• 1-3 Days Delivery
  • Low Trade Prices
  • Free Technical Advice

PermaSEAL 8 Geodrain Membrane 40m²

£216.50 Ex VAT
£259.80 Inc VAT

An 8mm stud external waterproofing membrane with Geotex, a filter fabric, thermally welded to the studded face. It is used externally below ground in conjunction with a land or French drain to protect new build basements.


Waterproof membrane for external walls - 40m²

PermaSEAL 8 Geodrain is a twin sheet 8mm stud cavity drain membrane for external waterproofing. It features a high quality geotextile filter fabric, thermally welded to the studded face. 

The Geodrain membrane is used externally below ground in conjunction with a land drain or french drain to alleviate any water pressure bearing on the structure. Although PermaSEAL 8 Geodrain is waterproof, it must always be used in combination with a fully bonded primary waterproofing system.

The high quality filter fabric allows water to pass into the cavity created by the 8mm studs. It is designed to not allow fines or sediments to pass into the cavity. Any water entering the cavity immediately de-pressurises and falls down to the perforated pipe (land drain or French drain). The drain is situated below floor level and drains the water away to a suitable drainage point. The filter fabric should continue around the perforated pipe to also protect it from fines and sediments.

PermaSEAL 8 Geodrain External Membrane Installation 

The PermaSEAL Geodrain Membrane is a key component of an external waterproofing system. It is relatively simple to install during new basement construction, especially if you follow the advice we provide below. You can also read our full guide to external waterproofing.

Geodrain External Membrane Diagram:

PermaSEAL 8 Geodrain Installation Diagram


PermaSEAL 8 Geodrain Installation Advice:

  • A fillet should be formed where the basement wall meets the footing with PermaSEAL Fillet Seal.
  • External walls should be waterproofed with a fully bonded waterproofing system. We recommend PermaSEAL PRO MP 2C multi purpose waterproofing prior to the installation of the optional insulation layer then the PermaSEAL 8 Geodrain.
  • PermaSEAL 8 Geodrain should only be fixed above ground level in the top row of studs at 250mm centres. 
  • Place land drain a minimum of 200mm below basement floor level.
  • For a neat finish PermaSEAL Geodrain Capping Strip should be used to cap the top of the membrane at ground level.
  • Use perforated pipe for the land drain or French drain encapsulated in 20mm clean graded aggregates.
  • Protect the PermaSEAL Geodrain external tanking membrane with backfill protection board.
  • Use a well drained backfill, and protect the backfill with Geotextile filter fabric.
  • Slope ground away from retaining wall where possible or drain well.
  • PermaSEAL 8 Geodrain should always be used in conjunction with a land drain or French drain connected to efficient outlets to remove drained water.


Read our guide to external waterproofing for more information.


Permagard - Providing Solutions. Inspiring Confidence

If you want advice around structural waterproofing and how to use external waterproofing membranes then contact our experts. Our technical advisers are available on 0117 982 3282. 

You can also benefit from big savings when you buy our PermaSEAL Geodrain Membranes in bulk

Return to external waterproofing category to browse more products.


  • Resistant to all chemicals normally found in the ground
  • Withstands stresses and movement acting as a slip membrane as the backfill settles
  • Prevents water pressure from bearing against the structure
  • Extremely strong material, minimising the risk of damage when backfilling even when no protection board is used
  • High compressive strength (250kN/m²)
  • Suspended soil particles are filtered out by the geotextile layer
  • Quick and easy to install with a range of ancillary fixing and installation products
Other Products You May Be Interested In