UGR 20mm Deck & Wall Drainage Membrane 2m x 10m

High-performance drainage for green roofs and landscaped decks

The two-layer membrane combines a water-impermeable 20mm studded HDPE core with a polypropylene geotextile permanently bonded to its surface. Water passes through the filter fabric into the deep drainage cavity, where it can move freely towards the roof outlets or drainage system.

The geotextile helps prevent soil fines and other small particles from entering and obstructing the drainage space, maintaining effective water movement beneath the green roof or landscaping build-up.

Designed for demanding loads

UGR 20mm Deck & Wall Drainage Membrane has a compressive strength of approximately 240kN/m², equivalent to a pressure resistance of up to approximately 24 tonnes per square metre when correctly installed.

Its stud profile distributes loads across the surface beneath it, making the membrane suitable for correctly designed systems incorporating:

• Intensive green roofs
• Roof gardens
• Deep growing substrates
• Walkable decks and patios
  
• Drivable deck paving
• Hard landscaping
• Landscaped roofs above underground car parks
• Other heavily loaded roof build-ups

The complete structure, surfacing and supporting layers must still be designed for the anticipated loading and traffic.

Fast drainage through a 20mm cavity

The deep studded profile creates approximately 14 litres of open air space per square metre beneath the geotextile.

This provides a water-drainage capacity of approximately 9.28l/(s·m) at 20kPa, helping move excess water away from the planted or paved surface.

The product’s drainage capacity is stated as approximately 30 times higher than the requirement of drainage standard DIN 4095.

Integrated filtration layer

The bonded polypropylene geotextile:

• Allows water to enter the drainage cavity
• Filters soil, substrate fines and other small particles
• Helps prevent blockage of the drainage space
• Resists significant deformation as working loads increase
• Remains securely positioned during installation
• Removes the need for a loose filter fabric directly above the membrane

For horizontal green roof and landscaping applications, the geotextile faces upwards towards the substrate, gravel or overlying construction.

Suitable applications

UGR 20mm Deck & Wall Drainage Membrane can be used for horizontal drainage within:

• Intensive green roofs
• Roof gardens
• Landscaped podiums and decks
• Walkable and drivable paving systems
• Patios over suitable waterproofed structures
• Earth-retaining roofs above underground car parks
• Other hard and soft landscaping build-ups

It may also be installed vertically as a protection and drainage layer over primary external waterproofing on below-ground walls.

Where this membrane fits in a green roof

A typical horizontal build-up may include:

1. Structural roof deck
2. Primary waterproofing and any specified gas or radon barrier
3. Root barrier, where required
4. Protection layer, where specified
5. UGR 20mm Deck & Wall Drainage Membrane
6. Growing substrate, aggregate or specified landscaping build-up
7. Vegetation, paving or another compatible finish

Where separate root protection is required, install UGR Green Roof Root Barrier.

Horizontal installation

The surface to be drained should have a fall of at least 2.2%.

1. Complete the primary waterproofing and any required root barrier or protection layers.
2. Begin at the lowest part of the roof or deck fall.
3. Roll out UGR 20mm Deck & Wall Drainage Membrane with the bonded geotextile facing upwards.
4. Pull back the loose geotextile edge to expose the dimpled membrane.
5. Apply compatible jointing tape or a bead of membrane adhesive between the first and second rows of studs.
6. Position the next roll above the first, overlapping approximately three rows of studs.
7. Press the connection firmly together and return the geotextile over the joint.
8. At perimeter walls, rooflights and other upstands, take the membrane up by at least 150mm or to the upper edge of the finished substrate or infill.
9. Complete the roof with the specified growing substrate, gravel or landscaping build-up.

For jointing adjoining sheets, use UGR Membrane Jointing Tape. Alternatively, where appropriate, consider High Strength Membrane Adhesive.

Vertical below-ground installation

UGR 20mm Deck & Wall Drainage Membrane may also protect and drain external below-ground waterproofing.

The black drainage core is positioned against the waterproofed wall, with the geotextile facing outwards towards the backfill.

For walls below 2m high, the 2m-wide membrane can potentially be installed horizontally without an intermediate lap. On taller walls, it should be cut into vertical sheets.

Adjoining sheets are overlapped so that the geotextile continues over the preceding drainage core. One to three rows of studs can be interlocked to help keep the rolls aligned, with the flat edge flange sealed using compatible tape.

The membrane should connect to a suitably designed and maintainable land drain or French drain at foundation level. The upper edge must be capped to prevent debris and backfill entering the drainage cavity.

Long-lasting and resistant

UGR 20mm Deck & Wall Drainage Membrane is:

• Chemically resistant
• Suitable for temperatures from -30°C to +80°C
• Safe for contact with drinking water
• Fire classified as Class E
• Guaranteed against deterioration for 30 years
• Tested and CE marked to the relevant standard

The membrane is manufactured from virgin HDPE, with a bonded polypropylene geotextile.

Important suitability note

UGR 20mm Deck & Wall Drainage Membrane is a protection and drainage membrane, not a primary waterproofing membrane.

It must be installed above a suitable, fully bonded waterproofing system. For below-ground structures, the complete design should form an appropriate Type A barrier system in accordance with BS 8102:2022.

It is also primarily designed to drain water rather than retain it for vegetation. For a green roof membrane with dedicated water-storage capacity, consider UGR 20mm Storage & Drainage Membrane, UGR 40mm Storage & Drainage Board or UGR 60mm Storage & Drainage Board.