How to Check Cavity Wall Insulation: Guide & Tips

Cavity walls are one of the most popular build types across the UK, totalling around three-quarters of all properties. These wall types consist of an inner and outer leaf, with a cavity space in between that can be filled with insulation material. 

This highly effective method can cut your home’s heat loss by up to 33%, bringing you massive energy bill savings, CO2 cuts, and fostering a cosy home environment. However, you might ask yourself; how do I know if I have cavity wall insulation?

This ultimate guide by GreenMatch UK will show you how to identify cavity wall insulation, how to monitor its health and notice telltale signs of damage before they become a bigger issue.

Want to insulate your cavity walls? GreenMatch UK can be your one-stop solution! Instead of spending endless hours scouring the web for the right bargain, just spend 30 seconds filling out our survey and we’ll send you up to 3 free home-tailored quotes from trustworthy installers in your area. Completely free of charges and obligations. Click below to begin!

The easiest way to know if you have cavity wall insulation is to check your brickwork for drill holes. Wall cavity insulation is installed by drilling small, evenly spaced holes through the outer wall and injecting insulation material into the cavity space. After installation, these small holes are filled with cement to prevent moisture from entering, but can sometimes still be visible. 

In some cases, these small holes might not exist. If you live in a newly built home, or if an installer did a really good job in concealing the marks on your outer wall, checking for drill patterns might not be feasible.

Luckily, there are a few other ways to check whether your cavity walls already contain insulation:

If you know that you do not have cavity walls, you can check some alternatives to cavity wall insulation that are more suited for your home.

Identifying small holes that are evenly spaced along the mortar lines of your exterior brickwork is a telltale sign of cavity wall insulation. These holes will likely already be filled in with cement, but you may still notice their outlines. 

These evenly spaced drill holes in your cavity walls also give you a clue as to what type of insulation material you’re likely to have. In this case, your walls likely contain polystyrene bead insulation or blown mineral wool insulation. 

There are two key documents you can check to get information on your home and its energy efficiency upgrades: your EPC certificate, or your home documentation. 

Every home comes with an EPC, which can also have a record of home efficiency upgrades that have taken place. You can check your EPC documentation for information on cavity wall insulation, or check online through the UK official EPC register by using your address.

Property documents can mention energy efficiency upgrades that have taken place, especially if installed by a registered installer. Most professional cavity wall insulation companies are CIGA certified, coming with a 25-year guarantee on jobs. Property paperwork likely contains details of this guarantee if insulated. 

If your home was built after the 1930s, you're likely living in a cavity wall property. If you’re unsure, you can identify cavity walls by simply looking at your brickwork pattern. 

Cavity wall properties always have an even brick pattern, where all the bricks are laid lengthways. In comparison, solid wall properties have uneven brickwork patterns.

If your home was built after the 1990s, there's a big chance it has cavity wall insulation in place. This is because property regulations began demanding cavity wall insulation for all cavity wall properties around this time.

This doesn’t mean that any cavity wall insulation hasn't been removed or replaced since then but does increase the likelihood that your cavity walls have insulation in place.

If you’re still wondering how to check for cavity wall insulation, you can always hire a professional surveyor to conduct a wall inspection. 

Surveyors and installers use a handy tool called a borescope. This is a cavity wall insulation checker that uses a camera on an extendable beam to check cavity wall insulation through a drilled hole. It can also identify if any insulation in place is in good shape or not. 

A cavity wall inspection can cost anywhere from £150 - £300, but some insulation companies provide free inspections with their cavity wall insulation packages.

Now that you know how to check cavity wall insulation, how can you make sure it works? You may find that your home already has cavity wall insulation in place, but this doesn’t always mean it’s performing as it should. Cavity wall insulation can still be damaged, or even subject to moisture and mould growth. 

There are several telltale signs you can look out for to know whether this might be the case:

If you notice any of these signs, contact a professional installer for a wall inspection. Handling these problems proactively can help you avoid burdensome repair costs and structural home issues down the line. 

Deciding to insulate your cavity walls is just the first step! To avoid a burdensome cavity wall insulation price, choosing the right professional installer is just as important, as this could be the line between decades of comfort and a poor installation with hefty repair bills. 

When looking for installers, make sure to check for these key points:

While it all seems straightforward, researching and vetting installers can take endless hours with no bargain in sight. That’s where GreenMatch UK can save you the effort.

Instead of spending countless hours scouring the web and scheduling phone calls with potential installers, just spend 30 seconds filling out our simple form. In return, we’ll send you up to 3 free home-tailored quotes from trusted installers in our nationwide network at competitive prices. The best part? Our services are completely free and without obligations. Click below to begin!