What is a vapour barrier and when is it needed?

One of the purposes of carpeting or flooring is to help insulate homes, and in areas of the UK such as Chester, Wrexham or North Wales, where temperatures can vary wildly, insulation to help keep heat in is very important. One part of this process that is crucial but not always understood is the role of vapour barriers.

What are vapour barriers?

Before the chosen floor material is put in place, whether it is carpeting or something like vinyl flooring, wood or laminate, the floors of a house must have a layer of insulation put down. This is usually screed, polyurethane foam or boards. Insulation helps to stop heat escaping from the rooms of a house or flat, but warm rooms create vapour that turns to moisture, which is referred to as condensation.

A vapour barrier is a piece of material that is designed to prevent this moisture from getting through into your home’s insulation. If such a barrier is not present, there will be nothing to prevent these drops of condensation from penetrating into the material used to insulate the rooms. The water will cause the insulation to rot and can even spread to damage the flooring or carpets eventually. The material that is most commonly used to create a vapour barrier is polythene or some other form of plastic foil. This should have a thickness of 0.2 millimetres at the absolute minimum.

When is a vapour barrier required?

Vapour barriers should be installed as a matter of course in every room of a home or other building that is being insulated. The ideal time for them to be put in place is when the structure is being built, rather than later, when furnishings such as carpets or flooring are being added. The task of installing one once the actual construction has been completed will be harder, more disruptive and time consuming.

The only situation where a vapour barrier will not be needed is if the material chosen for insulation purposes already comes with its own layer of vapour resistance. Should that be the case with your home or commercial space, it does not mean you can forget about the problems caused by condensation.

Something that is known as vapour barrier tape should be used in this sort of situation, as it will act to close up any gaps within the insulation, as well as the seams. The parts of a building that are most vulnerable to damage from vapour turning to drops of water are its ceilings, and these should be the priority if you are looking to install vapour barriers.

However, if the building in question is a house, then the bathroom and kitchen should be next on the list. These are the other areas of the home that are particularly at risk of damp and the damage that it can lead to.

If you want further advice about vapour barriers and whether they are something you need, speak to a specialist flooring company.