Twice the House on the Same Footprint

Often, yes — but only an engineer's assessment can say so for your house. Foundation walls, footing size and soil, and which interior walls are bearing decide it. Post-war bungalows frequently have the capacity; where they fall short, footings can be enlarged or walls reinforced before the addition, and that work is priced into the project rather than discovered halfway through.

Yes, always. It is a structural addition and a change to the height and area of the house, so it needs a building permit with architectural, structural and mechanical drawings, and it has to comply with your municipality's zoning for height, lot coverage and setbacks. Several GTA municipalities have mature-neighbourhood rules that limit second storeys specifically — check your city's page on this site, or ask us to check the zoning before you commit to a design.

Design and permits typically take two to four months depending on the municipality, and construction of an addition typically runs three to five months after that. The roof-off period inside that schedule is measured in days, not weeks, because it is planned around the framing crew and the weather forecast.

Usually not during the structural phase. With the roof off and the floor system going in, the house has no ceiling and no services for a period, and the safest and fastest approach is an empty house. Some partial second storeys can be built with the family in the untouched half; we tell you honestly which kind of project yours is.

It depends on what your lot and zoning give you. A rear addition uses yard and counts against lot coverage; a second storey uses height and keeps the yard. On a narrow urban lot the second storey is often the only way to double the space; on a wide suburban lot a rear addition may be simpler and cheaper to build. Where both are possible, the deciding factor is usually which rooms you need more of.

That is the main-floor decision that shapes everything else, and we settle it at design stage. The Ontario Building Code sets the rise, run, headroom and width, and the stair has to land somewhere that does not wreck the main-floor plan. A well-placed stair often improves the main floor; a badly placed one is the most common regret in a top-up.

Only if you want it to, and only some materials can. Matching forty-year-old brick is rarely exact, so many second storeys are finished in stucco, siding or panel as a deliberate contrast, with the original brick kept on the ground floor. The Scarborough bungalow in our project stories took that approach with stucco and black trim. Either way the roofline, windows and trim are designed so the house reads as one building.

Frequently. Doubling the conditioned floor area changes the heating and cooling load, and the mechanical design in the permit set will show whether the existing furnace and air conditioner can carry it or whether a larger unit or a second zone is needed. The electrical panel is checked the same way, and any upgrade is done under an Electrical Safety Authority permit.