FAQ's

Below are some of the most frequently asked questions we receive, we keep this section updated constantly to ensure you have access to the information you require.

If however, your questions are not answered in this section, please go back to the Contact Us page and send us an email.

Cavity Wall Insulation

Are the cavity wall insulation installers trained?
All installers undergo training by the system supplier to ensure they are competent in CWI and carry a training card. Please feel free to ask to see the training card.

Are there any negative aspects of installing cavity wall insulation?
Modern materials and installation methods mean that there are very few problems with cavity wall insulation these days. It is more important to ensure that the wall at which cavity insulation is to be installed is in good condition and there are no materials internally which may allow water to cross into the internal wall.

Can cavity wall insulation be installed from the external side of the wall?
The installers must undertake checks before and after installation on both sides of the walls, including the checking of any heating appliances. Therefore it is essential that they have access to the property.

Do I need to prepare my home or walls before installation?
Cavity wall insulation is installed by drilling tiny holes in walls and blowing insulation in through them. The process of drilling these holes creates some vibration in the property; it would therefore be wise to remove ornaments and pictures from walls due to be worked on. Keeping pets indoors is also advisable. The installers will need access to the entire property so you should ensure all walls are accessible. If one of your walls are located on a boundary it would be wise to advise your neighbour that the installers may need to work on their property at some point, and it would be wise to obtain their permission.

Does the installation process create a lot of mess?
The drilling process will create a little dust, which will be cleared at the completion of the job. It would be sensible to remove vehicles from the drive and things close to the walls, which will also improve the installer’s access for equipment and tools. It would also be advisable to inform the neighbours and ask them to keep their windows closed and take their washing in during the process.

Does the insulation need to be dense?
As the insulation is contained within a masonry wall, it doesn't have to be 'dense'. For insulation and other purposes, a light density is better. Before installation, the installers will undertake a quality test to ensure the insulation will go into the wall at the right density. The amount of material used will also be noted, to ensure that sufficient insulation has been installed.

How can I insulate my home if it has solid walls?
It is possible to insulate walls which have no cavities, but the process is more complicated. The two most commonly used methods are external cladding or internal lining (dry lining), or using wall battens. External cladding involves applying insulating material to external walls and then adding a protective waterproof finish. Internal insulation can be bought in rolls and applied like wall paper, before being painted over for decorative purposes. Wall battens are used by filling the space between them with insulating material and covering with a plasterboard finish. Steps must also be taken to prevent moisture build up behind the new insulation.

How do you check that the insulation has filled the cavity?
Each cavity wall system has a defined pattern of holes, which has been tested to verify that it results in a complete fill. Most systems have an automatic cut out, which actuates when the adjacent wall area is full. There is tolerance in the injection pattern so that the material will flow past the next injection hole.

How do you tell if my house is suitable for cavity wall insulation?
Before installation, an assessment of your property will be undertaken to confirm that it is suitable for insulation. This assessment can be carried out by a surveyor or the technician before installation.

How long does it take to install cavity wall insulation?
On average, the installation process will take around two hours. This of course, depends on the size of the building to be insulated and how easy it is to access the cavities.

How long will the insulation last?
The BBA has certified this product and agree that it will last the life of the building.

I live in a semi detached house, how do you prevent insulating my neighbours cavity?
The installers will insert a cavity barrier at the party wall line. This is usually a length of bristle brush which goes inside the cavity and will not be visible.

What are the maintenance or servicing requirements of cavity wall insulation?
There is no additional building maintenance required after installing cavity wall insulation, but you should still maintain the rest of your building to a high standard.

What is a CIGA guarantee and how do I get one?
The Cavity Insulation Guarantee Agency (CIGA) provides independent 25 year guarantees for Cavity Wall Insulation fitted by registered installers in the UK and Channel islands. You do not need to do anything to receive this guarantee; we will submit the Guarantee application. The Guarantee is posted to you within days of the application being received at 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.

What material goes into insulating a cavity wall?
The most common forms of cavity wall insulation are mineral wool fibre and polystyrene beads. Mineral wool fibre is a water resistant material made from molten rock spun similar to candy floss, or glass fibre. This is installed by being blown into the cavity. Polystyrene beads are an adhesive version of those found in bean bags and again, can be blown into the cavity.

What will be done if installation is through a painted wall?
Usually, we will paint over the injection holes. However, 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.

Will cavity wall insulation make my home noticeably warmer?
If your heating is not controlled by a thermostat, you should notice a difference after having cavity wall insulation installed. However, if you have a thermostat, it will cut out the heating at the same temperature, so you may not notice the difference in the room with the thermostat. You should however, find that the temperature in other parts of your house improves.

Will the installers fill in the holes drilled?
Yes, the installers will fill all the injection holes with mortar to match the existing wall as closely as possible. He will use a mix that closely matches the existing colour and texture. On pebbledash finishes, pebbles will be applied to the surface to match the existing finish. After weathering, the holes are difficult to see.

Will ventilators in the external wall be safeguarded?
Ventilators supplying combustion air to fuel burning appliances and those which ventilate below timber doors must be safeguarded. The installers will investigate them to check they are already sleeved. If they are not, they will be removed and sealed around them to stop blockages by the insulation. Any redundant vents, such as cavity vents or vents that are used to supply air to open fires in bedrooms may be closed off and filled. The installer should discuss your options with you.

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