Preston Street is the former runoff route from Dow’s Great Swamp down to the Ottawa River at Nepean Bay, until Colonel By built the dam that QE Driveway runs along the top of. This means significant portions of the ground along Preston are peat or soft materials.
At the site of a new three storey infill on Preston (six apts above 3 retail) crews bored supporting pipes deep into the ground. The pipes were cut off at the same level down in the future basement. A concrete “box” was poured in place on top of each post. Gravel was poured into the basement between the posts and packed down. Then the footings shown in the fourth picture were poured in place on top of the concrete boxes on top of the steel posts, plumbing was put in, and gravel packed in to make the subfloor. All this, just to get to the basement floor level.
Then the plywood forms shown in the fourth picture were unpacked and set out for the walls to be poured, as shown in picture 5. the basement consists of tiny rooms, probably lockers. Note that the building on the right – Photo Lux – is supported by a steel beam and concrete footings. The old wood frame brick veneer house that previously occupied this site was on such a tilt that it made me seasick just looking at it. Its kitchen must have been crazy like the one at the museum of science and technology.