Bonded Bead Cavity Wall Insulation

What is Bonded Bead Cavity Wall Insulation?

Cavity wall insulation is suitable for houses built after the 1940s which have cavity walls. Not only will it help the walls retain heat, allowing your home to maintain an even temperature, but it also helps to reduce condensation and assist in eliminating rodent infestation.

Our Insulation

We use KOREFILL cavity wall insulation beads, which consists of an expanded polystyrene material in bead form which is injected into the wall along with a bonding agent. The bonding agent is used to provide long-term stability to the insulant.  This insulation is NSAI agrement certified and is installed in line with both NSAI and manufacturer guidelines.

How it Works

Bead insulation fills 100% of the wall cavity, ensuring there are no cold spots.  It is extremely good at insulating and you should be able to recoup your costs in energy bills within 2-3 years.  It is a cheaper and more durable form of insulation than spray foam.

Our Guarantee

Modern cavity wall insulation has exceptional durability and does not settle over time.  This type of insulation will last the entire lifetime of your building and does not require any maintenance. In fact, we give a 24 year guarantee on our cavity wall insulation work.

Environmental Impact

Cavity insulation is 100% recyclable, is not harmful for the ozone, has a low global warming potential, and poses no threat to the environment.

Problems with Damp

If you are suffering from dampness in the house we will conduct a survey to identify the cause of the problem. If the damp is being caused by condensation, bonded bead insulation will help. It won’t completely cure the problem, but it will make a significant difference. Dirty wall ties or something bridging the cavity can also cause areas of spot damp. These problems will be rectified before installation work is carried out.

Cavity wall insulation beads will not allow dampness or moisture to penetrate the cavity in a properly constructed wall. This is due to the capillary action of the bead allowing gravity to draw any moisture present down the inner surface of the outer leaf to drain away at foundation level. The honeycombed nature of the bead once bonded will not allow dampness to travel across the cavity.

Cavity wall insulation cannot cure rising damp, which is due to a faulty damp course. If this is present, we can arrange for specialists to fix the problem before we install your insulation.


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Before Installation

Before the installation commences, ensure all the windows are firmly closed and external doors sealed tightly. If you have valuables on the walls or window-sills it would be wise to remove them as the drilling causes vibration. If children or pets are likely to be upset by the noise of drills, it may be a good idea to move them for a few hours while the work is going on.

Cavity wall insulation installation is generally not affected by weather conditions, we can install your insulation in all but exceptional weather circumstances.

The Installation Process

  1. Cavity is measured and assessed by our surveyor.
  2. Any existing problems with damp are assessed and rectified.
  3. All under floor vents currently in use will be assessed, and if they do not have a sleeve in place, we will remove them, sleeve them and replace the vent covers where necessary.
  4. A vertical cavity barrier will be inserted at the boundary line of your property to prevent any material from encroaching into your neighbours property.
  5. The insulation technicians follow a strict drilling pattern set out by the Irish Agrement Board (IAB) to ensure all areas of the cavity are filled.
  6. KOREFILL Beading is injected into the cavity by compressed air and as the bead enters the cavity it is coated with a bonding adhesive.
  7. All penetration holes are filled with the correct mortar to suit the wall.
  8. Chimney flues will be tested after completion of the work in order to confirm they are clear.

Minimal Disruption

All work is completed outside your property, with the exception of smoke tests and loft inspections if required. There is little or no disruption inside the house. There is a certain amount of dust outside from the drilling which is unavoidable and a few of the beads may blow away while the job is being installed. After completion, we clean up the dust and the area around the house will be washed down and left as clean as possible.


The adhesive is a water based solvent and does not give off any toxic fumes. The only smell present is the smell of the glue itself, which clears away after a few hours. In no way will either the adhesive or the polystyrene bead cause health problems. Both materials have been thoroughly tested and offer no threat to adults, children or pets.

After Installation

You can use all household equipment immediately. You can use your central heating or light a fire straight away.

