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Home Extensions and Bump-Outs in Ottawa
More room on the main floor without going up or moving. OGC designs, permits, and builds rear and side extensions and bump-outs that tie into your house so the new space looks like it was always there.
Grow Your Home Without Moving
A kitchen that is too small, no main-floor family room, a primary suite that never fit: as home extension contractors in Ottawa, we hear it every week. A home extension is the most direct way to gain real square footage on the floor where you already live, by building out into your yard and tying the new space into your existing rooms.
Not every project needs a full extension. A bump-out adds just a few feet where it counts, room for a kitchen island, a breakfast nook, or a larger bathroom, at a fraction of the cost of a large addition. Whether you want a modest bump-out or a full rear extension, we design, permit, and build it under one roof.
For second storeys and suites, see our home additions in Ottawa. We also build sunrooms and garage additions.
- Enlarge a kitchen, family room, dining area, or primary suite
- Bump-outs add space where you need it, without a full addition
- Foundation, framing, and exterior matched to your existing home
- Fixed pricing, permits handled, and a 7-year warranty
Which Extension Fits Your Home
The right extension depends on the room you want, how much yard you have, and what the house can tie into. These are the ground-floor extensions Ottawa homeowners ask us for most.
Kitchen Extension
Push the back wall out to get an island, a pantry, or a proper eating area. One team builds the extension and the kitchen inside it.
Kitchen renovations in Ottawa
Family Room Extension
A room-sized space at grade, often with a vaulted ceiling, opening off the kitchen. You get the space without a second storey.
How long an addition takes
Rear or Side Extension
A single-storey room on a new foundation. Rear-yard depth sets how far back you can go. Side yards are tighter, and close to the lot line the wall needs a fire rating.
Permits for home additionsBump-Out
A few feet of extra room for a kitchen, a dining nook, or a bathroom. A small cantilever can hang off the floor framing within code limits. Anything larger, or carrying more load, goes on footings or piles, and the engineer decides.
Addition and extension costsPrimary Suite Bump-Out
Push a bedroom wall out to fit a walk-in closet or an ensuite. It is often the difference between a bedroom and a primary suite, without moving to get one.
Ask about your bedroomGoing Up Instead
When the yard is too small to build out, a second storey adds space without using more of your lot. We will tell you which way your house and lot point.
Second floor additionsA Main-Floor Primary Suite, Added On
Every bedroom is upstairs and the stairs are getting harder. Or the primary bedroom never had room for an ensuite. A main-floor primary suite addition fixes both on one level: a single-storey extension on its own foundation, usually 300 to 400 square feet, holding a bedroom, an ensuite, and a walk-in closet off a hallway you already have.
This is a bigger job than a primary suite bump-out, so it is built as a new room. The bedroom needs a window that opens from the inside without tools, with at least 0.35 m² of clear opening and no dimension under 380 mm. The ensuite drain has to reach your existing plumbing, so we plan the layout around where it can tie in.
If the suite is for aging in place, we design for that from the start: a step-free entry, wider doorways, a curbless shower, and blocking in the walls for grab bars. Done at the design stage, these cost very little. If it also needs its own kitchen and entrance, it becomes an in-law suite, which has its own rules.
A 300 to 400 square foot suite usually lands between $100K and $200K, in the full-room extension range below. The ensuite finishes are the biggest variable.
- Bedroom, ensuite, and walk-in closet on one level
- Bedroom window sized to the Building Code
- Optional step-free design for aging in place
- Roofline and cladding matched to your house
Mudrooms and Entry Additions
Ottawa winters come in through the door: boots, salt, hockey bags, and a closet's worth of coats. A mudroom addition gives all of it a place before it reaches the kitchen, with a bench, hooks, closed storage, a floor that handles meltwater, and a second door between the house and the cold.
Most are small, from a few feet pushed out at the back or side door to an enclosed front vestibule. Small does not mean simple. A heated mudroom is part of the house, so it sits on footings at least 1.2 m deep on clay, or on engineered piles, and it has to fit inside your setbacks like any other room.
On our Front and Rear Additions project, one front entry addition brought in a mudroom and a powder room together. A mudroom can also link the house to a new attached garage. See our garage additions.
Most mudroom and entry additions fall in the bump-out and small-extension range, $40K to $100K. A powder room or a larger footprint moves it up.
