New-Construction Leak Deficiencies: A Builder’s Punch-List Guide to Below-Grade Leaks

The walk-through found water below grade. A damp line along a wall-to-slab joint. A weeping form-tie hole. A wet floor in the elevator pit. Handover is coming, those items are sitting on the deficiency list, and someone has to close them before occupancy.

Construction deficiency leak repair for below-grade concrete is usually done from the inside. Most of these items can be sealed without excavating backfill or opening up finishes, which is what site teams need when the punch list has to move. Here’s what typically shows up, what the GC or consultant needs on file to close each item, and how to sequence the work. When you’re ready for a site look, see our concrete leak repair for stratas and new buildings.

Common below-grade leak deficiencies at handover

New building leak deficiencies below grade often stay hidden until groundwater rises. Concrete that looked dry at earlier inspections can start to weep once the Lower Mainland wet season sets in and the wall is under pressure. The items below are the ones that turn up most often on a handover list.

Cold joints (wall-to-slab and pour joints)

A cold joint is where one pour met another: wall-to-slab, wall-to-wall, or a stop in the middle of a lift. On a walk-through you’ll see a straight damp line, a tide mark, or active seepage along that joint, often at the base of a parkade or foundation wall. The joint is a path through the concrete, and groundwater finds it first.

Form-tie holes

Form ties leave holes through the wall once the forms come off. They’re often patched, but a patch that isn’t watertight will weep once the wall is under pressure. Look for damp circles, rust staining or a drip at regular intervals along the wall — the spacing of the ties. These are among the most common deficiency list concrete leaks, and they’re usually straightforward to seal from the inside.

Pipe and conduit penetrations

Water at a pipe sleeve or conduit where it passes through a wall is a two-material joint, and it belongs on the list. We cover how those entries leak and how they’re sealed in our post on pipe and conduit penetrations in concrete walls.

Cracks in walls and slabs

Shrinkage cracks, settlement cracks and cracks at re-entrant corners show up as damp lines, white mineral deposits or active drips on parkade walls, pit walls and slabs. A crack that only weeps in heavy rain still belongs on the list. That’s when the path is visible, and that’s useful for the repair.

Wet elevator and sump pits

Water in an elevator pit or sump barrel at handover is a common deficiency, and it needs its own look because of the equipment in the pit. We repair elevator pit leaks from the inside; see also our guide to elevator pit waterproofing and our post on pipe entries into sump pits.

What it takes to close a leak deficiency item

Closing a leak item is about a clear record as much as the repair itself. The GC or deficiency consultant usually needs, on file:

• Location. Room, grid line, wall or pit, and which side of the wall.
• Photos during or after rain, dated, showing the path while it’s wet.
• What was done. A short description of the repair at that location.
• A re-check after the next wet spell, to confirm the path is no longer active.

Keep the record simple and consistent across items. What a consultant or owner will accept is their call, not ours. We can photograph the work, walk the item with you after the next rain, and give you a clear description of what was sealed.

Construction deficiency leak repair from the inside

Below-grade deficiency repair is usually a negative-side job: we treat the leak on the inside face of the wall or pit, against the water pressure. Backfill, landscaping and finishes on the outside stay put. That’s why this work can often go ahead after the building is closed in.

The general sequence is the same for a cold joint, a tie hole or a crack. We clean back to sound concrete, stop running water with Krystol Plug where needed, treat the joint with Kryton’s Krystol T1, and use compatible injection where the crack needs it. We’d rather seal the leak while it’s active, because the water shows the path.

For more on the repair itself, see our concrete leak and penetration repair page. We also cover how crystalline waterproofing stops an active leak in a separate post; this one stays on the punch list.

You may also hear about exterior excavation or a new exterior membrane as a way to treat a wall from the outside. Ask us whether it suits your building after a site look.

Sequencing repairs so they don’t hold up occupancy

The rainy season is when these leaks declare themselves. Use that, instead of waiting for a dry stretch that may not arrive before handover.

• Log leaks while they’re wet. Photograph and date each one during or after rain. A dry-day walk-through will miss items that only weep under pressure.
• Book the site look. A free inspection, and a quote from that look, let you put repair into the close-out plan instead of finding it at the last walk-through.
• Clear access before trades close things in. Drywall, storage lockers, bike racks and equipment pads will hide walls and pits. Get the leaks treated, or at least exposed and logged, before those finishes go in.
• Coordinate pit work with the elevator contractor. Elevator pits often need the elevator trade involved, or at least a clear window when the pit is accessible and the equipment can be protected.

None of that comes with a timeline from us. The point is to get the leaks onto the list and in front of a contractor while the walls are still reachable.

Building your deficiency list: a quick below-grade checklist

Walk these areas during or after heavy rain and add every active or stained leak to the list:

• Parkade walls, columns and slab soffits. See our parkade crack and leak repair page.
• Elevator pits and sump pits
• Mechanical and electrical rooms, including pipe and conduit entries
• Storage rooms, bike rooms and locker areas on below-grade levels
• Retaining walls and stairwells that sit below grade

This is a short deficiency-list pass, not a full building inspection. For a broader below-grade walk-through, use our building leak inspection checklist.

Common questions

What are the most common below-grade leak deficiencies in new buildings?

The ones that show up most often on a handover list are cold joints (especially wall-to-slab), form-tie holes, pipe and conduit penetrations, cracks in walls and slabs, and wet elevator or sump pits. They can look dry at earlier inspections, then appear as damp lines, drips or standing water once groundwater rises and the wall is under pressure.

Can a leak deficiency be fixed without excavating?

Often, yes. Negative-side repair treats the leak from the inside face of the wall or pit, so excavation can often be avoided. Every building and every item is different, so the first step is a free site look. We’ll tell you whether an interior repair suits that deficiency, and you can ask us whether any other approach suits your building.

When is the best time to inspect for leak deficiencies?

During or right after heavy rain, when groundwater is up and the path is visible. A dry-day walk-through can miss items that only weep under pressure. Photograph and date what you find, then book a look while the evidence is still there.

What should go on a deficiency list for a below-grade leak?

Record the location (room, grid, wall or pit), dated photos taken while it’s wet, the conditions when it leaks, and a note to re-check after the next wet spell. That file is what the GC or consultant usually needs to track and close the item. Keep the format consistent across the list.

Do leak repairs have to wait until the building is dry?

No. Interior sealing is often done on active leaks, and we’d rather seal while the water is visible, because it shows the path. Waiting for the wall to dry can leave the item open on the list through more of the wet season. A site look will tell you whether the work can proceed.

Book a free deficiency leak inspection

If below-grade leaks are sitting on your punch list, call us for a free inspection. The quote comes from a site look, not a guess. We repair below-grade leak deficiencies from the inside for builders, GCs, deficiency consultants and strata councils taking over new buildings in Vancouver, Burnaby, Richmond, Surrey and the Fraser Valley. See our concrete leak repair for stratas and new buildings page, then call (778) 686-2221 (Mon–Sat, 8:30 AM–5:00 PM) or book a free inspection.