Exterior Solutions
Exterior Waterproofing Membrane
The black spray on most foundations is damp-proofing, not waterproofing. It slows moisture. It was never designed to hold back water under pressure.
Priced by wall length and depth · Free assessment
What you get
- Stops water before it ever contacts the concrete
- Lets us repair the exterior face of the wall while it is exposed
- Includes new footing drainage and free-draining backfill
- The most complete and longest-lived foundation protection available
The coating on your foundation is probably not waterproofing
When your house was built, a crew sprayed the exterior of the foundation with a thin black asphalt emulsion before backfilling. Most homeowners assume that is waterproofing. It is damp-proofing, and the two are not the same thing.
Damp-proofing is a moisture retarder. It slows the capillary movement of soil moisture through concrete. It is applied thin, it cures brittle, it cannot span a crack that opens later, and it is not rated to hold back water standing under pressure. It also takes physical damage during backfill: a single stone dragged down the wall opens a path.
Waterproofing is a different product entirely: an engineered membrane applied at meaningful thickness that stays flexible, bridges minor cracking, and is designed specifically to hold back water under hydrostatic head.
Almost every foundation in Nova Scotia has the first. Very few have the second.
What the full system includes
Exterior waterproofing is the most complete thing you can do for a foundation because it addresses water on the side it is coming from. It is also the only opportunity to work on the exterior face of your wall.
Excavation to the footing. Services are located first. We dig to the top of the footing along the affected walls.
Wall repair with the wall exposed. This is the part that is impossible from inside. Cracks are repaired from the exterior face. Form-tie holes, a chronic leak source in poured walls, are cleaned and sealed. Honeycombing from poor consolidation during the original pour is packed out. Failed parging on block is stripped and re-applied. Once the wall is sound, it is coated.
The membrane. Applied over the full wall height and detailed at the wall-to-footing joint, at every corner, and around every penetration. Detailing is where membranes fail; a perfect field application with a sloppy corner leaks at the corner.
Drainage board. A dimpled sheet over the membrane creates a permanent air gap against the wall. It does two jobs: any water reaching it runs straight down the dimples to the footing drain instead of standing against the wall, and it takes the mechanical abuse of backfill so the membrane does not.
New footing drain. Perforated pipe bedded in clean washed stone, wrapped in filter fabric, sloped continuously to a positive discharge. See exterior weeping tile.
Backfill and grade. Free-draining material placed in lifts, and a final grade that slopes away from the house. Getting the grade right at the end is what stops surface water from collecting against a wall you just spent good money waterproofing.
When exterior is the right call
Exterior work is the stronger system, but it is not always the right recommendation.
It makes sense when the wall itself is deteriorating and needs repair, when there is visible cracking or failing parging outside, when you are already excavating for other work, when the basement is being finished to a high standard, or when interior drainage would not address the actual entry point.
It does not make sense when access is blocked by property lines, a driveway, a foundation-adjacent structure, or mature trees you are not willing to lose; when the water is entering under the slab rather than through the wall; or when the budget is better spent on interior drainage that solves the same problem for less.
We price the option that fits your foundation and your situation, and we will tell you plainly when the cheaper approach is the better one.
Jobs like this
Exterior Waterproofing Membrane in practice
Basement Walkout Entrance, Bridgewater
A code-compliant walkout added to an existing foundation, engineered and permitted, with the drainage that keeps stairwells from flooding.
BedfordExterior Membrane on the Uphill Wall, Bedford
A sloped Bedford lot delivering groundwater to one elevation: treated on that wall only, at a fraction of a full-perimeter cost.
Questions
About exterior waterproofing membrane
What is the difference between damp-proofing and waterproofing?
They are different products for different jobs, and the distinction costs homeowners a great deal of money. Damp-proofing is the thin asphalt-based coating sprayed on most new foundations at construction. It resists soil moisture wicking through concrete, it is thin, brittle, and it cannot bridge a crack or hold back standing water under pressure. Waterproofing is an engineered membrane, applied at real thickness, that remains flexible and forms a continuous barrier capable of holding back water under hydrostatic pressure. Nearly every foundation in Nova Scotia has damp-proofing. Very few have waterproofing.
Do you have to dig up my whole yard?
Only the walls that need it. Water intrusion is often confined to one or two elevations, and we excavate those. It is genuinely invasive on the affected sides (decks, walkways, plantings, and sometimes sections of driveway have to come out and go back), and we tell you exactly what will be disturbed before you sign anything. Where excavation is impossible because of property lines or structures, an interior system is the alternative and we will price that instead.
How long does exterior waterproofing last?
A properly installed membrane with drainage board and a functioning footing drain is designed to outlast the mortgage. The membrane is not exposed to UV or freeze-thaw once backfilled, and the drainage board protects it mechanically during backfill, which is when most membrane damage actually happens. Our waterproofing carries a transferable lifetime warranty.
Is exterior work possible in winter?
Not reliably. Frozen ground is difficult to excavate cleanly, membranes have minimum application temperatures, and backfilling with frozen material means it settles badly when it thaws. We schedule exterior work from spring through late fall. If your basement is actively flooding in February, we can do interior work immediately and book the exterior for spring.
Can I get exterior waterproofing on just one wall?
Yes, and it is common. If the assessment shows water is entering only through the uphill wall, that is the wall to treat. Doing all four when one is the problem is money spent for no additional benefit. The written diagnosis tells you which walls are involved and why.
Further reading
More on exterior waterproofing membrane
Structural Concrete Repairs: Restoring Strength, Not Just Sealing
When a foundation crack is structural rather than cosmetic, and what restoring the wall's load-carrying capacity actually involves. Epoxy, staples and carbon fibre.
The Products That Decide Whether a System Lasts 30 Years or 5
Washed stone, filter fabric, dimple board, membrane and check valves. The unglamorous components that separate a system that lasts from one that silts closed.
What Basement Waterproofing Costs in Halifax
What drives the price of waterproofing a Halifax basement (linear footage, access, foundation type and discharge), and how to compare two quotes properly.
Where we do this work
Exterior Waterproofing Membrane across mainland Nova Scotia
Free assessment
Tell us what you’re seeing.
We’ll come out, diagnose it properly, and give you a written quote. No charge, and no pressure. If a cheaper fix will solve it, that’s what we’ll tell you.
(902) 555-0100