The materials, systems and repair methods we use, and how each one is chosen.
A soft, flexible material injected into the crack, which stops water sitting in it and eliminates the hydraulic pocketing that pounds the membrane below. The material needs to stay flexible through freeze-thaw movement rather than setting rigid and cracking again at the same line.
More detail: read the related project note.
No. This is the most common question from consulting engineers, and the injection pressure is not strong enough to lift the deck membrane. It is enough to displace water out of the joint and travel back along the path the water was using, which is all the repair requires.
More detail: read the related project note.
No. Hydrophobic resins like Joint Seal Flex do not foam or react when injected into a cavity full of moisture, which keeps the behaviour predictable in a wet joint. Because the resin is also heavier than water, it settles beneath standing water and pushes it ahead as more material is pumped in.
More detail: read the related project note.
By watching the injection pressure. If resin is still escaping into the structure, the pressure keeps moving. If the joint is filling and holding, the pressure climbs and stays high. That reading tells the operator whether to keep pumping or stop.
More detail: read the related project note.
A hydrophobic polyurethane injection resin — JSW uses Joint Seal Flex, manufactured in the United States for this application. It does not react with water, is heavier than water, and stays flexible after curing so the joint can keep expanding and contracting through Toronto's freeze-thaw cycles.
More detail: read the related project note.
A pressure relief drain is a pipe installed through the elevator pit wall that lets water behind the wall escape into the pit drain instead of pushing on the wall. We drill the wall with a one-inch bit, glue a pipe into the hole, and connect that pipe to a line running to the drain. When water builds up outside, it exits through the pipe rather than loading the wall.
More detail: read the related project note.
Relief drains create water flow around the outside of the elevator pit, and moving water carves voids in the surrounding ground and structure over time. It is a genuine drawback, not a technicality. It is accepted because the alternative — indefinite hydrostatic pressure on a block wall — degrades the wall far faster or collapses it outright.
More detail: read the related project note.
An upturn is the part of the waterproofing that continues from the pit floor up the wall, past the cold joint, so the seam is covered from both sides. The standard is one foot up the wall, and clients regularly ask for two. The fiberglass reinforcement starts about a foot out on the floor, crosses the corner, and turns up the wall.
More detail: read the related project note.
Power washing an elevator pit saturates the concrete, and saturated concrete will not let a coating bond or cure properly. It is the obvious first move and it is the wrong one. The pit is full of sediment, oil and debris that all has to come out, but it comes out mechanically — sweepers and grinders — not with water.
More detail: read the related project note.
No. An expansion joint is repaired across its full slab span, typically 20 feet, because the joint moves as a single unit. Repairing a short length leaves the rest of the run at its existing condition and the movement simply concentrates elsewhere along the joint.
More detail: read the related project note.
A pre-manufactured flexible profile inserted into the joint gap, which compresses and expands as the slabs move — shaped somewhat like a harmonica. Wabo, manufactured by Watson Bowman Acme, is a common brand, and their compression seals have a long track record in parking structures and similar horizontal applications.
More detail: read the related project note.
In practice the success rates are comparable, and a consulting engineer on one GTA condo board conceded that a top-side dig is not 100 percent effective either — because nobody knows every place the membrane and joint have cracked. Injection also addresses the leak directly at its exit point rather than working across a broad excavated area.
More detail: read the related project note.
Top-side excavation makes sense when the deck membrane is failing broadly rather than at one or two joints, or when the landscaping above is being replaced anyway. If the excavation cost is already being spent for other reasons, redoing the membrane at the same time is sensible. For a localized joint leak, it rarely is.
More detail: read the related project note.
A sounding test is tapping concrete with a specialised hammer or a metal rod and listening to the response. Solid concrete rings; delaminated concrete sounds hollow. It is the test that decides whether a crack gets injected or the surrounding area gets removed and patched, and it finds damage that looks completely sound to the eye.
More detail: read the related project note.
The water-reactive plug injected to stop an active leak holds for roughly four hours. It is a temporary measure by design, not a repair. That window is what the permanent work has to fit inside — the crack gets sealed and the waterproofing applied while the plug is still holding, so it cures dry.
More detail: read the related project note.
Water flowing out of a crack washes the repair material out before it can set. Anything you press into the opening — patching compound, cement, sealant — is carried away by the flow, so the repair never gets the chance to bond or cure. The water has to be stopped first, and stopping it is a different operation from repairing the crack.
More detail: read the related project note.
The equalizer pipe relieves water pressure from underneath the piston housing waterproofing so the installation is not pushed out from below. Without it, pressure builds under the sealed collar and eventually forces it out — like a cork from a champagne bottle. The pipe lets that water rise and discharge into the pit drain instead.
More detail: read the related project note.
Concreting around an elevator piston housing does not hold because the housing vibrates every time the elevator moves. That movement breaks every rigid seal between the steel housing and the concrete floor around it. The seal has to be flexible, which is why the detail is a rubberised collar rather than a rigid patch.
More detail: read the related project note.
