Renovating in Alta Vista and the inner suburbs

This is the most interesting renovation market in Ottawa and the most technically awkward. Alta Vista, Elmvale Acres, Carlington, Overbrook and the older parts of Nepean are largely 1950s and 1960s bungalows and side-splits on generous lots, owned in many cases by the original family or bought by a second generation who intend to stay.

Two constraints define the work. The first is ceiling height. A 1955 bungalow basement commonly gives 1.85 to 1.95 m under the joists and less under the main duct, which sits right on the 1.95 m the Building Code asks for a basement living space and suite. That is why underpinning, which is lowering the basement floor with an engineer's design and sequenced excavation under the existing footings, is a normal conversation in this part of the city and almost unheard of in Kanata.

The second is that these houses are the ones most likely to sit on soft Champlain Sea clay, and the clay is why underpinning here is an engineering exercise rather than a digging exercise. It is also why the Building Code's clay foundation depth of 1.2 m matters when an addition goes on beside an existing footing.

The compensating advantage is lot size. Post-war lots in Alta Vista are wide and deep by modern Ottawa standards, so rear additions and garden suites often work here without a variance where they would not on a 1990s subdivision lot. Check lot coverage and rear yard setbacks early, because generous lots make people optimistic and the by-law is still the by-law.