Vapour Control Layers

Insulation Superstore offers a wide range of vapour control layers, for use on all projects, whether it is a large scale new build, a small scale renovation or a simple DIY installation. Our vapour control layers have been manufactured by a number of different brands, including NOVIA, Pro Clima, Visqueen and more, with each brand continuously undertaking research to ensure their VCL layers provide optimum performance.

If you’re unsure of which vapour control layer you require, the difference between vapour control layers and breather membranes, or why VCL membranes are required, read on. Alternatively, give our team of experts a call on 01752 692206 or use the live chat – they are on hand to offer help, advice and product recommendations. 

What are vapour control layers?

A vapour control layer is a layer of material that prevents the movement of water vapour into the building structure – a build-up of interstitial condensation within buildings can lead to the development of mould, damp and rot – and these can cause structural issues, health issues and more.

How does moisture cause issues within a building?

A build-up of moisture within a building can have serious consequences. Firstly, particularly in timber frame buildings, when condensation occurs, the moisture is absorbed by the timber structure. In masonry buildings, this isn’t a problem, as the moisture is released again when the temperature rises, but in timber frame buildings this can cause rot, which can result in a loss of structural integrity. 

During colder seasons, the level of moisture within the building structure can increase due to driving rain, whilst in warmer seasons, condensation forms on the inside of the building wall due to the higher temperature being on the outside of the wall.

As well as issues within the building, moisture can cause issues related to the health and wellbeing of occupants. Damp, cold housing is the perfect situation for mould growth, and mould can be the cause of respiratory illnesses, mental health issues and asthma - 2.2 million Europeans today have asthma, partly due to their living conditions.

 For more information on how damp and cold homes can cause health issues, economic issues and more, take a look at the Healthier Homes Guide.

How do vapour control layers work?

Vapour control layers have been designed to stop water vapour from condensing and forming surface water via condensation. Condensation is when warm, moist air, or water vapour, rises, and then when it comes into contact with a colder surface, it cools and condenses into a liquid. This tends to happen when warm moist air comes into contact with the insulation layer within a building – when insulation gets damp it becomes much less effective at preventing heat transfer, losing its thermal properties. 

A vapour control layer is typically installed on the warm side of the insulation, to block the warm moist air from entering the roof space.

However, it is important to note that the vapour control layer timber frame membrane must be installed in conjunction with a good ventilation system, and membranes. Good ventilation ensures that no air is left stagnant and within the roofing system, whilst breather membranes are fitted to the outside of the insulation, allowing moisture particles to escape from the inside, whilst preventing rainfall and other weather conditions from causing water ingress.

What is the difference between a vapour control layer and a vapour barrier?

A vapour control layer and a vapour barrier have different features that benefit a building structure. Some buildings require the movement of vapour and air to be completely restricted, whilst in other buildings require some restructured movement of vapour and air to provide some airflow to contribute to the longevity and integrity of the building. This is particularly important in timber frame structures, where air and water vapour needs to be transferred from inside the building to the outside in a controlled way to prevent the timber from becoming damp and rotten. 

A polythene vapour barrier limits the movement of air and water vapour through a membrane, so a vapour control layer is air permeable, or vapour permeable. Comparatively, a vapour barrier prevents any movement of vapour or air occurring through the building, instead of just limiting it to a controlled level. It is important to carefully consider the use of a vapour barrier before installation, as in some cases it could result in a build-up of humidity and condensation within layers of insulation. This could not only lead to mould and damp but also negatively affect the performance of the insulation.

What is the difference between a vapour control layer and a breather membrane?

Although many people use the “vapour control layer” and “breather membrane” interchangeably, they are different products. A breather membrane is installed to the outer side of the insulation to allow water vapour to leave the building fabric, without requiring ventilation – ventilation was traditionally the method of preventing condensation from occurring from water vapour, but studies have suggested that this can reduce the effectiveness of insulation. Breather membranes also prevent rainwater from entering the roof space.

Vapour control payers are fitted on the inner side of the insulation, with its key job being to reduce the water vapour transfer through the building, reducing the risk of condensation forming and causing issues.

Vapour control layers and breather membranes work best when both are installed, so that not only is water vapour encouraged to escape from the inside of the building by the breather membrane, but the amount of potential condensation within the building is greatly reduced due to the vapour barrier insulation reducing vapour transfer. 

Products in Vapour Control Layers:

Showing 1 - 36 of 42 products

Showing 1-36 of 42