Waterproofing membrane for basement Floors 20 & 40 sqm

CM20 2x10
Price incl. VAT
(6 items in stock)

Baseline 20 cavity drain membrane is moulded from high density polyethylene (HDPE) and incorporates integral 20mm stand-off studs at 50mm centres to offer exceptionally high drainage capacity.  This high-profile waterproofing membrane is supplied in a choice of 2 x 10m or 2 x 20m rolls, each including a 100mm wide stud-free strip for overlapping sheets.

Our air-gap membranes are robust and durable.  They can be used on floors, walls, vaulted soffits and tunnels in basement waterproofing and other construction and civil engineering applications that require a cavity drain system to combat water seepage.

As a BS 8102: 2009 Type C compliant tanking membrane, Baseline 20 is suitable for waterproofing floors below ground level as part of a system that delivers a Grade 3 dry environment in basements.  The cavity-drain membrane forms part of a sealed waterproof tanking system with provision for disposing of water accumulation using the cavity behind the drainage membrane. The impermeable surface permits direct laying of floors and screeds. 

  Baseline 20 Cavity Drain Membrane   Data
  Material   HDPE
  Sheet Thickness   1mm
  Membrane Height   20mm
  Water Void Capacity   >14.61 l//m²
  Weight   1 Kg/m² 
  Water tightness at 60 kPa   >24 hours
  Working Temperature   -50°C to +80°C
  Softening Temperature   126°C
  Mean Compressive Strength   165 kN/m² 

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Delivery options are only available for delivery to mainland UK (excluding Scottish Highlands, Scottish Islands, Channel Islands, Isle Of Man Northern Ireland and Eire). Delivery to Scottish Highlands, Scottish Islands, Channel Islands, Isle Of Man, Northern Ireland and Eire are limited to 20kg and are available at a Premium rate. Please contact us on or via our help line if delivery is required outside these areas. Alternatively select ‘World-wide Delivery’ and a member of our sales staff will contact you regarding your options and costs.


We offer for the mainland UK , as standard, a FREE delivery service on all orders having a value greater than £200.00 (excluding VAT). For orders having a value less than £200.00 (excluding VAT) a carriage fee of £8.50 + VAT will be levied. Goods will be sent by a national carrier on their 1-2 working day standard service. Customers must understand that delays can always happen while their order is with the courier, for this reason we can not guarantee your order will be with you next day.

It is important that the customer ensures that all the delivery details are correct and that the customer or someone acting for the customer is able to sign for the delivery. Twistfix accept no liability for failed deliveries as a result of incorrect delivery details or the absence of any authorised signatory. Twistfix will attempt delivery to the recipient between the hours of between 8am and 6pm. If no one is available to receive the delivery an attempt may be made to leave the item with a neighbour. Alternatively the carrier may return the item to the sorting office and leave a calling card at the recipient's address to advise of the attempted delivery. It is the responsibility of the customer to arrange to collect the item from the depot or to arrange re-delivery with the carrier. Further information regarding Delivery can be read at our Terms & Conditions.


Items returned and received in their original condition and packaging within 14 days of delivery will be accepted for exchange or refund subject to a 20% restocking fee. You will be responsible for the shipping costs incurred in returning the goods and should ensure the items are adequately insured while in transit to us. You should email to request to return items.

Where the goods are being returned because they are faulty or are not the goods that were ordered then, subject to the goods being returned in re-saleable condition, Twistfix will refund the cost of return shipping. Further information regarding Returns can be read at our Terms & Conditions.