Vapour Control Layers

Novia offer a vast range of vapour control layers. Each membrane has its own unique characteristics. Although we can offer advice over which one to use, the final decision must rest with the end user.

Vapour Control Layers (VCLs) are used to manage the transition through the building envelope of naturally occurring moisture vapour, which is produced by general building use. Our range of VCL membranes are formulated with a wide variety of construction designs in mind, delivering the most suitable product for specific solutions for various applications and requirements.

VCLs vary greatly in terms of size, construction, performance and price. Novia can guide customers through the process of choosing their own particular requirements. A wrongly specified VCL that does not fully consider the intended building use may produce unwanted results. Choosing the correct vapour control membrane for your application is key to any insulated building construction, be it timber frame, steel frame or any other style.

The passage of moisture through a building envelope needs to be managed in order to limit unwanted and damaging precipitation or condensation within the interstitial layer. This would occur over the winter in the UK as heavily moisture-laden warm air cooled, due to the typical 20c to 25c temperature difference between the internal and external environmental conditions. As cool air can hold much less moisture, warm air that already has a high humidity will release moisture into the atmosphere in the form of water droplets. This water will damage the internal structures of the building over the long term, and reduce the thermal performance of the insulation.

As little as 3% moisture deposit can reduce the stated thermal performance of some types of insulation by 30% or more. Used in conjunction with external breather membranes, vapour control layers should always be situated on the warm side, or the inside of any insulation, in order to manage the amount of damaging condensation reaching the building's insulation layer and internal components, and just as importantly these days, to reduce convection heat losses, by providing a sealed and air-tight barrier.

For vapour control layers suitable for use in constructions over 18m in height, please see the Novia VC4000 FR Reflective for more details.

All Novia Vapour Control Layers have the relevant UKCA and CE Approvals as required. Please see more information on the individual product pages.

Using Tapes with Novia Vapour Control Layers

Novia Vapour Control Layers are sealed using one of our double-sided butyl tapes, using a minimum overlap of 150mm. A lap-seal is then applied on top using either one of the foil tapes or metallised BOPP tape. The wider the tape used, then the stronger the seal will be, so choose a tape based on your own particular application and budget.

We also suggest that in order to improve overall airtightness, double-sided butyl tape is pre applied to any studs or timbers at the points where fixing is to be made. By preparing the fixing point in this way, when staples etc are applied to either the membrane itself or the final wall covering such as plasterboard, then the achieved seal will be far better. 

For difficult areas to seal with tapes, or for additional support in certain applications, Novia AirSeal 310 is also available. Novia AirSeal 310 FR offers the same support for use in fire rated installations.

Available Products

Novia stock a wide variety of grades and sizes of VCLs and will have one to suit your needs, including reflective grades, which can improve the achieved μ and R values of a given construction. Please click on individual products for further details.

We also offer products are suitable for use as insulation facings. When used on suitable insulation materials these membranes provide a range of benefits such as enhanced vapour, fire and reflective insulation performance.

Our vapour control layers are available for specification via NBS Chorus and NBS Source software.