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PermaSEAL 20 Waterproof Floor Membrane 20m²

100% of 100
£103.95 Ex VAT
£124.74 Inc VAT

With a large stud profile of 20mm, PermaSEAL 20 Floor Membrane has the highest drainage capacity in the PermaSEAL range. It has a void volume of 14 litres for each square metre of membrane.


Waterproof Floor Membrane - 20m²

PermaSEAL 20 Floor Membrane is primarily designed as a high capacity floor cavity drainage membrane. The 20mm stud profile creates a large 14 Litre per square metre void, ideal for areas of high levels of water ingress and water movement. It can also be used as a high performance drainage membrane solution for walls or vaulted soffits where extremely high levels of water ingress are a problem. PermaSEAL 20 is also used in tunnels, civil construction and for commercial properties.


The PermaSEAL 20 basement floor membrane is guaranteed against deterioration for 30 years and has a life expectancy of at least 50 year. This basement floor waterproofing membrane is an inert product with high pressure stability. 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.

Installing a Basement Floor Membrane

If a below ground waterproofing system is being installed then the floor membrane should be used with our Drainage Channel and Floordrain perimeter drainage systems. Our innovative PermaSEAL Quick Plug is recommended when fitting PermaSEAL 20 to the wall. 

PermaSEAL BBA approved waterproofing system

Our PermaSEAL waterproofing system has BBA approval, awarded by the UK’s leading building product certification body. Independent, expert-led and trusted by professionals, BBA certificates are a symbol of quality within the construction industry. You can use our PermaSEAL 8 and 20 membranes and related products safe in the knowledge they have been independently tested to ensure the highest quality levels.

Related Resources 

When carrying out basement waterproofing you need to comply with BS8102 Regulations – read our advice post to find out more. Browse more basement waterproofing products.


  • BBA Approved System
  • Suitable for high levels of water ingress
  • High drainage flow rate (12 L / m / second)
  • Guaranteed against deterioration for 30 years
  • Life expectancy of at least 50 years
  • Highly resistant to water, alkalis, saline solutions & organic acids
  • Resistant to bacteria, fungi and other small organisms
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