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Vapour Control Layer 125mu - 2.5m x 50m

100% of 100
£53.00 Ex VAT
£63.60 Inc VAT

A 125 micron vapour control layer used to restrict and control the passage of warm, moist air within a property. Protects your structure or roof from interstitial condensation.

VCL Membrane 125mu

This high performance vapour control layer 125mu from Capital Valley Plastics minimises the risk of interstitial condensation within the structure of a building. It acts as a vapour barrier, restricting the passage of warm, moist air within the structure or the roof of a property. In turn, this dramatically reduces the risk of damp and rot developing within the fabric of a building.

A vapour control layer or VCL membrane is an important element of new build construction. This is because the water vapour created by a building’s inhabitants can have a detrimental effect on the structure itself when it condenses within its elements. 

Uses of Vapour Control Layer Membranes

Our high performance VCLs are suitable for wall, floor, and roof constructions. They are normally used with timber frame constructions and situated on the inside of the framework. 

This 125 micron vapour control layer is suitable for use with our range of cavity drain membranes, either above or below ground. It needs to incorporate a mechanically-fixed batten and board system with insulation to the cavity drain membrane.

Installing a Vapour Control Layer

VCLs should be located inside of the warm side of insulation – this is the room side of the structure. If you are using on timber framework, you should fix the VCL with nails. 

When installing a vapour control layer, make sure all laps and edges are fully sealed and taped. VCLs can be sealed using double-sided DPM tape. 

Find out more about how to install a VCL in our guide.


Our expert team are available to offer advice on the use of vapour control layer membranes. If you have questions around which VCL is right for you and the correct installation. Call us on 0117 9823282.


  • Suitable for wall, roof and floor constructions
  • Manufactured in the UK
  • Conveniently sized rolls for easy installation
  • Prevents interstitial condensation
  • 125 micron gauge