Best Basement Waterproofing System

Basement waterproofing systems overview — best practice with Wykamol 

1. What is basement waterproofing?

Basement waterproofing manages water and moisture below ground to achieve a targeted internal environment. Solutions range from barrier coatings that resist water ingress to drained systems that collect and discharge water from behind new internal finishes.

2. Performance grades (design target)

• Grade 1: Basic utility. Some dampness acceptable.
• Grade 2: Better utility. No visible water; moisture tolerances limited.
• Grade 3: Habitable/dry. No dampness acceptable under normal service conditions.

The chosen system must be designed to meet the required grade for the space (e.g., storage vs. living accommodation).

3. System types (A, B, C)

• Type A — Barrier/Tanking: A coating or membrane forms a barrier on the structure to resist water ingress.
• Type B — Structurally Integral: Waterproofing is built into the structure (e.g., watertight concrete) at the design stage.
• Type C — Drained Cavity: Water that reaches the structure is controlled within a cavity and discharged via channels to a sump and pump.

4. What is the “best” system?

The best solution is the one that meets the required grade with acceptable risk. In many refurbishments and change-of-use scenarios, designers favour a combined approach—often a Type C drained cavity system as the core, sometimes paired with Type A barrier measures on key surfaces to reduce ingress and improve resilience.

5. Wykamol product routes at a glance

• Type C (drained cavity): Wykamol CM8 / CM20 membranes, perimeter drainage channel, sump & pump kit, sealing tapes/ropes, plugs and profiles.
• Type A (barrier/tanking): Wykamol cementitious tanking slurry and compatible primers/ancillaries.
• Ancillary control: Anti-mould treatments, ventilation measures, and finishing systems compatible with below-ground environments.

6. Type C drained cavity — typical components

• Wall membrane: Wykamol CM8 or CM20, fixed with appropriate plugs and sealing washers; joints sealed with tapes/rope.
• Floor membrane: Wykamol CM8/CM20 studs-down with sealed joints and perimeter upstand.
• Perimeter channel: Drainage channel set at wall-floor junction with access/flush points.
• Sump & pump: Chamber with submersible pump(s), non-return valve and discharge to a compliant outfall; alarm/monitoring as specified.
• Finishes: Independent studs/linings or floating floors; vapour-open finishes where appropriate.

7. When to add Type A tanking

• Areas of anticipated higher ingress (e.g., local defects, retaining walls under heavy exposure).
• To reduce the water load reaching the Type C system and improve overall robustness.
• Use a compatible Wykamol cementitious tanking slurry on prepared substrates, following product data sheets.

8. Illustrative sequence — Type C with optional Type A

1. Survey & design intent: Confirm target grade, head of water, loading, and routes for discharge and maintenance.
2. Defect repairs: Address cracks, joints, leaks, and service penetrations. Clean and prepare substrates.
3. Optional Type A: Apply Wykamol tanking slurry to designated walls/floor areas; allow to cure per guidance.
4. Perimeter channel: Set level, provide access points; connect to sump chamber.
5. Floor membrane: Lay CM8/CM20 studs-down with sealed joints and perimeter upstand.
6. Wall membrane: Fix CM8/CM20 to walls; seal laps and interfaces to the floor upstand/channel.
7. Sump & pump: Install chamber, pump(s), non-return valve and discharge pipework; commission by a competent person.
8. Finishes: Install independent lining system and floor build-up. Maintain gaps and avoid bridging.
9. Commissioning: Water test the channel and pump function; record levels and set alarms/monitoring.

Note: This is an overview only. Always follow current product data sheets and project-specific design.

9. Ventilation & internal environment

Below-ground spaces benefit from controlled ventilation to manage humidity and minimise condensation on finished surfaces. Coordinate ventilation strategy with heating and insulation to protect finishes and air quality.

10. Maintenance & resilience

• Access points: Keep channel inspection/flush points accessible; implement a service schedule.
• Pumps: Test periodically; consider duty/assist or backup power where risk/usage warrants it.
• Records: Keep commissioning data, alarm settings and maintenance logs on site.

11. Choosing your system — quick guide

• Habitable conversion/refurb: Type C core system (CM8/CM20 + channel + sump & pump) often preferred; add Type A locally if risk warrants.
• New build with watertight concrete: Type B may form the primary resistance, frequently combined with Type C for manageability and serviceability.
• High risk sites: Combined protection (e.g., A + C, or B + C) improves redundancy and maintenance options.

12. Wykamol product checklist

• CM8 / CM20 membranes (walls and floors)
• Membrane plugs, sealing washers, tapes and sealing rope
• Perimeter drainage channel with access/flush points
• Black sump & pump kit, non-return valve, discharge fittings, alarms/monitoring
• Cementitious tanking slurry (where barrier measures are specified)
• Compatible primers/cleaners and finishing systems

13. Product availability

All components referenced in this guide—Wykamol membranes (CM8/CM20), perimeter channel, sump & pump kits, plugs, tapes, sealing rope, and cementitious tanking slurry—are available directly from Clever Shield Coatings. Use the site search bar or browse our product categories to find what you need.