Why Elevator Pit Leaks Happen (and How They’re Fixed From the Inside)

If you manage a building, sooner or later you’ll get the call: “There’s water in the elevator pit again.” It’s one of the most common calls we get from property managers and strata councils, and there’s a simple reason for it. The pit is usually the lowest point in the building. Any water that’s looking for a way in finds the pit first.

Elevator pit leaks aren’t something to mop up and forget. In this article we’ll explain why elevator pits leak, how a leaking pit gets fixed from the inside without digging up the building, and how to plan the work with your elevator company so nobody gets surprised. (If you already know you need the repair, our elevator pit waterproofing and leak repair page covers how we do it.)

Why elevator pits leak

An elevator pit is a concrete box set below the lowest floor. It’s poured in pieces, it’s full of joints and openings, and it often sits right in the groundwater. Here are the paths we find most often when we stand in a wet pit:

• Below the water table. The pit goes deeper than the rest of the building, so it’s often sitting in groundwater. The water is pushing on the concrete all the time, not only when it rains.
• Construction water. Rain and runoff collect in the pit while the building goes up. If the concrete wasn’t detailed well, that water finds every weak spot before the building is even finished.
• Cold joints between the walls and the slab. A cold joint is where one pour of concrete meets another that has already set. The two pours never fully bond, which leaves a seam water can follow.
• Shrinkage and stress cracks. Concrete shrinks as it cures and moves as the building settles. Hairline cracks that would be harmless in a dry wall become leak paths in a wet pit.
• Honeycomb. Honeycomb is concrete that wasn’t fully consolidated when it was poured, so it’s left with voids and gravel pockets. It acts like a sponge.
• Tie holes. The steel ties that held the formwork together leave small holes through the wall. If they weren’t sealed properly, each one is a little pipe straight through the concrete.
• Pipe and drain penetrations. Anywhere a pipe, drain or conduit passes through the concrete is a joint between two different materials. Sump pits beside the elevator pit have the same problem, which is why we also do sump repair around pipes and barrel rings.
• A failed or missing exterior membrane. Many pits were meant to be protected by a waterproofing membrane on the soil side. Over time that membrane can tear, debond or turn out never to have been fully installed.
• Nearby excavation. When a new building goes up next door, dewatering and digging can change how groundwater moves around your building. A pit that was dry for years can start leaking.

Most wet pits have several of these at once, which matters for the repair.

Why standing water in a pit is not just a nuisance

It’s tempting to pump out a damp pit and move on. But standing water in an elevator pit causes real damage over time.

• Corrosion. The pit holds steel and electrical equipment: rails, buffers, cylinders on hydraulic units, switches and wiring. Constant moisture rusts steel and damages electrical gear.
• Mould and odour. A dark, wet concrete box is a good home for mould, and the smell can travel up the hoistway.
• Shutdowns. Elevator contractors don’t want to work in, or run equipment over, a flooded pit. Water can lead to the car being taken out of service until the problem is dealt with.
• Deficiency claims. In newer buildings, a leaking pit often turns up on a deficiency list. For builders and developers, it’s a line item that has to be cleared before they can move on.
• Damage to the concrete. Water moving through concrete can carry minerals out of it and reach the reinforcing steel inside. If you see rust staining or concrete breaking away, bring in the building’s engineer.

Why pits are repaired from the inside (negative-side waterproofing)

To understand how a pit gets fixed, it helps to know two terms.

The positive side is the side the water comes from. For an elevator pit, that’s the outside face of the concrete, against the soil. The negative side is the opposite face, the inside of the pit where you see the water arrive.

On a new building, the pit should be waterproofed from the positive side before it’s backfilled. On an existing building, that face is buried under the building, the parkade or the street. You can’t dig it out. So the repair has to happen from the negative side: from inside the pit, against the water pressure.

That is negative-side waterproofing, and it’s what we do. Water is still pushing in from the soil, so a paint or film on the inside surface won’t hold.

The repair has to stop the active water first and then become part of the concrete itself. That’s why we use Kryton’s Krystol crystalline system, which reacts with moisture to grow crystals inside the pores and fine cracks of the concrete. If you want the details, we’ve written about how crystalline waterproofing works.

How elevator pit leaks get repaired, step by step

Every pit is different, but the sequence is the same.

1. Isolate the pit with the elevator contractor

Nobody goes into a pit until the elevator company has taken the car out of service, confirmed lockout and given safe access. We work in the window they give us.

2. Find every active path, not just the puddle

The puddle tells you where water collects, not where it comes in. We look at every joint, crack, tie hole, honeycombed patch and penetration. If we only fix the obvious one, the water moves to the next weakest spot.

