Water Penetration and Water Vapour Permeability

The control of water in and out of a building is critical to ensure a safe, habitable and comfortable dwelling. Water can be transported in a number of forms and by different transport mechanisms. A tanking or waterproofing product may be designed to completely exclude the transport of water into a building, where as vapour control layer will regulate the transmission of vapour to ensure that a building is breathable and can help to reduce the risk of condensation and mould growth. We test a wide range construction products to assess the ability to resist penetration from water and permeability to water vapour transmission.

Our Key Facilities:

  • Hygrothermal rigs
  • Inverted roof flow rig
  • Sun/rain rigs
  • Water absorption (capillarity) equipment
  • Water diffusion rigs
  • Water pressure rig
  • Water resistance rigs
  • Water vapour transmission equipment
  • Weathertightness (various)

We undertake the following tests on water penetration and water vapour permeability products:

Simulated rainfall

  • Hygrothermal thermal cycling
  • Rainfall with wind driven rain
  • Rain penetration
  • Water resistance
  • Weathertightness

Water under pressure (hydrostatic head)

  • Ponding tests
  • Water permeability
  • Water resistance (hydrostatic head)
  • Watertightness of joints and seams

Vapour transmission

  • Resistance to algal growth and fungal resistance
  • Water vapour permeability and transmission

Water absorption

  • Absorption
  • By diffusion
  • Capillarity


  • Humidity and heat exposure
  • Long term water exposure

Water penetration and vapour permeability testing are relevant to the following product areas:

  • Coatings
  • External Thermal Insulation Composite Systems (ETICS)
  • Highways and Bridge Deck Waterproofing
  • Insulation
  • Roofing and Breather Membranes
  • Tanking and Damp Proofing
  • Vapour Control Membranes
  • Water Resisting Admixtures

We’ll help you find what you’re looking for…