Adding a second storey to a bungalow

The short answer

Often, yes. Many bungalows and side-splits in Waterloo Region have the lot, the zoning and the structure for a second storey. The deciding questions, in order:

1. Can the foundation and walls carry it? An engineer answers this before any design work.
2. Does zoning allow the height? 11.0 m in Kitchener's main residential zones, 10 m in Waterloo's R1 zone and 11 m in Cambridge's R1 and R2 zones, with extra rules in some older neighbourhoods and heritage districts.
3. Is building up better than building out? A rear addition, a finished basement or a backyard unit sometimes delivers the space with less disruption.

Start with the structure

A bungalow's footings, foundation walls and main-floor walls were sized for one storey and a roof. A new floor, its walls and a new roof add load, so the first step is an engineer's assessment of what is there: the footings, the foundation, the bearing walls, and the beam and posts in the basement.

• When it carries the load, the new floor is framed on the existing walls, sometimes with added beams or posts.
• When it needs help, footings can be enlarged or underpinned, new posts and beams added in the basement, or steel used to carry loads to points that can take them.
• The ceiling is not a floor. A bungalow's ceiling joists were usually sized to hold up a ceiling, not people and furniture, so a new floor system is normally built for the upper level.

That is why we bring an engineer in during feasibility, before you pay for design. It is far better to learn early whether the structure works, and what it will take.

What zoning allows

Height is the zoning rule that matters most for a second storey. The footprint does not change, so the setbacks and lot coverage the house already meets usually stay the same.

The cities also measure height differently. Kitchener measures from the highest finished ground around the house to the highest point of the roof. Waterloo and Cambridge measure a pitched roof to the midpoint between the eaves and the ridge, and Waterloo measures from the average ground level along the front of the house.

Older neighbourhoods and heritage districts

• Kitchener's central neighbourhoods: in the areas mapped in Appendix C of By-law 2019-051, an addition that raises the house by more than 1.0 m is capped at 9.0 m in height when both neighbouring houses are under 6.5 m tall.
• Kitchener's heritage districts (St. Mary's, Upper Doon, Victoria Park and Civic Centre): exterior changes such as additions usually need a heritage permit as well as a building permit.
• Waterloo's MacGregor-Albert district (the RC1 zone): an addition must sit entirely in the rear yard and be no taller than the existing house, and needs a heritage permit.
• Cambridge's heritage districts (Blair Village, Dickson Hill and Main Street) and designated properties: exterior changes may need heritage approval.

About 20% of Kitchener properties are still under the older By-law 85-1, some Cambridge residential lands remain under its older By-law 150-85, and every city has zones beyond the ones above, so check your lot on the city's zoning map. If a design does not fit a rule, a minor variance from the Committee of Adjustment is the route; our guide to planning an addition covers the fees and timing.

Designing the new floor

• The stairs. A new staircase takes a slice of the main floor, so where it lands shapes the plan of both levels. It is often the decision everything else follows.
• Plumbing. A new upstairs bathroom is simplest above the existing bathroom or kitchen, where drains and venting can run straight down.
• Heating and cooling. The furnace and ducts were sized for one floor. Kitchener asks for an HVAC designer's information when an addition is 25% or more of the existing heated area, and Waterloo for an HVAC form when it adds 15% or more to the floor area. A second storey on a bungalow usually crosses both thresholds, so plan for new ductwork or a separate system upstairs.
• Energy efficiency. The new level is built to the Building Code's energy efficiency requirements, and Kitchener's list of forms for an addition includes an Energy Efficiency Design Summary.
• The outside. Roof pitch, window proportions, brick or siding and the line where old meets new decide whether the house looks original or added on to.

Full storey, partial storey or dormers

• A full second storey over the whole footprint gives the most space and the simplest roof.
• A partial second storey over part of the house, often the bedroom wing, adds less space and can sit more comfortably on a street of bungalows.
• Raising the roof or adding dormers can turn the attic into a storey and a half where the existing roof and structure allow it.
• Building over an attached garage adds a room or suite without taking the roof off the main house.

Permits, drawings and who designs it

A second storey is an addition, so it needs a building permit in all three cities, designed to the 2024 Ontario Building Code, in effect since January 1, 2025. Electrical work needs its own permit from the Electrical Safety Authority.

Expect structural drawings as well as plans and elevations. Waterloo, for example, requires an engineer's seal on roof trusses and an engineer's or designer's seal on engineered floor joists. Both Kitchener and Waterloo let homeowners draw plans for their own house, but Kitchener notes that some drawings must be designed by a professional engineer when the design falls outside the Building Code's prescriptive requirements, and Waterloo says larger or more complex projects need an architect, engineer or BCIN-qualified designer. Kitchener and Waterloo both aim to finish the first review of a complete house application within 10 business days.

Living through it

A rear addition is closed in before the wall into the house is opened. A second storey is different: the roof comes off the house you live in. Plan to be away for at least part of the project, especially from the day the roof comes off until the new level is closed in and weathertight. Our guide to staying through a renovation covers the options, including telling your insurer before work starts.

How the build runs

1. Feasibility: zoning, height and heritage status checked, and an engineer's assessment of the structure.
2. Concept design for both floors and the exterior.
3. Minor variance, if the design needs one.
4. Permit drawings and engineering, then the application. Windows and trusses are ordered so they arrive on time.
5. Reinforcement below: footings, posts and beams, as the engineer specifies.
6. Roof off, new level framed and the shell closed in as quickly as the weather allows.
7. Windows, then the rough-ins for plumbing, heating and electrical, each inspected.
8. The stairs connected, then insulation, drywall and finishing on both floors.

When building out or down makes more sense

• A rear addition, if the lot has room inside the setbacks and you would rather stay home throughout. See home additions.
• A finished basement, for a family room, office or guest suite, usually the most affordable space a house can add. See basement renovations.
• A basement or backyard unit, when the goal is a separate suite for a parent or tenant. See our basement apartment guide and backyard homes guide.

For a wider look at the options, see our home addition ideas.

How we plan a second storey

We check zoning, height and heritage status at the free site visit and bring an engineer in to assess the structure before any design money is spent. If a second storey works, we design it to look original to the house, prepare the drawings and permit application, and run the build with one project manager. If it does not, we will tell you, and show you what would.

See home additions in Kitchener, home additions in Waterloo or our home additions service.