How Does Cavity Wall Insulation Work?

At Eco-Green Deals we have specially trained surveyors to identify your property and its requirements. Our engineers carry out an initial survey thus enabling us to discuss your property needs.

Given our experience and expertise of cavity insulation we can guide you from an initial survey right though till the installation of your cavity.

Our cavity wall insulation projects come with a 25 year guarantee which is administrated by CIGA thus providing you the peace of mind you most deserve.


Cavity wall insulation fills that gap, keeping the warmth in to save energy.


If your home hasn’t been insulated or you are not sure please contact us and we will gladly assist you further, you will qualify for FREE Cavity Wall Insulation under the governments ECO Scheme.

Installation process

To insulate your cavity walls, our fully trained technicians drills small holes around 22mm in size at intervals of around 1m in the outside wall of your home. With specially designed equipment, we then blow insulation into the cavity. Once all the insulation is in, we then fill the holes in the brickwork so you’ll barely notice them.

text2Text ECO to 60777

Where we will contact you to begin your application for FREE Cavity Wall Insulation

Cavity Wall Facts


Annual saving

Installation cost

Payback time

Carbon dioxide saving per year

Cavity wall insulationUp to £140£450 to £500Under 4 yearsAround 560kg

These are estimated figures based on insulating a gas-heated, semi-detached home with three bedrooms. The average installed cost is unsubsidised.

*SOURCE: Energy Saving Trust 2013

Frequently Asked Questions – Cavity Wall Insulation

What is a cavity wall?

The external wall of a house is constructed of two masonry (brick or block) walls, with a cavity (gap) of at least 50mm between. Metal ties join the two walls together.

How long does it take to install?

Cavity Wall Insulation normally takes around two/three hours to install, but the time does depend on the size of the house and other factors, such as access.

Is my house suitable?

If you contact us we will carry out all the preliminary checks before an install can take place. We will undertake an assessment of your property to confirm that it is suitable for insulation.

Do I have to do anything before the installation?

The drilling process does create some vibration – so it would be wise to remove ornaments, particularly on external walls, for their safety and your peace of mind.

The Technician will need access to all walls, so he will need to get inside attached garages, lean-to sheds, conservatories etc. The insulation can only be really effective if all walls are done. If you have a wall right on the boundary, you may like to mention to your neighbour, that the Technician will need to go onto their property.

Is there much mess?

The drilling process inevitably creates a little dust, which will be cleared at the completion of the job. It may be wise to remove vehicles from the drive and things close to the walls. This will also give the Technician better access for equipment and tools.

My house is semi-detached, how do they stop insulation going into my neighbour’s cavity?

Assuming your neighbour’s house is not already insulated, the Technician will insert a cavity barrier at the party wall line. This is usually a length of bristle brush. Of course, if the neighbour’s house were to be insulated at the same time, the cavity barrier would not be needed.

Are the Technicians trained?

All Technicians undergo training by the system supplier and the installing firm to ensure they are competent in CWI and carry a training card. Please feel free to ask to see the training card.

What about filling the holes?

The Technician will fill all the injection holes with mortar to match the existing brickwork as closely as possible. We will use a mix that closely matches the existing colour and texture. On pebbledash finishes, we will apply pebbles to the surface to match the existing finish. After weathering, the holes are difficult to see.

But my house has painted areas?

Normally, the installing firm will not paint the injection holes. Unfortunately, even if the original paint is used, it may not match due to weathering. So it may be necessary for you to consider painting the area, after the mortar has dried.

Do I apply for the CIGA 25 Year Guarantee?

No, we will submit the Guarantee application. The Guarantee is posted to you within days of the application being received at CIGA_0001_ciga. – Keep it safe

CIGA is non-profit distributing; its only function, is to stand as guarantor for the promises set out in the Guarantee. It has the resources to meet the promises made in the Guarantee.

All professional approved installing firms are members of CIGA and can apply for a CIGA Guarantee, for properties built with traditional cavity walls. You should insist on a CIGA Guarantee, since nothing else can give you the level of assurance to which you are entitled.

Will my house be warmer?


With CWI, you should find that the house holds its temperature for longer, therefore the time between heating cycles may be longer. The result should be a more even temperature throughout the house as well as a reduced fuel bill.

Is there any maintenance or servicing requirements?

No, not to the Cavity Wall Insulation, but normal building maintenance is needed.

If I am concerned after the installation – what should I do?

Talk to us and tell us the nature of your concern. A contract exists between you and us, so you must give us the opportunity to investigate your worries.

We will help.

Are there any grants available to help assist with the payment of Cavity Wall Insulation?


A set criteria has to be met under the Governments Energy Company Obligation (ECO) scheme the majority of our customers qualify. All you have to do is get in touch and we will take care of the rest.

The Technical Bit...?

Typical Cavity Construction (Suitable)Typical Solid Construction (Non-Suitable)

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Eco-Green Deals are currently filling cavities around the entire UK under the governments ECO obligation scheme. We would love to hear from you