- Bench, hooks, and storage planned around your family
- Flooring that stands up to salt and meltwater
- A second door that keeps winter air out of the house
- Powder room or laundry folded in where plumbing allows
How a Home Extension Actually Runs
Building out means a new foundation, new structure, and a clean tie-in to your existing home. Here is the design-build process OGC follows to take your extension or bump-out from first idea to a finished, inspected space.
We start at your home to see how you want to use the space, look at your yard and where you can build, and talk honestly about budget before you commit to anything.
- On-site review of the room, the yard, and your goals
- Early read on setbacks and how far out you can build
- Ballpark budget range so you can plan with real numbers
Our designers turn your ideas into a real layout and renderings, so you can see how the new space flows into your existing rooms before we build.
- Floor plans designed around how the space connects
- 3D renderings of the interior and matched exterior
- Revisions until the design is right
In Ottawa, rear and side yards set how far you can build out. Two zoning by-laws apply while appeals of the new one continue, and the stricter rule governs. We confirm what your lot allows, engineer the foundation, and submit the permit. The City's first-review target for a house is 10 business days once the submission is complete.
- Rear and side yard setbacks confirmed for your lot
- Stamped foundation and structural drawings
- Building permit and any minor variance handled by OGC
Before construction begins, you get a detailed, fixed-price contract covering the full scope. The number you approve is the number you pay for that scope.
- Line-by-line scope with allowances written down
- Fixed price for the agreed scope
- Schedule with milestone dates
On clay, footings under heated space go at least 1.2 m deep, deeper where the engineer calls for it, and helical piles are an accepted alternative. Then we frame the new space and tie the roofline, siding, and floor levels into your existing home so the extension looks original, not bolted on.
- Engineered footings or helical piles
- Framing, roof, and windows matched to your home
- Building envelope sealed and inspected before interior work
We finish the new space end to end, then walk the completed extension with you before the City's final inspection and hand over your warranty.
- Electrical, plumbing, and HVAC extended into the new space
- Drywall, flooring, trim, and paint completed
- Final City inspection booked and your 7-year warranty handed over
Extensions and Additions We've Built
A sample of additions, main-floor renovations, and new space we have designed and built for Ottawa homeowners.
See a full project story: Front and Rear Additions, a new front entry and a rear three-season room on one house.
Why Ottawa Homeowners Choose OGC
200+ verified reviews across Google, Houzz, and HomeStars, from homeowners who trusted us to open up the back of their house.
True Design-Build, One Roof
Design, engineering, permits, and construction all live in-house. No finger-pointing between an architect and a builder, just one accountable team from first sketch to final inspection.
One Dedicated Project Manager
A single project manager runs your entire extension and stays reachable by phone or text the whole way through. No handoffs, no gaps, no wondering who is in charge.
See It Before We Build It
Every project starts with full 3D renderings so you can see the new space and matched exterior before construction begins. Change it on screen, not on site.
Fixed Pricing, No Surprises
You approve a fixed price for the scope in your contract, with any allowances written down. Our price-match policy applies to comparable, itemized quotes from GOHBA and RenoMark members.
7-Year Warranty
OGC backs every extension with a 7-year warranty. Adding to your home is a major investment, and your peace of mind should match it.
Recognized by Ottawa's Building Industry
OGC is a member of the Greater Ottawa Home Builders' Association (GOHBA), a RenoMark renovator, and a member of the Canadian Home Builders' Association (CHBA). Our work has been featured on CTV and CBC.
What Ottawa Homeowners Say About Us
The Hard Parts of Building Out in Ottawa, Handled
An extension adds new foundation and structure to your home, and Ottawa's rules and ground shape what you can build. Here is what we manage on every project.
Two zoning by-laws are in force at once while appeals of the new one are heard, and the more restrictive of the two applies. Under By-law 2026-50, the rear yard in a Neighbourhood zone is 25% of the lot depth, at least 6 m and never more than 7.5 m required, and that provision is under appeal. Inside the Greenbelt, By-law 2008-250 also requires the rear yard to be at least 25% of the lot area. We confirm the numbers for your lot before design.
