Is Cavity Wall Insulation Suitable for My Home?

Considering cavity wall insulation but you’re not sure if it’s worth it? No need to worry, we got you covered. Did you know that about a third of all the heat lost in an uninsulated home escapes through the walls, according to the Energy Saving Trust.

Cavity wall insulation fills all the gaps that can be found between external walls in homes, keeping the warmth in, to save both energy and money. But that's not all, insulating your cavities can also help reduce condensation inside the house if this is a problem stemming from your external walls.

Your property will usually be suitable if it meets the criteria:

 The masonry or brickwork of your property is in good condition

 Your cavity is at least 50mm wide

 External walls are unfilled cavity walls

 It is more than 20 years old

energy efficient home

The Big Question: Do I Have Cavity Walls?

It's easier than you think, there are 3 simple steps to check yourself which will tell you if your home has a cavity wall. If in doubt, we can carry out a free professional survey.

Check 1: How old is your home?

Cavity walls didn't really start to be used in general building construction until the early 1930s, which is why the age of your home is a vital first step. If you have an old house without cavity walls then check out what to do here.

When was your house built?

Before 1932 - Unlikely to have a cavity wall

1932 to 1982 - Highly likely

After 1982 - Almost Certain

External wall insulationCheck 2: What pattern are the bricks on your external walls?

There are 3 common types of brick walls.


Measure thickness of external wallsCheck 3: Measure the thickness of your external walls

Cavity walls tend to be thicker than solid walls because they have an air gap between the external and internal wall. It's easy to measure, simply open your front or back door and measure from the outside face of the external wall, through the door to the inside face of the internal wall. Please note: Layers of internal plaster or external render will affect the thickness so a rough figure will do.

Outside Wall Thickness:

Less than 30cm (11.5 inches) - No Cavity Wall

More than 30cm (11.5 inches) - Yes. You got a Cavity Wall


Updated Solution: Icynene Ultra Seal Select Cavity Fill Closed Cell Insulation

At Evergreen Power we use ICYNENE ULTRA SEAL SELECT CAVITY FILL™ as a state-of-the-art cavity wall solution. It is a product that merges the key standard benefits, found in most closed cell spray foam insulations, with innovation in order to improve building performance and minimize environmental impact.

This closed cell foam is suitable for injection into new and existing masonry cavities which may be fully empty or partially filled with rigid board insulation. Icynene Ultra Seal Select Cavity fill completely fills the cavity from the bottom up and as it expands in the direction of least resistance, therefore it will not expand outwards and damage the wall structure.

Icynene Ultra Seal Select has the following unique characteristics

  • Excellent adhesion
  • Low VOC Formulation
  • No odour
  • Low Global Warming potential
  • Environmentally sensitive
  • Airtight insulation
  • Watertight seal
  • Adds structural strength to walls
  • Cavity Wall stabilization
Are you looking fpr latest spray foam insulation?

Alternative Solution: Icynene Classic Pour Fill Insulation

Icynene pour fill spray foam insulation is the best solution on the market to end all cavity wall nightmares. This is a breakthrough in the science of moisture and thermal management. Icynene pour fill is the leading 100% water-blown foam insulation that minimises air leakage for increased energy efficiency, creating a healthier indoor environment, reducing airborne sounds whilst offering greater design freedom.

Icynene's pour fill variation is an insulation and air barrier that is injected into the walls by our expert installers. Our experts will precisely inject the Icynene through a small 8mm hole in the wall. This maximise energy efficiency while still preserving its original architectural details. This makes it ideal for insulating hard to treat buildings such as older buildings with lathe and plaster on existing masonry or stone walls.

Not only this, this insulation method is suitable for dry lining insulation. This goes for new dry lining that have erected studs on the internal face of the external wall. This is as the Icynene fills the wall cavity completely, starting at the bottom and slowly expanding upwards to 60 times its original size to seal all cracks and gaps. Since Icynene expands in the direction of least resistance, it will not expand outward and damage the wall. The pour fill formula has an impressive thermal conductivity of 0.034 – 0.039 W/mK, this will ensure that your home is well insulated.


Cavity Wall Insulation

Benefits of Icynene Pour Fill Insulation

25 Year Manufacturer Warranty

Our product comes with a 25 years manufacturers warranty, and has been BBA, IAB, and ETA Approved. This fit and forget technology needs no maintenance after install, so you won't have to worry about any topping up or upgrades.

Save up to 50% on your Energy Bills

Icynene Pour Fill insulation will air seal your wall and help prevent heat loss; which will make it cheaper to warm your home up in the winter and keep cool during the summer, therefore help you save money every year. By providing U-Value insulation as well as air sealing, it cuts your homes energy loss.

Increased Comfort

Icynene Cavity Wall Insulation creates a cocoon effect, which increases the comfort of your home. Reducing drafts as every crack and cranny is sealed. Also reduces reduces airborne sound from noisy neighbours, street noises and other transferred sounds.

Frequently Asked Questions

What is cavity wall insulation?

Cavity wall insulation fills the gaps between external walls. Every part of the wall must be filled with insulation correctly, so its important the right installer does it for you.

How is the insulation installed?

To insulate your cavity walls, the installer drills small holes at intervals in the outside wall of your home. The installer then blows insulation into the cavity using special equipment. Once all the insulation is installed, the installers fill all the holes in the brickwork.

Can I do the insulation myself?

Filling cavity walls is not a job you can do by yourself, you will need to hire a professional contractor.

What wall type do I have?

Houses in the UK mostly have either solid walls or cavity walls: A cavity wall is made up of two walls with a gap in between, known as the cavity; the outer wall is usually made of brick and the inner layer of brick or concrete block. Whereas a solid wall has no cavity, each wall is a single solid wall, usually made of brick or stone.

Still have a question? Contact our team today