Free Cavity Wall Insulation in Wales

Reducing your fuel bills, reducing your Carbon Footprint and helping to keep you warmer.

Telephone:  0800 8 10 10 60:  01443 836 45507960 799 681





Free Cavity Wall Insulation in Cardiff, Swansea, Newport, Merthyr Tydfil and throughout South Wales




Can I get free Cavity Wall Insulation in Wales?

Under the Cavity Wall Insulation Grant scheme, Cavity Wall Insulation is Free in 99% of the cases for those that qualify for the Grant.

The Cavity Wall Insulation Grant qualification was widened in October 2018. Many people who did not qualify for this Grant before then, may now qualify.

Go here, to find out if you qualify for free cavity wall insulation.

There is also a new Cavity Wall Insulation Government Grant scheme available which is based on where you live, but is not based on benefits.

To find out more go here.

We would of course be pleased to give a quote to those that do not qualify for a grant on either scheme.

Click here to complete a short Online Enquiry Form for Home Insulation.


How do you insulate a Cavity Wall?

Most cavity walls can be insulated by injecting insulation material into the cavity from the outside.

We will drill holes (about 22mm) in the outside walls in a set pattern, as specified in the British Board of Agrément (BBA) certificate for the material that is being used. 

The insulation material is the blown through the holes using special equipment (with an adhesive in the case of polystyrene beads which "goes off" after about 20 minutes, thus holding the polystyrene beads together in a loose block). 

The holes are then sealed with cement which has been coloured to best match the colour of the existing mortar.

Filling cavity walls is not a "do it yourself" job and a 3 bed semi-detached house will take between 2 and 3 hours to complete.

Our Installers are among the best in the business, and they will make good the holes with closely matching cement, so that you have a first class result with the minimum of fuss and disruption.

Most of our customers are amazed at how quickly and neatly this operation can be carried out and our work is guaranteed for 25 years by CIGA– the Government backed Cavity Insulation Guarantee Agency – offering you complete peace of mind.


What Free Cavity Wall Insulation do you use to insulate the cavity walls?

We always install “SuperBead” Polystyrene Beads and not “RockWool” (fibre). Polystyrene Bead is a superior material for insulating Cavity Walls, but it is more expensive. “SuperBead” cavity wall insulation has been certified by the British Board of Agrément for the following.

Thermal properties — “SuperBead” cavity wall insulation has a declared thermal conductivity of 0.035.

Water resistance — “SuperBead” cavity wall insulation will resist the transfer of water across the cavity.

Condensation — “SuperBead” cavity wall insulation will contribute to limiting the risk of condensation within the home.

Behaviour in relation to fire —  “SuperBead” cavity wall insulation does not prejudice the fire resistance properties of the wall.

Durability — “SuperBead” cavity wall insulation is durable, rot proof and water resistant. It is sufficiently stable to remain effective as an insulation for the life of the building

“SuperBead” cavity wall insulation is up to 20% more efficient than fibre insulation, such as Rockwool. The insulation is blown into the cavity with an adhesive which “goes off” in about 20 minutes. This leaves a “solid” blanket of polystyrene wrapped around your home, reducing heat loss through the walls by about 70%. There are about 30% fewer holes than using fibre, and the holes are smaller.

The beads have been thoroughly tested and will not deteriorate over time. They are fully fire resistant. They have approval for use in even the most extreme of conditions.


Is my house suitable for Cavity Wall Insulation?

If your home was built after 1925, the chances are that its external walls are made of two skins of brick with a gap or cavity between them, held together with wall ties - this is called a Cavity Wall.

Cavity Wall Insulation fills that gap, keeping the warmth in - thus saving energy. It can also help reduce condensation inside the house if this is a problem on your external walls.

Your home will usually be suitable for cavity wall insulation if:

  • the external walls are unfilled cavity walls
  • your cavity is at least 50mm wide
  • the masonry or brickwork of your property is in reasonably good condition
  • properties built after 1982 now qualify for a grant

But it is not as simple as that.

As a part of the initial survey we also carry out a CASS (Cavity Assessment Surveillance Scheme) survey, which is administered and audited by the British Board of Agrément

The suitability of your walls to be insulated will be assessed by way of an extensive survey of the walls and property.

This survey includes, but not limited to:

A small test hole will be drilled into the wall of each elevation. A borescope will be inserted into each hole and the cavity will be examined - photographs of the cavity will be taken, along with measurements of the depth of the cavity.

All walls are carefully examined and any remedial work noted (which has to be completed before the walls can be insulated), such as cracks, unfilled holes, etc.

Gutters and downpipes are examined for any leaks or blocks and proper drainage.

The survey will take about 2 hours.

The report and photographs are then uploaded to the British Board of Agrément platform for auditing.

This is a part of the greatly improved quality control measures found within the new free Cavity Wall Insulation Grant scheme.


Is the Free Cavity Wall Insulation guaranteed?

Yes, it comes with a 25 year guarantee issued by the Cavity Insulation Guarantee Agency (CIGA).

The Cavity Insulation Guarantee Agency provides independent 25 year guarantees for Cavity Wall Insulation fitted by registered installers in the UK and Channel Islands.

However, they will only issue a guarantee if the property has passed a CASS survey.

A grant will not be allowed unless a CIGA guarantee is issued.

The Government regards cavity wall insulation as "the most effective energy savings measure that most people can carry out on their homes" and a major contributor to reducing carbon emissions.

