Second Storey Designs
That Don't Look Like an Add-On

Drive through Alta Vista or Lynwood Village and count the bungalows that grew a second floor in the last fifteen years. About one in three of them looks fine. The other two thirds look exactly like what they are: a 1960s ranch with a 2010s box dropped on top, like someone parked a shed up there and forgot to take it down.

That look is not the price point. Plenty of cheap second storeys read fine. Plenty of expensive ones read terrible. The difference is design literacy and four specific decisions that the architect or contractor either gets right or doesn't.

Here's what makes a second-storey addition look original to the house, with a real Alta Vista project as the example.

What the tacked-on look actually is

The "addition" look isn't one thing. It's the cumulative effect of four mistakes that compound. Get all four wrong and the addition shouts. Get any two wrong and it still looks off. Get all four right and the house looks like it was always two storeys.

The four mistakes:

1. Roof pitch on the addition doesn't match the existing roof pitch.
2. Dormer scale and proportion wrong, usually too big and too few.
3. Window grid on the second floor doesn't align with the windows on the first.
4. Siding or cladding doesn't run continuously from ground to roof, leaving a horizontal break that screams "this is where the old house ended."

Mistake 1: Roof pitch mismatch

1960s Ottawa bungalows were built with low-slope hip or gable roofs, typically 4:12 or 5:12. When a bungalow gets a second storey, the new roof pitch should match the bungalow's original pitch, not jump to the 8:12 or 10:12 that builders default to because it's easier to vent and looks "more modern" on a render.

A 4:12 bungalow with a 9:12 second-storey addition reads as two different houses stacked. The eye sees the change of angle and registers it as wrong before the brain figures out why.

The fix: keep the new roof at the same pitch as the original. If you must change pitch (sometimes for room height or for a future solar array), do it asymmetrically with a deliberate design move, like a shed roof over a stair tower that contrasts on purpose. Never split the difference. Splits look accidental.

The cost impact: usually zero. A 5:12 roof costs the same as a 9:12 roof in Ottawa, with maybe a 3 to 5 percent variance in framing materials.

Mistake 2: Dormer scale and count

Dormers exist to bring light and headroom into a sloped roof. They are a feature that pre-existed second-storey additions by 200 years. The right way to use them is to design the addition with dormers from the start, in proportions and counts that match Ottawa house traditions.

Common dormer mistakes:

• One huge shed dormer spanning most of the roof. Reads as a half-floor that ran out of money.
• Three skinny gable dormers too closely spaced. Reads as fussy and over-decorated.
• One dormer dead-centre on a long roof. Reads as a single eye looking at you.

The proportions that work: gable dormers about one-third to one-half the width of the bay below, spaced to align vertically with the windows on the first floor. On a typical 30-foot-wide bungalow, two evenly spaced gable dormers (each maybe 6 to 7 feet wide) reads better than three.

Mistake 3: Window alignment

The single sharpest reading test of a well-designed second storey is whether the second-floor windows align vertically with the first-floor windows. When they do, the house reads as composed. When they don't, the house reads as accidental.

This is harder than it sounds because the second-floor layout (bedrooms, bathrooms) doesn't naturally produce windows in the same places where a 1960s living-room and dining-room layout put them downstairs. The job of the architect is to lay out the upstairs floor plan to put windows where they need to be on the elevation, then make the floor plan work around that constraint.

It's a discipline. Most builder-grade additions don't bother. They lay out bedrooms first and put windows wherever the bedroom interior wants them, with no reference to the elevation. The result is windows offset by 18 inches from the windows below, which the eye registers immediately.

Mistake 4: Cladding break at the storey line

The fourth and most common mistake. The original bungalow has brick to the eave. The addition gets sided in vinyl or fibre cement above. There's a visible horizontal line where the brick stops and the siding begins. The line happens at the floor level of the new second storey, which is exactly where the eye looks for a "this is where the old house ended" cue.

