Waterproofing Basements, Underground Walls and Concrete Structures: A Contractor's Guide to WATstop
Water infiltration is one of the most expensive and persistent problems in construction. Whether it's a leaking basement, moisture in underground walls, rising damp in masonry, or water intrusion in a retaining wall, these issues can lead to structural deterioration, mould growth, damaged finishes and costly repairs.
For contractors and architects, the hard cases are the ones where excavation isn't practical. That is where the approach matters most.
That's where WATstop stands apart.
WATstop is a professional-grade epoxy cement waterproofing system built to resist both positive and negative hydrostatic pressure. It provides long-term protection for basements, underground structures, swimming pools, tanks, tunnels, retaining walls, and concrete surfaces exposed to moisture.
Meet WATstop: Professional Waterproofing Without Major Excavation
WATstop is a tri-component epoxy cement waterproofing system designed for demanding waterproofing applications.
Traditional waterproofing repairs often require excavation around foundations, demolition of existing finishes, and significant disruption to the property.
WATstop takes a different approach.
It can often be applied from the interior side of the structure, helping contractors solve moisture problems without extensive excavation. This reduces labour costs, project timelines, and disruption to building occupants.
The Hidden Cost of Water Infiltration
Many moisture problems begin unnoticed. Over time, water infiltration can lead to:
- Basement leaks
- Rising damp
- Mould and mildew growth
- Cracked coatings and finishes
- Efflorescence and salt deposits
- Structural deterioration
- Costly remediation projects
For below-grade structures, preventing water intrusion is far more affordable than repairing long-term damage.
Why Contractors Choose WATstop
1. Handles Both Positive and Negative Water Pressure
Most waterproofing systems are designed for only one type of pressure.
WATstop withstands:
Positive Hydrostatic Pressure
Water pushing directly against the waterproofed surface.
Negative Hydrostatic Pressure (Counter-Thrust)
Water pressure pushing from the opposite side of the structure.
WATstop resists:
- 9.5 ATM Positive Pressure
- 9.5 ATM Negative Pressure
This makes it ideal for below-grade applications where moisture pressure can come from multiple directions.
2. Waterproofing Without Exterior Excavation
One of WATstop's biggest advantages is its ability to solve many moisture problems from inside the building.
Benefits include:
- Reduced labour costs
- Faster installation
- Less disruption to occupants
- No expensive excavation equipment
- Ideal for renovation projects
The TDS notes it can be applied indoors to avoid demolition and excavation outside.
3. Stops Rising Damp
Rising damp is one of the most challenging moisture issues in older buildings.
WATstop acts as an encapsulant for rising damp and saltpetre, helping contractors restore moisture-damaged structures while protecting them against future deterioration.
This makes it particularly useful for:
- Heritage buildings
- Older masonry structures
- Basement renovations
- Restoration projects
4. Functions as a Vapour Barrier
Waterproofing isn't only about stopping liquid water.
Moisture vapour can also create problems within walls and floors.
WATstop functions as a vapour barrier on cementitious substrates, helping protect buildings from moisture migration and condensation issues.
5. Excellent Adhesion Across Multiple Surfaces
WATstop demonstrates strong adhesion performance on:
- Concrete
- Masonry
- Tuff
- Ceramic tile
- Expanded polystyrene (EPS)
- Polyurethane panels
This versatility makes it suitable for a wide range of construction and restoration applications.
Where Can WATstop Be Used?
One of the reasons contractors choose WATstop is its versatility.
Residential Applications
- Basement walls
- Foundation walls
- Crawl spaces
- Underground garages
Commercial Applications
- Elevator shafts
- Mechanical rooms
- Underground structures
- Commercial foundations
Water Containment Projects
- Swimming pools
- Water tanks
- Reservoirs
- Retaining structures
Restoration Projects
- Rising damp remediation
- Salt-damaged walls
- Historic masonry preservation
The TDS lists walls against the ground, underground rooms, garages, tunnels, lift shafts, swimming pools and tanks as application areas.
Proven Performance Backed by Testing
When specifying waterproofing systems, performance data matters.
The numbers from the TDS:
| Performance Metric | Result |
|---|---|
| Positive Pressure Resistance | 9.5 atm (139.61 psi) |
| Negative Pressure Resistance | 9.5 atm (139.61 psi) |
| Weathering Resistance | 1,680 Hours |
| Estimated service life | About 10 years (indicative, from the 1,680 h ageing test) |
| Water tightness (UNI EN 1928) | Passed at 2 kPa |
| Solvent-Free | Yes |
| Interior & Exterior Applications | Yes |
| Application Temperature | +5°C to +35°C |
WATstop came through 50 freeze-thaw cycles (−15°C to +15°C) unchanged. For Canadian foundations, that is the number to look at.
Where WATstop Is Different
Most waterproofing products handle pressure from one side. WATstop resists positive and negative pressure, works as a vapour barrier, encapsulates rising damp, goes on from the interior, and takes plaster, paint or tile once cured. It is also solvent-free.
Protect Your Next Project with WATstop
Whether you're waterproofing a basement, restoring a moisture-damaged structure, protecting a retaining wall or working below grade on a commercial project, WATstop is built for that work.
Coverage, prep and the full spec are on the WATstop product page. For residential foundations, start with our foundation waterproofing.