CIGA was established in consultation with the Government's Energy, Environment and Waste Directorate (a division of DETR) to provide householders with an independent, uniform and dependable guarantee covering defects in materials and workmanship.

Independent research carried out for the Department of the Environment, Transport and the Regions (DETR) has confirmed that cavity wall insulation is a very reliable process.

Problems are therefore extremely rare, but if they do occur, CIGA has the expertise to ensure that they are swiftly rectified. The new CASS survey will also reduce the potential for future problems, by only insulating walls that are suitable.

CIGA also operates and administers the Cavity Wall Insulation Self Certification scheme (CWISC) in association with the British Board of Agrément. The scheme provides homeowners with the comfort of knowing that work by registered contractors complies with the requirements of the Building regulations.


Will Cavity Wall Insulation help to reduce my fuel bills?

 Yes, it will, and it will also reduce your Carbon Footprint, and can help reduce/eradicate Condensation.

These are the percentages of heat loss though the different parts of a house:

  • Walls = 35%.
  • Roof = 25%.
  • Floor = 15%.
  • Draughts = 15%
  • Windows = 10%

Uninsulated walls lose 35% of the total heat loss of a house. Cavity Wall Insulation will reduce that heat loss by 70%.

This means that the total heat loss from the walls of your home would reduce to just 10% - a reduction of 25%.

This in turn will reduce your heating bills by about 25% - that is about £150 per year for the average house in the UK.


Should I have Free Cavity Wall Insulation installed if I have damp in my home?

 No, No, No!

If you have any damp patches on the inside of your external walls then they should not be insulated until the cause of the damp has been resolved.

In fact, if there is damp, the property will fail the CASS survey, and we will not install cavity wall insulation.

To get a Grant there must be a 25 year guarantee issued. To get a 25 year guarantee issued the property must pass a CASS survey.

So if there is damp there is no Grant - it's as simple as that.

If however, it is "Black Mould / Spots" then this is probably Condensation and not Damp. 90% of the time Condensation is a lifestyle issue rather than a structural issue. However, Cavity Wall Insulation can help reduce/eradicate Condensation.


How are the Cavity Wall insulation Grants funded?

The Government have European targets to reduce Carbon Emissions.

The Government, as Governments do, passed the buck. They gave a Legal Obligation to the Gas and Electricity companies to reduce Carbon Emissions. This is know as the Energy Company's Obligation, ECO for short.

The Government (OFGEM) have "deemed" an amount of Carbon Emissions saved for each type of property insulated - terraced, semi-detached, detached, 2 bed, 3 bed, 4 bed etc. These Carbon Emission savings are then "sold" to one of the Gas and Electricity companies so that they can achieve their  Energy Company's Obligation - and that is how it is funded. We all pay an amount on our fuel bills towards this Grant fund, so yes, we pay for it, as usual.


Can Free Cavity Wall Insulation cause Damp?

 According to the Cavity Insulation Guarantee Agency, damp problems arise in 3 houses out of every 1,000 insulated.

The problems of damp and cavity wall insulation (CWI) are virtually all historical, and were caused by inappropriate insulation being put into inappropriate walls.

Rockwool used to be the main insulation used for Cavity Wall Insulation, this has now been replaced by polystyrene beads which is a much better material for CWI. Even so, when polystyrene beads were first used they used the little white soft polystyrene beads, just like the ones found in "bean bags". In some cases these also caused issues - mainly due to their size, structure and not being very good at repelling water.

Today larger grey polystyrene beads, shaped like a coffee bean are used - which are also impregnated with a water repellent.

But the main problem was caused by salespeople knocking doors telling people they could have CWI for free, and then not carrying out a full pre-installation survey. As a result of this, houses that should never have been insulated were insulated.

In April 2017 the British Board of Agrément (BBA), was put in charge of ensuring that "inappropriate" houses should not be insulated, and this gave birth to the Cavity Assessment Surveillance Scheme (CASS). The BBA are the body responsible for certifying that building materials are "fit for purpose", and lay down how those building materials should be used within the certificate that they issue for that material.

CASS involves a full survey of the property to be insulated taking about  2 hours. The survey of your property includes, but is not limited to, camera shots of the inside of the cavity and other factors which may make a property inappropriate to insulate - these would include factors like the age of property, condition of walls, depth of cavity, construction type, condition of gutters and downpipes,etc.

Leaky gutters and downpipes is one of the main causes of damp in homes.

The photographs and other data are then uploaded onto the BBA platform for auditing. Every survey is audited by the BBA at desktop level, and 1 in 10 are audited with a visit to the property by a BBA surveyor to audit the survey that has been carried out.

This level of "quality control" should resolve the historical problem of insulating inappropriate properties, and therefore the potential for damp caused by CWI.

Up to 2017 CIGA (the Cavity Insulation Guarantee Agency who issue the 25 year guarantee) states that there could be problems in 3 out of every 1,000 properties who have had CWI.

The actions taken in April 2017 by the British Board of Agrément and the CASS survey, should greatly reduce this figure further.





For further details call us on one of the numbers below, or email us on

 or complete the online enquiry form below.

Landline:     01443 836 455

Freephone: 0800 8 10 10 60

  Mobile: 07960 799 681 (Tap and call from Smartphones)

Click here to complete a short Online Enquiry Form for Home Insulation.

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