The fixes, in order of preference:

1. Run a single material from ground to roof. Re-clad the existing first floor in the same material as the new addition. It adds to the project budget, scaled to the size of the house and the cladding you choose, but it is the single most powerful move for cohesion.
2. Use the storey line as a deliberate horizontal datum. Add a real architectural belt course (brick rowlock, stone lintel, wood band board) that wraps the entire house, so the line is intentional and ornamental rather than accidental.
3. Lower the cladding break below the storey line. Bring the brick or stone up onto the second floor by 24 to 36 inches, and let the siding take over above. This breaks the eye's expectation that "siding starts where the new storey starts."

The Alta Vista project

The house: 1962 brick bungalow on a 60-by-110-foot Alta Vista lot. 1,180 square feet on the main floor, three bedrooms, one bath, no basement bedroom. Owners had three kids and needed two more bedrooms and a second bath, plus a primary ensuite.

The decisions we made

Roof: kept the existing 5:12 pitch on the new second storey. The addition reads as the same house, taller. Adding a contrasting flatter section over the new primary suite gave us extra ceiling height there without breaking the main roof line.

Dormers: two gable dormers on the front, each 6 feet 6 inches wide, aligned over the existing front windows. Each dormer holds a single 36-by-60 window, mullion-aligned with the original brick.

Window alignment: we designed the second-floor plan around the elevation. The primary suite ended up at the back of the house with two side windows aligned over the existing kitchen window and back door. The two front bedrooms each got a single window centred in their dormer. This required the upstairs hallway to dog-leg around the stair, which was ugly on the floor plan but invisible on the elevation.

Cladding: we re-clad the entire house in James Hardie panel and trim, charcoal grey for the field and white trim for windows and corners. The 1962 brick was painted-over (poorly) in the 90s and was never going to look great. Removing the visual reference to the old brick removed the last "this is where the addition starts" cue.

The result

From the street, the house reads as a 1940s-era two-storey, not a 1962 bungalow with a 2025 addition. Neighbours assumed we tore down and rebuilt. We didn't. The original main floor is intact, structurally and spatially. The new second floor sits on the existing foundation with reinforcement at the load-bearing perimeter walls.

"My mother visited and asked when we moved. We didn't. We just stopped looking like the bungalow she remembered."

What drove the cost

The Alta Vista second-storey addition was a full-scope project. Rather than a single sticker figure, here is where the budget actually went, ordered from the heaviest cost drivers to the lightest:

• Second-storey framing, sheathing, and roof — the largest single driver on any storey-up
• Two new bathrooms, plumbing rough-in, and fixtures — finish level drives most of the variation here
• Re-cladding the entire house in fibre cement — the cohesion move that makes the addition disappear
• Insulation, vapour barrier, drywall, and paint across the new floor
• Three bedrooms with finishes, flooring, and trim
• Windows (12 second-floor units plus 4 ground-floor replacements)
• Electrical — new subpanel, full second-floor wiring, and fixtures
• Demo and re-roof of the existing structure
• HVAC extension — new ductwork, a new return, and second-zone control
• Hardwood — main floor refinish plus new flooring on the second storey
• Engineering, design, BCIN drawings, and permits
• Foundation reinforcement at the load-bearing perimeter

The cost of a second-storey addition in Ottawa depends heavily on whether the existing main floor needs work, the finish level you choose, and how much of the envelope you re-clad. Skipping the re-cladding trims the budget, but the addition will read as an addition. We strongly recommend the cladding for any project where the existing brick or siding is tired. Every project gets a detailed written breakdown so you can see each cost driver and decide where to invest before any commitment.

The four-rule checklist

Before you sign a design contract for a second-storey addition, ask the architect or contractor four questions:

1. What roof pitch are you proposing on the addition, and how does it relate to the existing roof?
2. Can you sketch the front elevation before finalizing the second-floor plan?
3. How will the second-floor windows align vertically with the first-floor windows?
4. What are we doing about the cladding break at the storey line?

If the answer to any of those is "we'll figure that out later" or "it'll be fine," walk. The answers to those four questions are the design.

Our service overview for Ottawa home additions walks through the full process, including the BCIN-stamped drawings and 3D renderings we provide before any framing starts. Free 48-hour feasibility review at 613-862-4555.