UGR 120g Green Roof Filter Layer 1.5m x 100m

Keep your green roof drainage layer flowing freely

UGR 120g Green Roof Filter Layer 1.5m x 100m is a durable polypropylene geotextile installed between the drainage membrane and growing substrate in a green roof system.

The filter fabric allows water to pass through freely while preventing substrate fines, soil and other small particles from entering and clogging the drainage cavities below. This helps preserve the drainage performance of the system and protects the water-storage spaces within the membrane.

It is particularly suited for use above drainage and storage membranes that do not have their own bonded filter layer.

Tough, permeable and easy to install

UGR 120g Green Roof Filter Layer combines high water permeability with the strength needed for use beneath green roof growing media. Key benefits include:

• High tear and puncture resistance
• Tough and durable polypropylene construction
• Water permeability of 77l/(m²·s)
• Recyclable material
• UV-stable construction
• Conforms to GRO performance requirements for a filter layer
• Large 1.5m x 100m roll covering 150m²

Its 80μm opening size helps filter fine particles while maintaining water flow and fast drainage through the roof build-up.

Where the filter layer fits in the system

A typical intensive green roof build-up may include:

1. Structural roof deck
2. Primary waterproofing layer
3. Root barrier
4. Protection fleece
5. Green roof drainage and storage membrane
6. UGR 120g Green Roof Filter Layer
7. Growing substrate
8. Vegetation

UGR 120g Green Roof Filter Layer is designed for use above products including the UGR 40mm and UGR 60mm green roof storage and drainage boards.

Installing the green roof filter layer

Install the filter fabric after the drainage membrane has been correctly positioned.

1. Roll the filter layer out across the drainage membrane.
2. Cut the fabric to fit the roof layout where required.
3. Overlap adjoining sections by at least 150mm.
4. Do not take the filter layer across the top of drainage outlets.
5. At roof edges, turn the fabric upwards where needed to separate the growing substrate from a pebble or gravel border.
6. Begin applying the growing substrate along the seams of the filter fabric.
7. Continue adding the substrate while keeping the fabric taut and correctly positioned.

Applying the growing medium along the seams first helps prevent the geotextile from moving or sinking into the cavities of the drainage membrane. Turning the filter layer upwards at perimeter details can also stop substrate fines from contaminating adjacent pebble borders.

Also suitable for land drains

The geotextile can also be used as a filtration layer around land drains in suitable external groundworks and waterproofing applications.

In this type of installation, the drainage pipe and surrounding free-draining stone are enclosed by the filter fabric. This helps stop soil fines from entering the aggregate and reducing the effectiveness of the drainage system.

Durability and exposure

The product has a stated minimum durability of 25 years when used within the conditions specified in the technical data.

To achieve this stated durability, the fabric should be covered or backfilled within 14 days of installation. The durability information applies in natural soils with a pH between 4 and 9 and soil temperatures of no more than 25°C.

Important suitability note

UGR 120g Green Roof Filter Layer is not a drainage, water-storage or waterproofing membrane. It must be installed above an appropriate drainage layer, such as UGR 40mm or UGR 60mm Storage & Drainage Board, and should never be laid across drainage outlets.

The separate fabric is not normally required directly above the roll versions of UGR 20mm or UGR 25mm Storage & Drainage Membrane because those products already incorporate a bonded geotextile filter layer — see the UGR 20mm and UGR 25mm green roof storage and drainage membranes.