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How Does Cavity Wall Insulation Work?

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Businesses are no longer restricted to large office complexes. Nowadays, businesses are run from homes, small outdoor properties, or multi-use premises. If you own a property for your business, whether that’s your own home or a separate office premise, then it you’ll be acquainted with energy bills. But how could you save money on your energy bills and reduce your carbon footprint?
Using cavity wall insulation in your property is a good way to keep the heat in and, when it’s done properly, it can save you money on your energy bills. In an uninsulated building, about a third of all the heat is lost through the walls. If your property was built from the 1990s onwards, then it will have been made with cavity wall insulation to ensure the heat remains within the four walls. However, if your building is older than that, then there is the chance that you may not have any wall insulation at all.
So, how does cavity wall insulation work and what exactly is it? At Utility Bidder, our mission is to save you time and money on your energy bills. That’s why we’ve put together this helpful guide on what cavity wall insulation is, how it works, if it’s right for your property and how much it costs to install. Plus, the savings you can reap on your energy bills using cavity wall insulation, as well as a few handy tips and tricks from our team of experts.
What is cavity wall insulation and how does it work?
So, what is cavity wall insulation and how does it work? Cavity wall insulation is typically used for preventing heat loss in a building. It is made from a variety of materials and is packed into the gaps between the bricks in the outer wall of your property to prevent heat from leaking out.
A layer of insulation is inserted inside the cavities in the bricks. A specialist company will drill holes into the outside wall and inject the insulation through them. These small holes will typically be around 22mm in size at intervals of 1m around the perimeter of your property. Once the insulation is in, the installer will fill the holes with similar products to the original brickwork, so you’ll barely notice them.
Installing cavity wall insulation is not something you can do yourself. A professional registered company can do the job in around two hours for the average property with easily accessible walls. It shouldn’t make a mess either!

Why do buildings have cavity walls?
So why were buildings built with wall cavities? Well, homes and other buildings made from the 1920s and onwards were made with cavities to prevent rainwater from penetrating through the outer wall to the inside of the property. However, the cavities let heat escape, so you’d be spending extra pennies to make your property warm and cosy this winter.
How do you know if your walls have cavities? Well, there are several ways to check. Firstly, find out when your property was made. If it was in the last 20 years, then there’s a very high chance that you will have cavity wall insulation and you don’t need to worry about anything. However, if was built post-1920, then it’s likely to have cavity walls.
You can also measure the thickness of the wall: if your wall is more than 260mm thick at an outside door or window, then it probably has a cavity. Looking at your brickwork may also give you an indication of whether you have gaps in your walls. If the outer brickwork forms an even pattern with every brick laid lengthways, then they will probably have cavities. However, you will have solid walls if the bricks are in an uneven pattern, with some bricks being laid endways instead. Pre-1920 houses and buildings are more likely to have solid walls and won’t have any cavities.
Some houses and buildings have a completely different type of wall structure altogether. They may be built using a steel or timber frame, or constructed using prefabricated concrete.
Types of cavity wall insulation
There are two different fillings of cavity wall insulation – full fill cavity or partial fill cavity. A professional will be able to determine which filling your property needs. Plus, with so many different types of cavity wall insulation being manufactured, it’s easier than ever to ensure that your property reduces heat loss.
Mineral wool
Mineral wool insulation is the most commonly used wall cavity insulation because it is very easy to use and manipulate. It can be pre-cut to suit individual joist widths, can be packed tightly together with ease and can be effortlessly manoeuvred to slide between the joists.
Beads and granules
Beads and granules trap heat efficiently and create gap-free wall insulation, so it’s another popular choice. Typically, the beads are made from polyester, so they’re a lighter and more cost-effective solution than mineral wool.
Foam
Made from polyurethane, foam insulation has been hailed as the best cavity wall insulation. However, installation is tricky so it’s imperative that you get a certified professional to install it for you as, without expert attention, foam insulation can degrade over time.
Is cavity wall insulation right for your property?
Cavity wall insulation sounds great, doesn’t it? Save money on energy bills and help reduce carbon emissions. Unfortunately, some buildings are not able to have cavity wall insulation. They include properties that are built with solid or stone walls, or are made using prefabricated concentre or steel or timber frames. There are different insulations available for these types of properties.
There are also some other things to consider if you’d like cavity wall insulation:
- Cavities must be at least two inches wide.
- Brickwork or masonry must be in good condition.
- External walls must be accessible. If you have a semi-detached or terraced property, then the installer will need to insert a cavity barrier which can add to costs.
- Internal walls must be dry.
- Your property must be less than 12 metres high.
- Walls are not exposed to driving rain.
- Your building is not at risk of flooding.
Even if cavity wall insulation is not right for your property, there are other ways of cutting energy costs. Instead of insulating the walls, you could instead insulate your loft. Invest in double or even triple glazing to reduce your heating bill, but also noise pollution. Plus, there’s always using an energy broker who will search the market for the best gas and electricity prices for you.
Cavity wall insulation cost and savings
Installing cavity wall insulation can be expensive and will vary depending on the size of your property. According to Saving Energy UK, homes and businesses can reduce their energy bills by £250 per year.
Plus, you will lower your carbon emissions by around 680kg per year, which is equivalent to planting 11 trees. How brilliant is that? This will help your business improve their green credentials. If you’d like to take your carbon savings one step further, try using green energy providers for your gas and electricity.
That concludes our guide on cavity wall insulation for businesses. We hope we’ve answered your questions, like how does cavity wall insulation work and what are the different types of insulation. We hope we’ve helped you decide on how to save money on your heating bills. Fancy reducing energy bills your even further? Talk to one of our friendly expert team who will help you save money on your utility bills.
Frequently asked questions
The energy regulator, Ofgem, will implement a SoLR or “supplier of last resort” if your supplier ceased business.
No, if your supplier ceased business, your supply will not be cut off. This is because you will be given a SoLR or “supplier of last resort” to ensure you have a continuous supply of gas and electricity. Other suppliers will bid to replace the contracts of businesses that have ceased trading and Ofgem will try to get the best possible deal for the customer in these circumstances.
Ofgem will be working on finding your new supplier as quickly as possible. This will be announced on their website within a few days.
Your business contract will now be void and you will immediately be put on an “out of contract” rate which may result in your bills increasing. This will only be the case until a new tariff is agreed.
In regards to domestic customers, the protection of funds paid by non-domestic customers into their accounts “cannot be guaranteed”. Find out more information here.
Depending on your new supplier, you will still need to pay the debt to your new supplier if they have agreed to take on customer debts owed to your old supplier. If this is not the case, you will need to set up a payment plan with your old supplier’s administrators that will get in touch with you.
Businesses that use a smart meter will be appointed a SoLR and will still have access to a continuous supply. Similarly, to traditional meters, Ofgem will quickly find a suitable supplier for the circumstances. If a supplier is appointed but they can’t operate your smart meter in smart mode, it will work as a traditional meter for that time.
Ofgem advises that you should not cancel your direct debit as your new supplier will get in touch to provide further information on direct debit arrangements.
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