CM3 Membrane 2m x 20m for Basements

Clever Shield CM3 Cavity Drain Membrane – Reliable Type C Basement Waterproofing

Protect your property from moisture ingress with the Clever Shield CM3 Waterproofing Membrane — a BBA-certified Type C cavity drain system designed to deliver dry, habitable spaces in line with BS 8102:2009.

Ideal for both basement walls and floors, CM3 effectively manages groundwater by directing it into a controlled drainage system, making it a trusted solution for residential and commercial waterproofing projects.

Efficient Waterproofing Made Simple

• Type C Waterproofing System – Fully compliant with BS 8102:2009
• BBA Certified (18/5595) – Proven performance and reliability
• Quick & Easy Installation – Minimal surface preparation required
• Immediate Finishing – No drying time before redecoration
• Flexible Application – Suitable for walls and floors
• Dry Lining Compatible – Works with timber battens & metal systems
• Seamless Around Openings – Easily shaped around doors, windows & services
• Highly Durable – Resistant to water, salts, roots & contaminants
• Temperature Resistant – Performs in all site conditions

Designed for Long-Term Moisture Control

The CM3 membrane creates a controlled drainage cavity, allowing water to move safely behind the structure and into perimeter drainage channels or sump systems—preventing internal damp and damage.

Perfect for:

• Basement and cellar waterproofing
• Internal wall and floor applications
• Damp-proofing projects
• Residential & commercial buildings
• Retrofit and new build waterproofing

Product Specifications

• Material: High-density polyethylene (HDPE)
• Application: Internal walls & floors (below ground)
• Installation: Mechanical fixing with sealed joints
• Roll Sizes:
  • 2m x 20m (40m² coverage | approx. 20kg)
  • 1m x 20m (20m² coverage | approx. 10kg)

Compatible Waterproofing System Components

For optimal results, install as part of a complete system including:

• Drainage channels
• Sump pump systems
• Fixing plugs & sealing tapes
• Internal dry lining or floor finishes

This ensures a maintainable, compliant waterproofing solution for long-term protection.

Built for Conversions & Damp Environments

Whether you're upgrading a damp basement or waterproofing a new space, CM3 provides a cost-effective, reliable solution for creating dry, usable environments.

Frequently Asked Questions

What is a Type C cavity drain membrane?

A Type C system manages water by allowing it to enter a drainage cavity and safely channel it away, rather than blocking it.

Is Clever Shield CM3 BBA certified?

Yes, it is fully BBA certified (18/5595), ensuring compliance with UK waterproofing standards.

Can CM3 be used on both walls and floors?

Yes, it is designed for both vertical and horizontal applications, making it highly versatile.

Does the surface need to be dry before installation?

No. CM3 is designed for damp environments and does not require a dry substrate.

Is it suitable for basement conversions?

Yes, it is ideal for converting basements into dry, habitable living or storage spaces.

BBA

BBA Certification Clever Shield CM3 Cavity Drain Membrane 18 5595

Performance

Declaration Of Performance CM3 Cavity Drain Membrane WPDOP01 2019 08

TDS

CM3 CDM Data Sheet