Question 1

Can precast concrete stairs be repaired, or do they have to be replaced?

Accepted Answer

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.

Question 2

How long does a concrete stair repair take?

Accepted Answer

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.

Question 3

Do the stairs have to be closed while they are repaired?

Accepted Answer

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.

Question 4

Is spalling on exterior concrete steps a safety issue?

Accepted Answer

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.

Question 5

What makes a repaired staircase non-slip?

Accepted Answer

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.

Question 6

How high should liquid flashing go up the wall?

Accepted Answer

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.

Question 7

Why does one side of a building fall apart while the other side looks fine?

Accepted Answer

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.

Question 8

Does a breathable membrane still keep rain out?

Accepted Answer

A breathable balcony coating allows water vapour to escape from the concrete slab while preventing liquid water from getting in. Concrete always carries some moisture, and a coating that blocks it in both directions traps that water where it can freeze and crack the slab from inside. Vapour permeability is the property to ask a supplier about.

Question 9

Would bare concrete have lasted longer than cheap paint?

Accepted Answer

Bare concrete outperforms a non-breathable paint, because a bare slab dries out after every wetting while a sealed one cannot. This is not an argument against coating balconies, since a correctly specified breathable system lasts far longer than bare concrete, but a cheap impermeable paint shortens the life of the slab.

Question 10

Can a new balcony coating go straight over the existing one?

Accepted Answer

No, where the existing coating is a non-breathable paint that has already trapped moisture. It is ground back to bare concrete first, because recoating over it seals the same water under a new surface. Where the existing system is sound and breathable, a recoat may be possible after adhesion testing.

Question 11

Should we coat a parking garage ceiling with epoxy?

Accepted Answer

No. Epoxy on a parking garage ceiling acts as a vapour barrier on the wrong side of the slab, trapping moisture travelling down from the deck above. Use a breathable coating in that position, for the same reason a balcony needs one. Ordinary paint is little better, because it delaminates and holds water while it lifts.

Question 12

How can you tell trapped moisture from ordinary surface wear?

Accepted Answer

Trapped moisture shows as blistering, coating lifting at the edges, or crack patterns radiating out from beneath a film that still looks intact. Ordinary wear shows as thinning and scuffing in traffic areas without lifting. If the building is under twenty years old and cracking, suspect the coating first.

Question 13

Does a balcony coating need an engineer to specify it?

Accepted Answer

Not always, but on a multi-unit building it is worth having one name the vapour permeability requirement in the specification rather than leaving it to the lowest bid. That single line in a tender is what stops a cheap impermeable paint being substituted, which is the failure this article describes.

Question 14

Is a spalling balcony edge dangerous?

Accepted Answer

A spalling balcony edge over an occupied area is a falling-material risk rather than only a durability problem, because the loose concrete sits directly above walkways, balconies or parking below. Where reinforcement is visible at the edge, have an engineer assess it rather than scheduling routine patching through the maintenance budget.

Question 15

How far should a balcony coating extend over the edge?

Accepted Answer

A balcony coating should carry over the last foot of floor, down the full vertical face, and a few inches back underneath past the drip edge. Stopping at the vertical face lets water track around the bottom corner onto unprotected concrete, which is the most common reason an edge repair does not last.

Question 16

What is a drip edge on a balcony?

Accepted Answer

A drip edge is a groove cut into the underside of a balcony slab near the outer face that makes water fall clear instead of running back along the soffit. It only works if it is intact and if any coating extends past it, which is why the detail is carried underneath rather than stopped at the face.

Question 17

Can balcony edge repairs be done without a swing stage?

Accepted Answer

Often yes. On low-rise and mid-rise buildings the edge is reached from the balcony itself with the right access equipment and fall protection. Higher elevations and continuous facade work usually need a swing stage, which is why edge repair is normally scheduled alongside other facade work rather than run on its own.

Question 18

Why does new flooring on a balcony hide the real condition?

Accepted Answer

Tile, vinyl and other surface finishes sit on top of the structural slab and conceal cracking underneath rather than stopping it. On a Milton retirement residence the cracks only became visible once old vinyl flooring came off, and they had to be filled before any membrane could be installed over them.

Question 19

Is edge repair a maintenance item or a capital project?

Accepted Answer

Wrapping a sound balcony edge during a scheduled coating cycle is maintenance. Rebuilding an edge that has already delaminated, with exposed reinforcement, is a capital repair needing engineering involvement. The distinction is whether steel is visible, which is why the inspection matters before the budget is set.

Question 20

How often should balcony perimeter caulking be replaced?

Accepted Answer

Balcony perimeter caulking is inspected on the same cycle as the building's other exterior sealants and replaced when it hardens, cracks or pulls away from either face, rather than on a fixed interval. Exposure varies sharply by elevation, so a sun-facing balcony needs it sooner than a shaded one on the same building.

Question 21

Why is water coming into the unit rather than showing on the balcony?

Accepted Answer

Water entering at the balcony-to-wall joint travels along the seam, which runs underneath the wall and into the building line, so it often appears as an interior complaint before anything is visible outside. A dry-looking balcony does not rule out a failed perimeter joint as the source of the leak.

Question 22

Is caulking a permanent fix or a temporary one?

Accepted Answer

Maintained caulking at the balcony-to-wall junction is a permanent approach rather than a stopgap, provided it is a specialty sealant, coved properly, and replaced as it ages. The fibreglass and injection build-up exists for joints left open long enough to need it, so it is the consequence of skipping maintenance.

Question 23

Can the caulking be replaced without redoing the whole balcony?

Accepted Answer

Yes. Perimeter caulking is a standalone maintenance item and does not require the balcony coating to be replaced at the same time, as long as the existing coating is sound. Where the coating is already failing, doing both together avoids paying twice for access and mobilisation.

Question 24

What does coving mean in a sealant application?

Accepted Answer

Coving means the caulking is run so it rounds off the corner instead of being pressed flat into a square angle. The curved profile sheds water, and it also stops moisture, dust and dirt collecting and packing into the edge. The same shape is used in food-grade facilities with a completely different material, though the cove on a balcony is much smaller in cross-section.

Question 25

Does this joint appear on every balcony?

Accepted Answer

It appears on any balcony where the exterior wall bears on the balcony slab, which covers most cantilevered concrete balconies in Toronto high-rise and mid-rise construction. The seam runs the full width of the balcony at the base of the wall, so it is a continuous path rather than an isolated defect.

Facade & balcony