• Can be applied to damp substrates
  • Accepts plaster finish directly
  • No need for plugs (no unnecessary penetration of membrane)

For more information call
01403 210204

Drybase Flex

Standards & Accreditations


A watertight low-profile sheet membrane for protection against dampness in walls without the need to drill and install plugs. The membrane is a 1.5 mm thick flexible polypropylene sheet with a fleeced surface on both sides. The two fleeces ensure good adhesion to the wall by means of Drybase Flex Adhesive, as well as the direct application of plaster to the face.

Drybase Flex Adhesive

Drybase Flex Adhesive is a polymer modified cement-based product used to fix Drybase Flex Membrane to walls. It is supplied in powder form ready to be mixed with water, and applied using a suitable trowel.

Drybase Flex Application

  1. Remove surface laitance
    Before Drybase Flex Adhesive can be applied, any structural defects on the substrate must be fixed. Clean the surface of the substrate to ensure maximum bonding of
  2. Mix Drybase Flex Adhesive
    Mix to the ratio 1 part tap water to 3.5 parts Drybase Flex Adhesive by weight (for 10 kg bags, add 2.9 lit
  3. Apply Drybase Flex Adhesive
    Spread the Drybase Flex Adhesive with a suitable trowel over the face of the wall to cover approximately 1 m2 at a time. The preferred adhesive thickness is 1 – 2 mm.
  4. Apply Drybase Flex Membrane
    Offer the Drybase Flex Membrane up to the adhesive on the wall and use a trowel to apply gentle pressure spreading from the centre outwards. Make sure there is a 25 mm gap between the floor surface and the membrane (see the Floor-Wall Junction detailing below). Ensure that full contact is established between the membrane and the adhesive. Using a roller may be more suitable to achieve an even pressure.
    Note: For details such as overlapping joints, corners, doors, and windows, please refer to the detailing diagrams beneath these instruction steps.
  5. Remove excess adhesive and trim the excess membrane
    Remove any excess adhesive with a damp cloth before it sets and trim any excess membrane with an appropriate cutting tool.
  6. Apply a skim coat
    After the adhesive has cured overnight, surface finishes can be applied such as bonding plaster or hardwall plaster; both are suitable for application prior to a skim finish.

Drybase Flex Detailing Diagrams

Overlapping Joints

It is important that joint details prevent the penetration of water. For joining two sections, an overlap is recommended of at least 50 mm width.

Drybase Flex overlapping joint detail

Floor-Wall Junction

Apply Drybase Flex Membrane on top of the Drybase Flex Adhesive, leaving a 25 mm gap between the bottom of the membrane and the floor.

Drybase Flex floor-wall junction detail


Apply Drybase Flex Adhesive up to the wall joint and 100 mm onto the abutting wall. Apply Drybase Flex Membrane up to the wall joint.

Drybase Flex corner detail


When plastering around a window, Drybase Flex Adhesive and Drybase Flex Membrane should both be applied up to and around the window frame and window sill.


Apply both the adhesive and membrane up to the door.

Drybase Flex Membrane Properties

Appearance Membrane with black fleece one side and grey fleece on the other
Material Polypropylene
Thickness 1.5 mm
Size(s) & Packaging 9.6 kg roll
Coverage 1.2 × 15 m
Salt Resistance Excellent (salt bath testing conducted in lab conditions)
Reaction to Fire BS EN 13501 Class F
Water Vapour Resistance >0.5·1012 m2sPa/kg
Tear Resistance >400 N
Storage Dry conditions

Drybase Flex Adhesive Properties

Appearance Grey powder
Density 1.48 g/cm3
Size(s) & Packaging 10 kg bags
Coverage 5 kg/m2 (2 m2 per 10 kg bag)
Storage Dry conditions between 5°C and 30°C
Shelf Life 12 months

For more information call
01403 210204