Balconies, steps, soffits and exterior concrete on occupied buildings.
7 answers.
Can precast concrete stairs be repaired, or do they have to be replaced?
Precast concrete stairs with cracked or spalling nosings can be repaired in place in the large majority of cases. Replacement is rarely necessary unless the structural slab of the staircase itself has failed. The repair rebuilds the step geometry with sculpted polymer cement and then coats the staircase; replacement means demolition and recasting at roughly four to five times the cost.
More detail: read the related project note.
How long does a concrete stair repair take?
A typical concrete stair repair takes about two days — one day of preparation and one of application — and the stairs can be used almost immediately afterwards, because the materials cure in hours rather than days. Recasting the same staircase takes one to two weeks with the stairwell closed throughout.
More detail: read the related project note.
Do the stairs have to be closed while they are repaired?
A staircase wide enough to work on in halves does not have to close: the left side is repaired while residents use the right, then the sides switch. On a narrow staircase the closure is measured in days rather than weeks. This matters because a stairwell is emergency egress and cannot simply be taken out of service.
More detail: read the related project note.
Is spalling on exterior concrete steps a safety issue?
Spalling on the nosing of a concrete step is a tripping hazard and a safety violation, because the walking edge is exactly where people put their weight. It is also where water and road salt reach the reinforcing steel. Deferring the repair means the rebar corrodes and the scope grows from a surface repair into a structural one.
More detail: read the related project note.
What makes a repaired staircase non-slip?
The non-slip surface comes from the top coat — either a UV-resistant coating that is non-slip in itself, or a membrane with an anti-slip aggregate broadcast into it. On exterior stairs this is not optional. A smooth coated step in a Toronto winter is worse than the damaged concrete it replaced.
More detail: read the related project note.
How high should liquid flashing go up the wall?
Three feet above grade is the working height for liquid flashing on a Toronto building. Salt and snow rarely reach past two feet and most saturation concentrates around the one-foot mark, so three feet clears the exposure with room to spare. Four feet starts to change how the building looks without protecting anything the first three feet did not already cover.
More detail: read the related project note.
Why does one side of a building fall apart while the other side looks fine?
Freeze-thaw cycles accumulate per elevation, not per building. A sun-facing wall thaws in winter sunlight and refreezes at sunset, collecting far more cycles than a shaded wall that freezes once and stays frozen. Wind exposure, vehicle traffic, and where snow is banked and salted add to it. As a rule of thumb, about one hundred freeze-thaw cycles is equivalent to twenty-five years of wall life.
More detail: read the related project note.