In most cases, yes. Negative-side injection seals the joint from inside the parking garage, with no excavation of the soil, playground, or asphalt on the deck above. A typical 20-foot joint span takes about two days and requires roughly ten parking spots to be vacated, rather than a full closure.
More detail: read the related project note.
A cold joint is cut open at a 45-degree chamfer rather than as a square notch, because the angled face gives the patch material a wider bonding surface and removes the sharp internal corner a membrane would otherwise have to fold into. A square corner concentrates strain on one line and is where a coating splits first.
More detail: read the related project note.
The fibreglass reinforcement runs about a foot onto the floor and a foot up the wall, so the repair carries across the corner rather than stopping at the seam. Reinforcement that ends at the joint just relocates the weak line a few inches away. The overlap makes the floor, the joint and the wall behave as one continuous surface.
More detail: read the related project note.
Fibreglass reinforcement is not needed on every ceiling repair, and it is specified where the slab needs strengthening beyond what the patch alone provides. Where it is used, running it across the entire ceiling rather than only over the patches produces one continuous reinforcement layer instead of stiff patches in a softer field.
More detail: read the related project note.
A concrete crack wider than about five millimetres is routed open and filled rather than injected, because a liquid alone will not hold in a channel that size. Below one millimetre the crack is injected, since nothing with body to it will travel in. Between one and five millimetres either method can apply, depending on movement and water.
More detail: read the related project note.
Routing a crack removes sound concrete deliberately, so the finished channel is wider than the crack was — a four millimetre crack may open to seven. That is the intended outcome, not damage: the channel gives clean, sound faces for the adhesive to bond to. It does mean the crack is then repaired as a wide crack.
More detail: read the related project note.
Repaired cracks reopen because a crack moves far more, proportionally, than the concrete around it. If a slab contracts by two millimetres and the crack is five millimetres wide, that crack has opened by forty percent of its own width. A rigid filler cannot survive that strain; the fill has to bond chemically to both faces and move with the concrete.
More detail: read the related project note.
The difference is the bonding system, not the severity of the damage. Conventional patch concrete has no strength below about two inches, so a contractor using it must chip to two inches regardless of how deep the spall actually is. A contractor using an adhesive and polymer cement can match the repair depth to the damage.
More detail: read the related project note.
A 5 mm chemically bonded patch is as strong as the slab it is bonded to, because it acts as part of that slab rather than as a separate layer. A two-inch mechanically bonded patch is strong in itself but structurally independent, so it does not restore the slab's original depth. The bond decides the strength, not the thickness.
More detail: read the related project note.
Removing concrete to install an unbonded patch reduces the slab's effective structural depth for as long as the patch stays independent — take two inches out of eight and the structure works as six. A chemically bonded patch restores the full depth, because the two pours behave as one piece. Worth raising with your engineer on any thick repair.
More detail: read the related project note.
Polymer cement patches with Polyforce Plus adhesive cure in roughly four hours, comparable to how long conventional concrete takes to set, so most repairs take foot traffic the same day. Temperature affects it, and whatever coating goes over the patch usually governs the return-to-service date rather than the patch itself.
More detail: read the related project note.
Tap the patch with a hammer or drag a chain across it. A sound patch rings solid; a delaminated one gives a hollow, drummy note, because there is now an air gap between the patch and the slab. A stained hairline seam following the patch outline is the other reliable tell, and it usually appears before the patch is loose enough to hear.
More detail: read the related project note.
No. A failed concrete patch has to be chipped out and the substrate cleaned back to sound concrete before a new repair goes in. Patching over it bonds the new material to something already delaminated, so the repair inherits the failure. Removing old patches is routine for us and it is often a real portion of the labour on a garage.
More detail: read the related project note.
A mechanically bonded concrete patch has to be caulked around its perimeter and re-caulked every year or two, because the seam between patch and slab moves with temperature. A chemically bonded patch does not, because there is no seam — the patch and the slab are one piece. That recurring caulking is the hidden operating cost of the conventional method.
More detail: read the related project note.
Ordinary bag concrete packed around a penetration has nothing bonding it to the existing wall and no waterproofing layer over it. It shrinks and cracks as it cures, and once groundwater sits against it under pressure the concrete degrades and the water finds its way back through. A repair like that commonly loses most of its effectiveness within a few months.
More detail: read the related project note.
About two days for a single penetration, including the excavation, the repair itself, and the cure time before backfilling. That assumes the penetration is roughly five feet down and the ground above is soft landscaping. Hard landscaping or asphalt over the excavation adds reinstatement time and cost.
More detail: read the related project note.
It depends on where the damage is. A crack that passes through the slab requires a completely empty pool, because the crack cannot be opened against water pressure. A localised repair on a wall needs only a partial drain, down to just below the damage. A floor patch needs a full drain but the refill starts about fifteen minutes later.
More detail: read the related project note.
Marbelite is a soft material and it deadens the sound of a hammer, so sounding through a finished pool surface gives unreliable results. The one usable signal beforehand is blistering or cracking in the finish above a defect, which sounds different when tapped. Once the coating is ground off, the whole surface can be mapped in an afternoon.
