Balcony and Deck Waterproofing Vancouver

What Balcony Waterproofing Actually Does

A liquid waterproof membrane is rolled or troweled onto a concrete or plywood deck in layers: a primer that bonds to the prepared surface, an elastomeric base that stretches as the deck moves, a wear coat with aggregate for grip, and a UV-resistant topcoat. It cures into one continuous skin with no seams, so there are no joints for water to find.

On a condo balcony in Vancouver, that skin is the only thing between a winter of rain and the ceiling of the unit or parkade below. Bare concrete is porous. Water works in through hairline cracks, freezes on the odd cold night, and rusts the rebar until the top of the slab spalls off. A coating stops that cycle before it starts. On a wood sundeck the stakes are the same: once water gets into the plywood, it rots the sheathing and the framing under it.

Polyaspartic flake finish for covered balconies and patios FLAKE FINISH

Decks and Balconies We Coat

• Concrete condo and apartment balconies, one unit or a whole building at a time.
• Sundecks and rooftop decks on concrete or plywood, over living space, a carport or a parkade.
• Exterior walkways and breezeways on low-rise and garden apartment buildings.
• Entry landings, stairs and ramps that connect to the deck, finished to match. See our concrete stair coating page.
• Parkade ramps and suspended slabs, covered in detail on the parkade and traffic coating page.

Wood-frame sundecks. We waterproof plywood decks too, with a liquid membrane built for wood. The sheathing has to be sound and sloped, the joints between sheets are reinforced before the membrane goes on, and the flashing at the wall and door has to be right. If the plywood is soft or the framing has rot, that gets repaired first.

Liquid Coating, Flake or Sheet Vinyl?

For most balconies and decks, concrete or plywood, a liquid-applied membrane is the usual choice. It follows the shape of the deck, turns up the wall at the door, and wraps around railing posts without a seam. Here is how the three common options compare.

Covered balconies that stay dry and only need a clean, easy-care finish can take the same flake system we put on patios and exterior slabs, as long as there is no living space below.

Where Vancouver Balconies Let Water In

Most balcony leaks start at a detail, not in the middle of the deck. BC Housing's maintenance bulletin on decks and balconies points to guardrail fasteners and the corners of guard walls as common leak points, and recommends an inspection at least every two years. What we see most often:

1. Ponding. Water that sits after rain means the deck is flat or falls the wrong way. BC Housing's illustrated guide to safe and durable wood decks and balconies recommends at least a 2% slope away from the building.
2. Railing posts. Every post fastened through the top of the deck is a hole in the membrane unless it is sealed properly.
3. Door thresholds. The membrane has to turn up the wall under the door, not stop at the sill.
4. Cracks and spalls. Shrinkage cracks and rusting rebar open the slab to water.
5. A worn wear coat. Planters, barbecues and chair legs grind through the top layer, then weather gets at the membrane.

How We Waterproof a Balcony or Deck

1. Assessment. We check the slope with a level, look at the drains, posts and door sills, and note every crack and spall.
2. Prep. The old coating is removed where it has failed. Concrete is ground to open the surface so the primer can bond (see concrete grinding and floor prep). Plywood is checked for soft spots, fastened down, and the joints between sheets are reinforced.
3. Repairs. Cracks are routed and filled, minor spalls are patched, and low spots are built up so water runs to the edge or the drain. Where rebar is exposed or an edge is breaking up, we flag it for a concrete restoration contractor or engineer first.
4. Details first. Posts, drains, inside corners and the wall-to-deck joint are sealed and reinforced before the field is coated.
5. Membrane. Primer, then the base coat at the thickness the system calls for, turned up the wall at thresholds and walls.
6. Wear coat and grit. Aggregate is broadcast for traction, then locked in with the wear coat.
7. Topcoat. A UV-resistant topcoat in your chosen colour. Return-to-service timing is confirmed in your quote.

Balcony Coatings for Strata Buildings

On a strata job, the coating is the easy part. The planning is what keeps owners onside. We walk the building with the council or manager, group balconies by elevation and access, and give you a schedule you can put in a notice, so residents know which day their balcony is off limits and when furniture can go back.

• One written quote per phase, with a unit list and the repairs noted for each balcony.
• Liability insurance and WorkSafeBC coverage on every crew, with a clearance letter on request.
• Photos of each balcony before and after, for your records and your depreciation report planner.

Balcony membranes are a line item in most depreciation reports. The province explains when stratas need one on its depreciation report requirements page, and how repair duties split between the strata and owners on its division of repair duties page.

Working Around Vancouver Rain

Liquid membranes need a dry slab going in and dry weather while they cure. We test the concrete for moisture before we coat, watch the forecast rather than the calendar, and keep the surface above the dew point by the margin the product's data sheet asks for. In practice most exterior balcony work in the Lower Mainland runs from late spring to early fall. Covered balconies and decks under an overhang can often be done outside that window.

Balcony Waterproofing Cost

Every balcony and deck is quoted after a site visit. The things that move the price:

• How much old coating has to come off, and how well the rest is bonded.
• Cracks, spalls and slope correction needed before the membrane goes down.
• Railing posts, drains and thresholds, which are hand detail work.
• Access: ground level, swing stage, or carrying everything through a unit.
• How many balconies are done at once. Whole-building phases cost less per unit.

You get a written quote that lists the repairs, the system, and the warranty terms before any work starts. GST (5%) is additional.

Where Another Trade Comes First

A coating cannot fix a structural problem. Rotten framing under a wood deck, a slab that has lost its reinforcement, or a balcony that has pulled away from the building needs a structural engineer and the right trade before anyone coats it. If we find that at the assessment, we tell you, and we come back to waterproof once the repair is done.

Balcony and Deck Waterproofing: Frequently Asked Questions

Related Services

• Parkade and traffic coatings for ramps and underground parking.
• Outdoor patio and deck coatings for slabs on the ground.
• Concrete sealing for bare exterior concrete.
• Concrete driveway sealing and coating.
• Commercial epoxy flooring for building common areas.