Lower your heating bills with Cavity Wall insulation

Cavity Wall insulation can make a big difference to your energy bills, as well as improving your home’s warmth and comfort. It can effectively stop as much as 33% of a home’s heat from leaking out through the walls2.

How does Cavity Wall insulation work?

Cavity Wall insulation material is expertly installed into the gap or cavity between the two layers of brick that make up the outside walls of a property.

Once installed, Cavity Wall insulation goes to work straight away, keeping in the warmth and lowering the home’s energy bills.

Ask us for an ‘inside and out’ survey

Not sure if your home has cavity walls? Its age is a big clue: if it dates from some time after the 1920s, it was probably built with cavity walls. We can check how your home is constructed at a no-obligation home energy assessment.

A professional survey is essential, as it will confirm if Cavity Wall insulation is right for your home. Our expert will survey the condition of the walls and brickwork inside and out, and assess the guttering and the windows. They’ll also drill a few small holes on the outside walls to check inside the cavity with a borescope. This makes sure it’s clear of rubble or old insulation material, and also helps to size up the cavity. (The holes are sealed up neatly afterwards).

What does it cost?

Each home is unique, so we can’t give you an estimate without seeing the size and type of property.

Once our surveyor has accurately measured the wall areas they can give you a clear, fixed quote for the work, including additional essentials such as vents. You’ll also get an estimated timescale for the installation.

Insulation grants and funding

Our surveyor can also let you know if you qualify for any funding towards the cost of installing Cavity Wall insulation. This is available for certain households through the government-backed ECO (Energy Company Obligation) scheme. Take a look at ECO grants for details of who could qualify.

Party Wall insulation

If your home shares an external wall with another property we can offer specialised Party Wall Cavity insulation. This helps to reduce heat loss from the shared or dividing walls between properties. It’s an ideal solution for semi-detached or linked buildings.

We’re recommended installers

We’re one of the leading Cavity Wall insulation installers in the south of England, with over 40 years of experience. All of our Cavity Wall insulation products are BBA-approved, and we provide a 25-year guarantee for workmanship.

Get in touch to find out more, or call our friendly team on 0800 526 023.

What happens at a Cavity Wall installation?


  • All work takes place outside your property. Our professional and polite installers will work cleanly and efficiently.
  • We keep disruption to your home life to a minimum. Installation can take as little as half a day.
  • We use a specialised machine to install the specified insulating material into the wall space/cavity. Depending on your survey, this could be fibre, wool or beads.
  • The technician drills holes in a set pattern on the outer walls to pump or blow the insulation material inside the wall cavity. We drill as few holes as possible, just enough to ensure that the entire wall cavity is filled effectively.
  • There is likely to be mortar dust from the drilling. The installers will do their best to clear this away, but if the day is wet or windy please understand the difficulty in removing all of this.
  • We will ensure that wall vents for air flow, open fires or boilers will not be blocked by insulation material. If we need to add more vents for safety we will let you know.
  • Once the wall cavity is filled, the technician will seal all the holes with matching mortar and ‘make good’. Many of our customers say they can’t see where the work was done.
  • All installations are carried out by experienced InstaGroup accredited technicians who meet high standards of workmanship. We use only BBA-approved products.

Your assurance of quality

Our Cavity Wall installations come with a 25-year guarantee issued by the Cavity Wall Insulation Guarantee Agency (CIGA)
Party Wall insulation – BBA certificate number 16/5303
Cavity White Wool insulation– BBA certificate number 89/2294
Cavity InstaBead White insulation – BBA certificate number 15/5258

bba-ciga logos
Accreditation for our installation service – BBA certificate number BBA 1249