Cavity wall insulation
Cavity Wall Insulation

Cavity Wall Insulation

Around 33%* of a home’s heat is lost through uninsulated cavity walls. By having insulation professionally installed into the space between your home’s two layers of brick, you will save energy and reduce your heating bills.

You can expect to save around £300* per year on your energy bill (based on a gas-heated semi-detached home) rising to £520* per year (based on a gas-heated detached home).

Save energy with cavity wall insulation

Our team can insulate the walls of an average 3 bed-semi in just a few hours. The team will inject EPS beads into the cavity from the outside of your home via small, carefully drilled holes which are made good with cement afterwards. Afterwards, less heat can escape from your home through the walls.

WATCH: our handy video guide

Our handy video guide to cavity wall insulation

Costs & funding

As an accredited installer, we have access to various pots of funding that can make insulation FREE or very low-cost for you. The funding comes from places such as energy companies, local authorities and government. We’ll check what you’re entitled to when you contact us.

For example, currently the Great British Insulation Scheme (GBIS) enables millions of UK homes to be installed with cavity wall or loft insulation for FREE, by one of our professional teams. Don’t delay…

People with homes built from cavity walls (as opposed to solid walls) are recommended to consider cavity wall insulation to bring the property’s energy efficiency up to today’s standards.

Homes built with cavity walls were very often constructed with no insulation or with insulation that is now considered inadequate.

Who needs cavity wall insulation?

Home visits to suit you

We’ll ask a few questions over the phone and then book you a FREE home visit at a time to suit you.

Getting cavity wall insulation

Get in touch with us, even if you’re unsure of your wall type, and we’ll advise over the phone or by email. Then we’ll book you a FREE home visit for a Home Surveyor to come and take a look at your property and confirm suitability, do a few checks and take some measurements.

The insulation will be fitted shortly after by one of our friendly technician crews.

hot offer fully funded insulation

We aim to get back to you by the next working day

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Identifying your wall type

As well us using the age of your property to determine its wall type, you can also take a look at the brick pattern.

Example of solid wall

Solid wall

The bricks will have an alternating pattern so that some bricks are laid lengthways and some bricks are laid widthways, showing the smaller ends.

Example of cavity wall

Cavity wall

The bricks will have an even pattern with all the bricks laid lengthways.

Best quality,

EvoBead is our sister company that manufactures and supplies high-performance EPS bead for cavity wall insulation from their premises in South Wales.

All our cavity wall installations are carried out using the EvoBead product meaning we are absolutely guaranteed of its thermal properties and performance.

evolve hes logo
  • Award-winning
  • KIWA approved 
  • 10-year product guarantee
  • No water absorption 
  • Thermal rating of 0.033 W/mK
  • 50% fewer drilling/injection holes 
  • 33% reduction in ladder movements

evolve installation team

Why choose Evolve?

We’re great at what we do and our team has over 450 years’ experience between us so we know how to do an excellent job. We only use the best materials and all our surveyors and engineers are highly trained and take pride in their work.


Established in 2015


60 members of staff


450 years of combined experience


Over 15,000 homes decarbonised since 2015


A further 80 homes decarbonised every week


3,000 cavity extractions project managed

call us today evolve home energy solutions

We’re open between 9am and 5pm, Monday to Friday. Or drop us a message and we’ll get back to you ASAP.

Cavity Wall Insulation FAQs

What is a cavity wall?

A cavity wall is a construction type whereby a wall is constructed of two layers of a brick with an air gap (or cavity) between them. It is how homes have typically been constructed in the UK since the 1930s.

What is cavity wall insulation?

Cavity wall insulation is when insulation is injected into the air gap (or ‘cavity’) between the two layers of bricks that make up a cavity wall. The insulation creates a thermal barrier, preventing excessive heat loss through a home’s walls.

Why should I have cavity wall insulation?

Homes should be cavity wall insulated, if possible, to help the occupants reduce their energy usage and therefore lower their energy bills.

How long does cavity wall insulation take to install?

A typical three-bed semi can be installed in around half a day.

What prep do I need to do before cavity wall insulation is installed?

The installation crew need good access to your home’s exterior walls so please move flower pots, hanging baskets and other obstructions.

How much money can cavity wall insulation save me on my heating bills?

Cavity wall insulation can save up to £520 per year* on a gas-heated, detached home’s energy bills.

What insulation product do you use?

We install EvoBead, manufactured by our sister company so we are 100% sure of its exceptional insulating properties and performance.

How much does cavity wall insulation cost?

It depends on a range of factors so it is hard to give a figure. Plus, we often have access to funding that can make cavity wall insulation free or partially funded, depending on your circumstances. Our Home Energy Surveyor will advise on this during their home visit.

Can I get cavity wall insulation for free?

Yes, sometimes we can install cavity wall insulation completely free of charge, depending on the funding that is available at the time, your circumstances and your property type.

* Estimates taken from the Energy Saving Trust, August 2023 (