A bay window can project up to 1 m into a yard. A room bump-out cannot: it has to fit inside the setbacks like the rest of the house. Floor joists that carry roof loads can cantilever only 400 mm or 600 mm depending on their depth (Ontario Building Code 9.23.9.9), and anything beyond that is engineered.
For heated space on clay, footings go at least 1.2 m deep (Ontario Building Code Table 9.12.2.2), and deeper where frost or the engineer requires it. Helical piles are an accepted option. Winter excavations need frost protection, and we plan for it.
A wall less than 1.2 m from the lot line needs a 45-minute fire rating and rated protection on any openings, which effectively rules out windows. A foundation within 3 m of the property line needs a professional engineer to design the excavation. Side yards are tight too: no single side yard under 0.6 m or 1.2 m, depending on the subzone.
The new part is built to new-construction code, and the existing house cannot be left worse off (Ontario Building Code Part 11). Energy efficiency for the addition follows the additions path in the code's energy standard. Then the roofline, cladding, and floor levels are matched so the extension reads as original.
Trees 30 cm in diameter and up are protected on most urban lots, and the City may ask for a permit, an arborist's report, and a tree protection plan. A required setback can shift by up to 3 m to save a protected tree. Additions in a Heritage Conservation District need a heritage permit: Rockcliffe Park and New Edinburgh are districts, the Glebe as a whole is not.
What a Home Extension Costs in Ottawa
Cost depends on whether you are doing a small bump-out or a full extension, the new foundation required, and your finishes. Here is the range Ottawa homeowners are working within.
Bump-Out vs Full Extension
A cantilevered bump-out within Ontario Building Code limits hangs off the floor framing and needs no new foundation, which keeps it lower in the range. Anything larger, or carrying more load, needs footings or piles and sits higher.
Foundation and Size
Home extensions in Ottawa generally run $300–$500+ per square foot all-in. The new foundation is a major cost, so the bigger the footprint, the higher the total.
Finishes and Tie-In
A new kitchen or bathroom, higher-end finishes, and reworking the existing rooms the extension connects to all move you up the range.
Want the full breakdown by project type? Read our detailed guide to home addition and extension costs in Ottawa, or get an instant estimate.
Ottawa Home Extension Questions
A bump-out is a small push-out of one room, often just a few feet, to make space for a kitchen island, a nook, or a larger bathroom. A small one can be cantilevered off the floor framing within Ontario Building Code limits. A home extension is larger: a full room or more on its own new foundation. We build both.
Most projects fall between about $40,000 for a small bump-out and $250,000+ for a large main-floor extension, or roughly $300 to $500 per square foot all-in. A new foundation is a major cost, which is why a cantilevered bump-out, where the code allows one, comes in lower. See our full home addition and extension cost guide for a detailed breakdown.
Not always. Ontario Building Code limits how far floor joists that carry roof loads can cantilever: 400 mm for 38 x 184 mm joists and 600 mm for 38 x 235 mm or deeper. Within those limits a bump-out can hang off the floor framing. Anything larger, or carrying more load, is engineered and goes on footings, which on clay sit at least 1.2 m deep under heated space, or on helical piles.
Yes. Any addition to your home needs a City of Ottawa building permit, and permit fees are charged on the new floor area. The City's first-review target for a house is 10 business days once the submission is complete, and inspections run from excavation through to final. Some projects also need a minor variance. OGC prepares the drawings and handles the entire process. Here is more on permits for home additions in Ottawa.
It depends on your rear-yard depth, your side yards, and any easements. Ottawa has two zoning by-laws in force while appeals of the new one are heard, and the stricter rule applies, so we check both for your lot before design. If you are short, a minor variance through the Committee of Adjustment is the usual route, and if the yard is simply too small, building up may be the better answer.
Construction on a small addition runs about 3 to 6 months, plus design and permitting beforehand. A bump-out sits at the shorter end, and a large multi-room extension takes longer. The City's first permit review is typically 10 business days once the submission is complete. See our guide on how long a home addition takes in Ottawa.
Usually, yes. Because an extension is built into the yard first, we keep the existing exterior wall closed until the new space is weather-tight, so most homeowners stay home through most of the build. We will tell you honestly what to expect for your specific project.
Home Extension Contractors Across Ottawa
OGC designs and builds home extensions and bump-outs across Ottawa and the surrounding region. Pick your area for local detail on additions.
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