow up with a written quote.