Heatpac Employee holding injector
Heatpac employee holding pipe while insulation is pumped inside the cavity.

What is cavity wall insulation?

Most homes built since the 1920’s have cavity walls, i.e. an inner and an outer ‘skin’ with a gap between them. Filling this gap with insulation material improved the retention of heat on the inside of the property.

What are the benefits of cavity wall insulation?

Not only is effective cavity wall insulation good for your home, it is good for your pocket and good for the environment.

Installing cavity wall insulation is one of the most effective energy saving steps you can take,
up to 35% of heat loss in a home can be through the external walls. By installing insulation not only will you save on your heating costs for many years to come, your carbon footprint will also be significantly reduced as a result, producing far less Carbon Dioxide.

Is my property suitable for cavity wall insulation?

If your property was built after the 1920’s, you almost certainly have cavity walls. Older houses are more likely to have solid walls.

Your home will usually be suitable for cavity wall insulation if it meets these criteria:

  • Your cavity is at least 50mm wide.
  • The masonry or brickwork of your property is in good condition.
  • It is more than 10 years old (most newer houses will have insulation already).
  • The walls are not exposed to driving rain.

Contact us today to schedule a free survey in which we will check the condition of your current masonry or brickwork, and any existing insulation if it exists.

Cavity Wall Insulation Extraction

Improving your home by installing new cavity wall insulation almost always requires complete removal of current cavity wall insulation material.

Heatpac offers specialist removal of defective or old cavity insulation.

There are different materials which may be in the wall, it can be in very different condition and the building itself may have access issues. For example, loosely installed dry fibre will extract very easily but flood damaged or very wet fibre will take much longer.
Expanded foam can vary every time due to the adhesive mix when installed and so one foam job can take twice as long as an identical property down the road.

High rise properties would have to be on a site by site basis. Anything over 4 storeys will require scaffolding and potentially mast climbers depending on the property construction. You would not be able to extract cavity wall insulation by abseiling.
To find out for certain how much it will cost to remove your cavity wall insulation, please contact us.

How is cavity wall insulation installed?

You’ll need a registered installer (that’s us) to fit cavity wall insulation – it’s not a job you can do yourself.

Firstly we conduct a survey which establishes if and which cavity wall insulation is suitable for your home. (Our free surveys come with no obligation)
A series of small holes are drilled into the mortar joints on the external brickwork. Glass wool is then blown into the holes until an effective heat seal is formed within the cavity.
Once the installation is complete we make good all brickwork, blending in the installation work to retain the look of your property.

The majority of work is carried out on the outside of your home with minimal inconvenience to you.
We can insulate homes with different cavity specifications such as hard to treat/narrow cavity and partial fill.


Q: I’m not sure what, if any, insulation is installed into the cavity, can you help?
For all interested we offer a free, no-obligation, survey of all properties with an appropriate cavity or loft space.
Use our Contact Form to get the ball rolling on a time and date that suits you.

Q: What if there is already insulation material in the cavity?
We do not recommend and will not mix insulation material into the same cavity, to install new cavity wall material the old material will need to be removed.
For an extra fee we offer a removal service and will take care of the disposal.

Q: How long will it take?
Between two to three hours for a three bed room semi-detached house, longer if removal of old material is necessary.

Q: How much does cavity wall insulation cost?
The cost of cavity wall insulation is affected by many factors, instead of vague estimates, we offer free, no-obligation, surveys to accurately determine the cost of installing insulation into the cavity.

Q: Will installing cavity wall insulation help me save money?
Yes, The Energy Saving Trust (EST) states that having your cavity walls insulated as opposed to uninsulated, can save you more than £280 per year on your heating costs.

Q: Will it make a mess?
Cavity wall insulation, both wool and bead, is injected from the outside so the installers will not be working inside the building.
Installing cavity wall insulation does include activates that create can create debris, like drilling, which we will clean up.

Q: What do you use as insulation?
We use either Knauf Earthwool or Thermabead/Polybead depending on customer preference or surveyor advice.

Q: Do/Can you use foam?
We can extract previously installed foam but we do not install it ourselves and currently have no plans to start doing so.

Q: Will the work be guaranteed?
Yes. The work will be guaranteed for 25 years by The Cavity Insulation Guarantee Agency (CIGA).
The guarantee covers defects in materials or workmanship, in connection with the installation, which will be rectified without charge.
The guarantee remains valid for all subsequent owners of the property.

Q: Are there any grants available to cover the cost of insulating my home?
Various grants and schemes are available to help with the cost.
You can find more information about available grants via:
ECO4 (Means-tested benefits required)
GBIS (D-G EPC and Council Tax band of A-D)

Q: Where can I find more information about home insulation?
Contact us for free advice on what you can do to improve your home’s insulation.
Online Contact Form:https://heatpac.co.uk/contact/
0800 552525 (09:00 – 16:00) (Mon-Fri)
01642 222248 (09:00 – 16:00) (Mon-Fri)