18th Nov 2022 -

Cavity wall insulation is designed to be a long-lasting solution that can be installed and left in place for a lifetime. Whether using solid cavity wall insulation within the construction process or adding blown-in insulation to an existing cavity wall, you will be looking at a solution that can last for as long as your building. You should be able to establish the date of any pre-installed insulation through records, allowing you to keep track of the status of your cavity wall insulation. In this guide from Building Materials Nationwide, we’ll cover all information needed

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How Long Does Each Type of Cavity Wall Insulation Last?

As we already covered, you’ll be able to insulate your pre-built cavity walls with either blown mineral fibre, polystyrene beads, or polyurethane foam insulation. If building a new property you’ll have a variety of solid options, like insulation batts and boards, with a variety of specialist products available. For blown-in insulation like expanded foam, the lifetime of the insulation is intended to be the same as the building. Unless damage occurs to it, all blown-in types of cavity wall insulation should last for up to a century.

For other insulation methods used during the construction process, the numbers should be similar, lasting up to a hundred years. An exception to this is fibreglass batts, which can start to show wear after 15 to 20 years. When looking for an insulating material for new cavity walls, you should choose a product that will offer strong performance over a lifetime.

How to Check if Your Home Already has Cavity Wall Insulation

If you are thinking of insulating the cavity walls of a home, it’s worth first establishing whether or not the walls are currently insulated, and if so how long they have been insulated. If your house was built after the 1920s then it is likely to have cavity walls, but insulting cavity walls during construction has only become an established practice in recent decades. If you have bought an older house in recent years there is a possibility that it has already been insulated.

The best way to establish this is to check if it is mentioned in any of the documents or surveys done when purchasing the house. Recent changes to a house should be mentioned within the documentation. If this information is available then you will be able to estimate the lifespan of your cavity wall insulation based on when it was installed. You can also check the energy performance certificate of your home online through www.EPCRegister.com, where houses can be identified to contain a “Filled Cavity” or an “Assumed” cavity filler.

If this information is not clarified through documentation, another option is to have your cavity walls examined. Professional surveyors will be able to drill a small hole through the mortar of your outside wall and feed a small camera called a borescope into it. Not only will this establish whether your cavity wall is already insulated, it will also allow you to check the condition of an empty cavity wall, allowing you to plan for insulation if it meets the British Standards for cavity wall insulation. The hole can be easily refilled to give an imperceptible finish.

What Cavity Wall Insulation Problems Can Arise Over Time?

How long cavity wall insulation lasts can depend on the quality of your outside walls and the location of the building. If moisture gets through to your cavity this can damage the insulation and cause issues such as damp patches inside the house. Another cause of damage is the removal of part of the wall, which can cause loose-fill insulation to spill out. In the case of dampness, the insulation may need to be removed and replaced. For underfilled cavities, the loose-fill insulation can be topped up, though this is expensive.

The Importance of a Guarantee

You can ensure the longevity of your cavity wall insulation by getting a guarantee for the installation. Reputable cavity wall insulation installers will offer guarantees of up to 25 years on their work, ensuring that the long-term stability of your energy-saving cavity walls will be covered by them. When looking to have cavity wall insulation installed, an expert installer will offer you a guarantee of how long it will last. CIGA, the Cavity Insulation Guarantee Agency, have a recommended list of suppliers and can cover guarantees should an installer have gone out of business.

Can Cavity Wall Insulation be Topped Up?

As long as the insulation within your cavity wall isn’t damaged, then it can be topped up. This can be a difficult process, and unless there has been severe damage it is unlikely to offer enough of a benefit to your levels of heat loss to justify the price. In cases where the cavity wall insulation is damaged, such as damp EPS beads, it will need to be removed and replaced, providing your walls are suitable for insulating. If your walls are unsuitable for insulation, you’ll have to use the options for solid walls, covered in our guides to insulating internal walls and external walls.

Our Range of Quality Cavity Insulation

To find out if your building is suitable for blown or solid insulation, contact the experts at Building Materials Nationwide today by submitting the form below. Our team of advisors have the knowledge to guide you in choosing the ideal cavity wall insulation and accredited installers to get the job done right.

For our customers in the trades, we offer trade accounts. Sign up for a trade account today to get access to discounted insulation and our network of certified installers. Managing the job through Building Materials Nationwide ensures that your cavity wall project goes smoothly from start to finish.

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