RIW R20 Cavity Drain 2m x 20m

RIW Cavity Drain R20 Heavy Duty Basement Drainage Membrane

RIW Cavity Drain R20 is a heavy-duty Type C cavity drainage membrane manufactured from 1.0mm virgin high-density polyethylene (HDPE). Featuring a robust 20mm stud profile, it creates a high-capacity drainage cavity that safely collects and channels groundwater to a suitable drainage system, providing dependable waterproofing protection for basements, retaining walls and below-ground structures. Designed for projects requiring increased drainage performance, it is suitable for installation onto concrete, masonry and piled walls, including damp substrates.

Designed in accordance with BS 8102 Type C waterproofing principles, Cavity Drain R20 provides effective protection for Grade 1, Grade 2 and Grade 3 basements when installed as part of a fully maintainable drainage system. Its large stud profile delivers exceptional drainage capacity while maintaining excellent compressive strength and long-term durability. The membrane can also be incorporated alongside Type A or Type B waterproofing systems to create combined waterproofing protection where required.

Key Benefits

• Heavy-duty Type C cavity drainage membrane
• Virgin HDPE construction
• Large 20mm stud profile
• Very high drainage capacity
• High compressive strength
• Suitable for walls and floors
• Can be installed onto wet substrates
• Resistant to chemicals and contaminants
• Suitable for concrete, masonry and piled walls
• Long service life
• Easy to install
• Compatible with Type A and Type B waterproofing systems
• BBA Approved
• CE Marked to EN 13967

Applications

• Basement waterproofing
• Cellar conversions
• Below-ground structures
• Retaining walls
• Piled walls
• Concrete walls
• Masonry walls
• Basement floors
• Type C drained waterproofing systems
• Structural waterproofing

Technical Information

• Product Type: HDPE cavity drainage membrane
• Material: Virgin high-density polyethylene
• Colour: Brown
• Thickness: 1.0mm
• Stud Height: 20mm
• Roll Size: 2m × 20m
• Coverage per Roll: 40m²
• Weight: 0.95kg/m²
• Maximum Drainage Capacity: 10 litres/sec/metre
• Maximum Compressive Strength: 150kN/m²
• Working Temperature: -30°C to +80°C
• Lap Width: 100mm (2 stud overlap)
• Certification: BBA Certificate No. 05/4232
• Standard: EN 13967

Frequently Asked Questions

What is RIW Cavity Drain R20 used for?

It is a heavy-duty Type C cavity drainage membrane designed to collect and channel groundwater from below-ground walls and floors into a maintainable drainage system.

What is the difference between R20 and R7?

Cavity Drain R20 features a 20mm stud profile and offers a significantly higher drainage capacity than R7, making it ideal where greater water management is required.

Can it be used on floors?

Yes. R20 is designed for both floor and wall applications and is particularly suited to basement floor waterproofing systems.

Can it be installed onto damp substrates?

Yes. It can be installed onto damp concrete, masonry and piled wall substrates.

Is RIW Cavity Drain R20 certified?

Yes. It is BBA Approved and CE Marked to EN 13967 for use as a cavity drainage membrane.

Downloads

Data Sheet