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PermaSEAL PRO 20P Green Roof Drainage & Storage Membrane 20m²

100% of 100
£149.00 Ex VAT
£178.80 Inc VAT
A high quality green roof membrane that acts as both a drainage layer and large volume water storage membrane as part of a green roof system.
PRO Range

Green Roof Drainage & Storage Membrane – 20mm Cavities

PermaSEAL PRO 20P is the ultimate high quality Green Roof Membrane. Manufactured from HDPE, it acts as an 'all in one' drainage layer and high volume water storage membrane for green roofs. It can be used in both extensive and intensive green roof systems on houses, sheds, garages and larger commercial projects. It is also suitable for walkable and drivable deck paving drainage applications.

The PermaSEAL PRO 20P Green Roof Drainage & Storage Membrane is specially designed with a deep stud -  this aids drainage capabilities and also stores more water to help the green roof grow. PermaSEAL PRO 20P features 20mm cavities that are able to store a large volume of water. This is important to maintaining a successful and healthy green roof. These cavities are protected from soil and other detritus by the built-in geotextile layer. 

Our PermaSEAL PRO green roof storage membrane benefits from an integrated geotextile fabric firmly bonded to the membrane. This prevents slip and compression into the water storage cups. 

This geotextile layer also filters out fines and other particles to ensure your green roof can thrive. This bonded geotextile filter layer also saves time on installation compared with when you have to lay a separate loose geotextile layer.

As a green roof drainage membrane, PermaSEAL PRO 20P is perforated to allow water to pass through to the drainage space below. This prevents too much water accumulating and causing damage to the roots as well as preventing the sedum, grass or vegetation from becoming saturated. 

Uses of PermaSEAL PRO Green Roof membranes

This green roof drainage membrane is suitable for both low pitch and flat green roofs as well as intensive, semi-intensive and extensive systems.  

Typically PermaSEAL 20P Green Roof is used in conjunction with a primary waterproof coating above decks, flat roofs and pitched roofs. As the membrane is perforated, it is also suitable for inverted warm roof applications.

Extensive green roofs are popular for the following structures:

  • House
  • Shed 
  • Garage
  • Conservatory
  • Extension

Benefits of PermaSEAL PRO Green Roof Membrane 

The PermaSEAL PRO 20P is an 'all in one' membrane sheet that covers green roof drainage, water storage and filtering. 

Easy to install

Installation is straightforward. We supply the membrane in 20m² roll sizes - this mean the membrane can be handled easily by one person. This makes it ideal for DIY green roof installation as well as professional installation.

Long Lasting

PermaSEAL PRO 20P Green Roof Membrane is a high quality and long-lasting product. It has a life expectancy equal to the design life of the structure (DIN 9001:2000) and is guaranteed against deterioration for 30 years.

As an inert product, it is highly resistant to water, alkalis, saline solutions and organic acids and is not affected by minerals. It is also resistant to bacteria, fungi, and other small organisms which is important for green roof membranes.

Installing a PermaSEAL PRO Green Roof System

Once a primary waterproofing layer has been applied to the concrete roof deck or screed, and a slip layer if required, you can roll out the green roof membrane across the length of the roof. Cut the membrane to size. 

You can overlap the ends of two rolls of membrane, connecting the cavities. We also sell our PermaSEAL Jointing Tape if you want additional protection. 

For more information refer to our green roof design and construction guide.

Other products in the PermaSEAL green roof system 

Root Barrier & Separation Layer – used as a slip layer/root barrier membrane between the primary waterproofing and PermaSEAL 20P Green Roof.

PermaSEAL PRO MP 2C Flexible Waterproofing Compound – the primary waterproofing applied directly to the concrete roof deck or screed. Requires a scratch coat but no primer.

Permagard – Providing solutions. Inspiring confidence.

It is important that you select the correct green roof membrane to suit your requirements. Our 20P membrane functions as part of PermaSEAL's green roof system. Please contact our technical department if you have any questions. Call us on 0117 982 3282.


  • Easy to install
  • Extra high water retention capacity
  • Manageable roll size / weight for one person
  • Long lasting - guaranteed against deterioration for 30 years
  • High compressive strength
  • Tough and durable


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