Riverside South, south Ottawa
Home additions in Riverside South
Additions in Riverside South are most practical on detached lots, subject to zoning setbacks and lot coverage. Near the Rideau River or Mosquito Creek, inside the regulated area, anything that enlarges the house also needs Rideau Valley Conservation Authority approval.
Typical rear or side addition, one storey in Riverside South, with HST $122,000 to $163,600 $305 to $409 per sq ft for 400 sq ft
AI imageWhat additions cost in Riverside South
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 Riverside South 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 Riverside South include about 2% over central Ottawa for travel and delivery.
Homes in Riverside South
What the local housing means for additions.
The community was built by a small number of developers, among them Urbandale, Richcraft and Claridge, first under a 1992 Gloucester plan and then under City plans from 2005. The 2009 plan aimed for a mix of about 42% singles and semis, 37.5% townhouses and the rest stacked townhouses and apartments. Honey Gables, three streets on the west side of River Road, dates from about 1950.
- Kitchens and bathrooms from the late 1990s and 2000s are reaching the age when cabinets, counters, tubs and vanities get replaced.
- Singles, semis and townhouses are the types the City allows to host a secondary suite, so basement suites come up often.
- On townhouse streets a rear deck is often the main outdoor space; additions are more realistic on detached lots.
Permits and approvals
What to check in Riverside South before additions work starts. Rules change, so we confirm what applies to your address.
Rideau Valley Conservation Authority
Riverside South lies along the Rideau River and Mosquito Creek, both in the Rideau Valley Conservation Authority's area. RVCA mapped the Rideau's flood and slope hazards in 2017 and has extended its Mosquito Creek mapping in and around the community. 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 Riverside South.
Good to know
How much does a home addition cost in Riverside South?
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 Mosquito Creek affect what I can build?
If your lot is inside the Rideau Valley Conservation Authority's regulated area along the creek or the river, enlarging the house, changing its use or adding a unit needs RVCA approval. We check the mapping for your address.
Do you work in all of Riverside South?
Yes, including the older streets of Honey Gables and the new streets east of Limebank Road as they are built. Riverside South addresses are priced at suburban rates in the estimator.
Planning a home addition in Riverside South?
Price it in the estimator with Riverside South rates, then send it to us. We confirm the numbers on a site visit and follow up with a written quote.