More detail: read the related project note.
Marbelite has to cure under water, so the pool is filled the same day the finish goes on. Leave it dry overnight and the finish cracks. The same rule applies at small scale: a localised marbelite floor patch starts refilling about fifteen minutes after the last trowel.
More detail: read the related project note.
On an epoxy-coated pool, physical contact with the dry wall can stain it permanently. At one Bayview Avenue building a drained pool had a wall wiped down with a towel, and the wiped areas turned yellow while untouched walls stayed clean. It is a reaction between bromine, the epoxy coating and oxygen, triggered by the contact, and it cannot be cleaned off.
More detail: read the related project note.
Ask the engineer to confirm the specification against the pit's actual conditions before the work goes out to tender. Crystalline waterproofing needs a substrate free of oil and days of controlled hydration, and it cannot be overcoated with a protective membrane. An elevator pit is oil-contaminated and needs that oil protection. The specification is often carried across from below-grade or transportation work, where those conditions are met.
More detail: read the related project note.
Crystalline waterproofing is not a base for a protective membrane, and in an elevator pit that matters because the concrete needs protecting from hydraulic oil as well as from water. The manufacturers' answer to crystalline's rigidity is a flexible latex topping from their own product family, which adds movement tolerance rather than oil and chemical resistance. The concrete itself is left exposed to what the elevator equipment sheds.
More detail: read the related project note.
Crystalline waterproofing does not bridge cracks. It seals static hairline cracks up to around 0.4 mm by growing crystals into them, and the crystals are brittle, so a crack that keeps moving keeps reopening. In an elevator shaft the wall moves every time the car runs. That is why a flexible membrane that stretches across a microcrack works there and a rigid treatment that fills it does not.
More detail: read the related project note.
Where heavy wheel traffic crosses, plan on twelve to eighteen inches either side of the channel, taken below slab level to a compacted stone base. On a recent sixty-foot edge rebuild we broke back roughly a foot to a foot and a half and dug down more than a foot before reaching sound material. The width is set by where good substrate starts, not by how wide the damage looks.
More detail: read the related project note.
No. Layers that end up buried and sealed under the finish can be ordinary materials, including compacted stone and the concrete that shapes the fall. It is generally only the final inch or so that has to meet the food-grade requirement, applied as a base coat and a top coat. Specifying certified material through the full depth of a repair is a common and expensive mistake.
More detail: read the related project note.
In genuine office and administrative space, yes. The trap is that some rooms look administrative and are not. We were once asked to use a cheaper epoxy in what was described as an office area, and on walking it we found the micro testing lab where quality control work is done. We flagged it, the engineers agreed, and it was finished in food-grade material.
More detail: read the related project note.
Coving is a sloped fillet formed where the floor meets the wall, typically up to about three inches at roughly forty-five degrees. It removes the sharp internal corner entirely, so water runs out instead of sitting and dirt has nowhere to lodge. It is formed in the same system as the floor rather than installed as a trim, so there is no seam at the junction.
More detail: read the related project note.
Levelling feet leave a gap between the plinth and the floor, and that gap is dark, permanently damp and impossible to clean or inspect. Sealing around the foot closes it, so nothing can get underneath and a glance is enough to confirm the area is clean. We have done close to forty of these at one plant and none has failed, against a previous detail that was not lasting four months.
More detail: read the related project note.
Woven fiberglass is the correct reinforcement under a wall coating and non-woven geotextile is not, because of thickness. Woven fiberglass is about the thickness of one or two sheets of paper; non-woven geotextile is four to five times that and absorbs far more coating. The 150 to 300 gram per square metre range builds a heavy edge, and that edge is what delaminates.
More detail: read the related project note.
A coating peels back at the reinforcement edge when the topcoat is terminated level with the fiberglass instead of past it. With too little waterproofing epoxy or polyurea above the edge, the edge curls, delaminates and lets moisture in behind the coating. Carried past a razor-cut woven fiberglass edge, the same detail holds. The run must also finish on coating at the bottom, never on exposed fiberglass.
More detail: read the related project note.
A wobbly railing is actively destroying the concrete it is anchored into. Metal and concrete expand at different rates, so temperature change opens a gap at the anchor; water enters that gap, freezes and cracks the concrete, while oxygen reaching the steel corrodes it from inside the base. The wobble is the symptom, and the damage compounds every winter it is left.
More detail: read the related project note.
Concrete repair needs air temperature above plus five degrees Celsius, because below that ice crystals form in the substrate and no repair material will bond to them. Plus ten degrees is where most materials genuinely perform. Between five and ten, the morning-to-evening temperature swing creates enough dew that the work needs materials tolerant of a damp surface.
More detail: read the related project note.
Tightening the fixing on a loose handrail rarely holds, because the movement comes from the concrete around the anchor having cracked apart rather than from the bolt working loose. There is often nothing sound left for the fixing to bear against. Building staff can identify and report the movement, but the repair is a concrete repair, not a fastening job.
More detail: read the related project note.
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