Bonded bead insulation and its installation have no effect on the integrity of the building. There is no additional risk of fire as there is insufficient air in the cavity to sustain a fire provided the cavity is capped as per regulations.

Future Work on Your Home

If you are planning future work to your property, you do not need to worry about the beading leaking out as the adhesive will hold it in place. It is possible that a small amount of the bead around the disturbed area may come free, but this can be prevented by blocking the cavity at the areas being opened with fibreglass.


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Technical Information

KOREFILL can be used in new or existing dwellings, apartment blocks, hotels and office blocks.
This product can be used for new or existing cavity walls up to 12 meters in height, subject to the conditions contained in Part 3 of the attached Certificate. It also facilitates the control of surface and interstitial condensation in walls. It is approved for installing in masonry cavity walls for both full fill or partial fill situations when a residual cavity width of 40mm or greater exists subject to the conditions identified in Cl. 2.4.4 of the attached certificate.

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Bonded Bead Cavity Wall Insulation FAQs

Q: Is my home suitable for cavity wall insulation?

If your house meets the following criteria, you will be able to get cavity wall insulation:

  • You have brick cavity walls with a minimum of 510mm cavity.
  • The brickwork is in good condition.
  • Your walls are less than 12m high and all external walls are accessible.

Q: How do I know if I have cavity walls?

Cavity walls are essentially two separate thin walls with a gap between them. The two walls are called ‘leaves’ and are connected by metal wall ties. You can tell if you have cavity walls in a few ways.

  • If your house was built any time after 1920, you may have cavity walls. This is not a hard and fast rule as some houses were built with solid walls after the 1920s.
  • Measure the thickness of your walls at an outside door or window. If your walls are more than 260mm thick, they are most likely cavity walls.
  • Check the brickwork - if all the bricks are laid lengthways, you most likely have cavity walls. If the bricks are laid in alternating directions, you have solid walls.

Q: How do I know if my cavity walls are already insulated?

Houses built after 1990 often already have cavity wall insulation. If you are buying a house, you can check with the seller if it already has insulation. Alternatively, you can check for marks on the outside walls of your home. Inserting cavity wall insulation requires 1 inch holes to be drilled in the walls at regular intervals, and whilst these will have been filled, you may still be able to make them out.

If your home already has cavity wall insulation but you’re still not warm enough, it may suggest that your cavity wall insulation is old or faulty. This can be rectified by removing the old insulation and replacing it with newer, better quality insulation. We can not only install your new insulation but take out the old insulation and dispose of it in the correct manner.

Q: What if I don’t have brick walls?

If your house has been rendered, it may be hard to tell if they are made out of brick or another material, but you can check the thickness of your walls as described above and this will give you a clue as to whether you have cavity walls made of brick.

If your walls are clearly made of stone or your building is timber, steel framed or concrete, you won’t be able to use cavity wall insulation. But it doesn’t mean you can’t insulate your home! Check out our general insulation page ( for other types of insulation.

You can tell if you have a timber framed house by checking in your attic. If your party or gable walls are made from timber, then you have a timber framed house.

Q: Are there any other reasons I may not be able to get cavity wall insulation?

If the cavity between your walls is too narrow, which is rare, but possible, then it would not be possible to install cavity insulation.

Certain geographical locations with adverse weather conditions may not be suited to cavity wall insulation, however, this does not apply to Dublin and surrounding areas where we carry out most of our work.

If we cannot access the outside walls of your property, we will not be able to install cavity insulation.

However, even though the above factors prevent the installation of cavity insulation, there are other types of insulation, which means that there are other options for insulating your property.

Poor brickwork will not prevent you from getting cavity insulation, although the brickwork must be repaired before we can commence installation. Similarly with dampness and wet patches on your internal walls - whilst the insulation cannot be installed when interior walls are wet, this can be rectified in order to subsequently install cavity insulation.

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