Can you improve cavity wall insulation?

Author: Werner Von  |  Last update: Saturday, September 27, 2025

Retrofitting cavity walls can improve your energy savings by 10% on average. Polystyrene beads and polyurethane are the best retrofit insulation materials available.

Can you upgrade cavity wall insulation?

As long as the insulation within your cavity wall isn't damaged, then it can be topped up. This can be a difficult process, and unless there has been severe damage it is unlikely to offer enough of a benefit to your levels of heat loss to justify the price.

Why is my house so cold even with cavity wall insulation?

This is another symptom of your cavity wall insulation's deteriorating health. Your boiler and radiators are working overtime to try and warm your house up, the heat wants to escape, and your insulation is allowing it! If your insulation can't even hold itself up, then there's no chance of it holding your heat in.

Is it possible to top up cavity wall insulation?

Topping up your cavity wall insulation can be beneficial, especially if the existing insulation has settled or degraded over time. Often this can happen with certain materials like expanded foam or polystyrene beads.

Can you have cavity wall insulation redone?

When the cavity is emptied, it should be refilled with a suitable option, such as injecting special insulation material like polyurethane foam, or some other alternative. Cavity wall extraction teams will cover up the holes, usually in the outer wall, with cement, so you would barely know that they have been there.

Cavity Wall Insulation Problems ~ The Ugly Truth

How can I improve my cavity wall insulation?

Many cavity walls can be insulated by injecting insulation material into the cavity from the outside. A specialist company will drill holes in the outside walls, inject insulation through the holes and then seal them with cement.

Why are people removing cavity wall insulation?

One of the main reasons as to why people decide to have their cavity wall insulation removed is because their property isn't suitable for it. For instance, if your property is often subject to wind-driven rain, then it is not recommended that a cavity wall is in place.

Can you have cavity wall insulation done twice?

I'm sure you're aware that you can't fill, or 'top up' a cavity that's already been insulated, it can void your insulation guarantee provided by CIGA!

What is the life expectancy of cavity wall insulation?

Cavity wall insulation typically lasts between 20 and 100 years, and many insulation manufacturers offer a 25-year warranty on their materials. If your home was built after the 1920s when building regulations changed, then it likely has cavity walls instead of solid walls.

Can I put insulation on top of insulation?

In many cases you can add new insulation on top of old insulation, unless the old insulation is wet, mouldy, or vermiculite. If the old insulation is dry but appears to have previously been wet, you should look for the cause and repair the problem.

What is bad about cavity wall insulation?

The top five problems with cavity wall insulation
  • It's not suitable for all homes.
  • It won't be effective if it's installed incorrectly.
  • It won't work if the property has any cracks.
  • It can sometimes damage the property.
  • It can lead to inadequate ventilation.

How can I get my cavity wall insulation check?

Borescope Inspection

A qualified professional can use a borescope to inspect the cavity walls of your property. This will help determine whether insulation has been installed and whether the insulation remains in a good condition.

Why does my house feel cold at 20 degrees?

There may be drafts and pockets of colder air near the floor; The walls are colder and don't emit the usual amount of infrared radiation, so you lose heat due to your body emitting more IR than it receives; You may spend more time indoors and hence have less physical activity, so your body generates less heat.

What houses should not have cavity wall insulation?

Properties without a DPC, or where the DPC is too low (typically less than 125mm from the ground) and a French drain has not been installed. Some properties with raked mortar joints. Properties with a cavity wall under 50mm or over 150mm. Properties that have significant rubble or mortar ingress in the cavity.

Is it worth retrofitting wall insulation?

Should I get cavity wall insulation for my retrofit? Retrofitting insulation into a cavity wall can be worth it as it can decrease energy consumption by 10%, resulting in between £110 to £405 decrease in bills depending on the size of your home.

How do you increase insulation in an existing wall?

Insulating Finished Walls

Drill-and-fill method: Small holes are drilled into the wall cavities, and loose-fill insulation is blown in. This method works well with cellulose or blown-in fiberglass insulation. Injection foam: Similar to the drill-and-fill method, but using expanding foam insulation instead.

Can I upgrade my cavity wall insulation?

Talk to the experts. Old outdated cavity wall insulation could be resulting in your home losing more heat than it needs to. We can assess the current state of your cavity walls and offer advice on the best course of action in upgrading your cavity wall insulation.

Should I replace 50 year old insulation?

Unfortunately, the majority of homes built 50 years ago were not insulated at all. It is important to be aware of these insulation issues if your home is 50+ years old. Replacement (or new installation) may be necessary if your home is drafty, if you have high utility bills, etc.

How do you know if cavity wall insulation has failed?

How do you know if your cavity wall insulation has failed? Cold and wet patches on internal walls could be signs of failed CWI. Water-damaged and blistered plaster, wallpaper or painted surfaces are also warning signs. On the external wall, look out for spalled or cracked brickwork.

Does doubling up insulation work?

Doubling the thickness of insulation will double the insulation's R-value, cutting heat loss in half. Each time the insulation layer is doubled in thickness, this rule applies.

Should I remove old cavity wall insulation?

There are a few reasons why you may need to remove cavity wall insulation. For example, you could be having internal damp issues, or problems with vermin. The insulation may have been installed incorrectly, or is experiencing degradation. In this guide, we'll look at the average cavity wall insulation removal cost.

Does cavity wall insulation make a house hotter in summer?

Does Insulation Make Your House Hotter In Summer? Insulation only slows down the transfer of heat from the outside to the inside, or vice versa, and doesn't directly heat things up or cool things down.

What is the downside to cavity wall insulation?

The beads can pull away from the crevices of your cavity, or the bonding agent can wear down, this can also cause dampness in your home as the moisture entering your cavity will cling to, and penetrate the internal walls of your home.

How do I know if my cavity wall insulation needs replacing?

Signs When You Need Cavity Wall Insulation

Cold spots: If you feel uneven warmth or cold spots on the wall, it can be a symptom of broken or ineffective insulation. Higher energy bills: If you are continuously getting rising heating bills, it could mean that your insulation needs replacing.

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