3. Stop the running water

We’d rather see a leak running than guess at a dry stain, because flowing water shows us exactly where the path is. Active leaks get cut out and packed with Krystol Plug, a rapid-setting hydraulic cement made to stop flowing water, even under pressure. It’s part of Kryton’s Krystol Leak Repair System.

4. Chase and pack joints and defects

Cold joints, cracks and tie holes are opened up into a clean channel (a “chase”) and packed with crystalline repair material. Honeycombed areas are cut back to sound concrete and rebuilt.

5. Crystalline treatment, plus injection where needed

We apply Krystol T1 crystalline slurry to the concrete, with a further Kryton crystalline coat where the surface needs a stronger top coat. If a crack’s width or movement calls for it, we use compatible injection as well.

6. Leave it dry enough to put the car back in service

Before we leave, we inspect the whole pit and take photos for the strata or property manager’s file. The goal is a pit that’s dry enough for the elevator company to return the car to service.

Planning the work with your elevator company

Pit work takes a bit of planning, because an elevator is out of service while we’re in there. Here’s what to think about:

• Access window. Your elevator contractor decides when the car can come out of service. Talk to them early, and if the building has more than one elevator, plan around peak times and move-ins.
• Confined space. Pits are tight, enclosed spaces. The work has to be set up and done safely, and that’s part of why we plan it with the elevator company rather than squeezing it in.
• Noise and dust. Cutting chases makes some noise and dust. We keep both down as much as we can, but give residents or tenants notice.
• Water handling. If the pit has standing water, it needs to be pumped down before we start. We’ll sort out with you and the elevator company who does that.

Before the site visit, send us photos of the pit, a note on when it leaks, the building’s age and your elevator company’s contact (details in the questions below). Our quote comes from a site look, not a phone guess. Standing water, active flow and the joint layout all change the method. Leaking pits are often one item on a longer list, so we also handle strata and building deficiency repairs such as parkade, patio and foundation leaks.

Groundwater in Richmond and other low-lying areas

Location matters. Much of Richmond sits on the Fraser River delta, which is flat, low and built on sand and silt laid down by the river. The Province of B.C. notes the area’s flat topography and shallow groundwater table, and that development there often needs dewatering.

An elevator pit in ground like that can sit in water for much of the year, and low-lying parts of Surrey and the Fraser Valley floodplain are similar. Add our long wet season, from fall storms through spring, and it’s easy to see why a pit that looks fine in August can be wet by November.

Common questions

Can you repair an elevator pit while water is still coming in?

Yes, and we prefer it. Running water shows us exactly where the leak path is, so we don’t have to guess from a dry stain. We stop the active flow first with a rapid-setting hydraulic plug, then treat the joints and concrete around it with crystalline materials. The pit does need to be pumped down so we can work safely.

Do you have to excavate outside the building to fix a pit leak?

Usually not. On an existing building the outside of the pit is buried under the structure, so digging isn’t practical anyway. We repair from inside the pit, which is called negative-side waterproofing. The materials we use are designed to work against water pressure from the soil side and become part of the concrete rather than sitting on top of it.

How long will the elevator be out of service?

It depends on the pit: its size, how many leak paths there are, how much water is coming in and how much prep the pit needs. We can’t give a fair answer until we’ve seen it. After the site visit, we plan the work window with you and your elevator contractor so the building knows what to expect before anything starts.

Is crystalline waterproofing the same as a coating or paint-on sealer?

No. A coating or sealer sits on the surface, and in a wet pit with water pushing from behind it can blister and peel. Crystalline materials react with moisture and the cement in the concrete to form crystals inside the pores and fine cracks. The concrete itself becomes the barrier. We don’t sell a painted-on coating as a pit repair.

Can you fix the sump pit at the same time?

Often, yes. Sump pits sit at the same low level as the elevator pit and leak for similar reasons, especially around pipes and barrel rings that were never properly waterproofed. If you have water in both, tell us when you book the inspection and we’ll look at them together.

What should I send for a quote?

Photos of the pit (wide and close-up), a note on when it leaks (after rain, all the time, or since nearby construction), the building’s age, and your elevator company’s contact. Then we’ll book a free inspection. We quote from a site look, not from a phone description.

Book a free pit inspection

If there’s water in your elevator pit, the best time to look at it is while it’s leaking. We repair pits from the inside for strata, property managers, builders and building owners across Vancouver, Burnaby, Richmond, Surrey and the Fraser Valley. Learn more about our elevator pit waterproofing and leak repair, then call (778) 686-2221 (Mon–Sat, 8:30 AM–5:00 PM) or book a free inspection.