By installing cavity wall insulation, you’ll stop up to a third of the heat from your home escaping. So, not only will you have a cosier home, but you’ll spend less on heating it too.

If your home was built after 1930 it is likely that you have cavity walls. This means the outside walls are made up of two layers with a gap or cavity in between. Insulating cavity walls is an excellent way of reducing costs and conserving heat.

You should be able to tell which wall type you have by looking at the brickwork on the outside of your house. The picture below shows how the brick work looks on a typical cavity wall construction.


If the brickwork isn’t visible, you may also be able to tell which wall type you have by measuring the thickness of wall by a door or window. If the wall is wider than 260mm it is likely to be a cavity wall – anything less is likely to be a solid wall.

Usually your home will be suitable for this type of insulation if the cavity is at least 50mm wide, the brickwork is in good condition, not exposed to driving rain, and walls are accessible from the outside. Houses less than 10 years old will generally already be insulated.

Please note that if you have any damp patches on your internal walls then they should not be insulated until the problem is resolved.

The actual process involves drilling small holes in the external walls and ‘blowing’ the insulation into the cavity. The holes are then filled in so that they are barely noticeable. The process usually takes about two hours for an average size house with good access.

See some of the frequently asked questions below for more information or contact our team on 0117 352 1180.

How much could I save on my heating bills?

Every household is different and the possible savings are dependent on the size and type of your property as well as any existing insulation measures and your average energy consumption.

Property type  Detached  Semi-detached or end terrace   Mid-terrace  Bungalow  Flat
 Annual saving  £250  £145  £95  £100  £75

Source: Energy Saving Trust

Can my house have cavity wall insulation?

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

  • external walls have unfilled cavities
  • the cavities are at least 50mm wide
  • the brickwork of your property is in good condition
  • the property is more than ten years old (most new builds will have insulation already)
  • the walls are not exposed to driving rain.

How is cavity wall insulation installed?

Small holes about 22mm wide, at 1 metre intervals are drilled into the external walls of your house, through to the cavity space. Specialised equipment is then used to “blow” the insulation through these holes and into the cavity. Once the whole wall has been filled, the installer will fill any holes that were made so that they are barely noticeable.

How long will it take?

The whole process usually takes about two hours for an average sized house with good access to the walls being treated.

Will I have to pay anything up front?

If you need help to cover the installation costs, there are a number of potential options available to you. We’ll look at your eligibility and can chat through the finance options to help you spread the costs.

What happens when I decide to go ahead?

Our installation team will contact you to schedule your work.

Can you be flexible with the dates for my installation?

Yes. But do remember you may need work to be completed by a certain date to qualify for funding. Our installation team will be able to advise you if this is the case.

Do I need to be at home when the work is carried out?

Yes, initially to give our installers access.

What if my external walls aren’t easily accessible?

When cavity wall insulation is installed, it must be “blown” from the outside of the house into all parts of the wall. The installer must be able to access all parts of the external walls to do this properly. The installer may also need to insert a “cavity barrier” which prevents the installation affecting your neighbours if your external walls are attached to another property.

What about damp?

If you have any damp patches on any of your internal walls then they should not be insulated until the problem is resolved. It is best to speak to a builder who specialises in damp prevention who should be able to advise you on any repairs that may be needed.
Our installers will always ensure that there are no problems with damp before commencing work.

Other questions…

The information above covers the most common questions but if you have any questions at all about the measures on offer, please call our team on 0117 352 1180.