What is an alternative to cavity wall insulation?

Author: Zaria Simonis  |  Last update: Monday, March 24, 2025

The two main alternative wall insulation approaches for solid walls are internal wall insulation and external wall insulation. Both insulation approaches are slightly more complex than cavity wall insulation, but just as effective in retaining home heat and improving efficiency.

Is there an alternative to cavity wall insulation?

To counter these problems, external wall insulation offers a superior solution. Unlike cavity wall insulation, external systems create a thermal envelope around the building, preventing heat loss and reducing the risk of condensation.

How to insulate walls without a cavity?

Here's your to-do list to externally insulate any wall without a cavity:
  1. Step 1: Prep the Surface. Clean the exterior surface you'll be working on. ...
  2. Step 2: Install Insulation Boards. ...
  3. Step 3: Cut and Shape Insulation. ...
  4. Step 4: Apply Base Coat and Mesh. ...
  5. Step 5: Apply Finish Render.

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.

What is the cheapest way to insulate cavity walls?

Here are the three cheapest ways to insulate internal walls:
  • Insulation Boards. Insulation boards are a popular choice for internal wall insulation because they are relatively affordable and easy to install. ...
  • Battening the Walls. ...
  • Building a Stud Wall.

Secrets Behind Cavity Wall Insulation Failures Revealed

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.

What is the least expensive way to insulate a house?

It's essential to wear protective clothing and a mask when installing fibreglass insulation to prevent any health risks. Overall, fibreglass insulation is the cheapest and most effective insulation option available, making it a popular choice for homeowners and builders alike.

What is the downside to cavity wall insulation?

This means that there will be a moisture build up in your walls. The moisture will transfer to your cavity insulation, and damp and mould will begin to develop inside your walls. This really does become a hindrance for you when the mould starts growing inside your home, and damages your things.

How often should cavity wall insulation be replaced?

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.

What happens to cavity wall insulation after 25 years?

The majority of cavity wall insulation should last at least 25 years, but alterations to the outer walls of a house may cause it to break down and degrade earlier than that, which can increase cold air, damp issues and heat loss in a home as well as possible health problems.

How do you insulate a cold wall from the inside?

Internal wall insulation is done by fitting rigid insulation boards to the wall, or by building a stud wall filled in with insulation material such as mineral wool fibre. Internal insulation: Is generally cheaper to install than external wall insulation.

Can no cavity wall insulation cause damp?

In cases where the cavity is left open, moisture can condense into the loft to cause dampness and mould issues. Sometimes other measures like trickle vents for windows should be installed prior to installation to compensate for increased thermal efficiency.

What are the downsides of external wall insulation?

8 disadvantages of external wall insulation types
  • Impermeability. One of the main disadvantages of external wall insulation boards is impermeability. ...
  • Size. ...
  • Cost. ...
  • Insulation issues. ...
  • Irritation to skin and respiratory system. ...
  • Weight. ...
  • Limited insulation value. ...
  • Environmental impact.

How do you insulate a wall without cavities?

Two options are available for non-cavity walls: external insulation (around £12,000) and internal insulation (about £7,500). While expensive, government schemes like the Great British Insulation and ECO4 offer grants to help low-income households improve their homes' energy efficiency.

Is it worth replacing cavity wall insulation?

Old or failing cavity wall insulation can lead to several consequences, including decreased performance, health issues due to mould and pest infestations, and expensive repairs. To avoid these issues, homeowners should proactively address their insulation maintenance needs.

What is the best cavity wall insulation for old houses?

Best Cavity Wall Insulation for Old Houses: Complete 2025 Guide
  • Mineral wool is the best option for old homes, followed by polystyrene beads and polyurethane foam which are easier to retrofit.
  • Not all older homes are suitable for installing insulation as some might not have adequate infrastructure.

Can you get rid of cavity wall insulation?

It is possible to remove a range of cavity wall insulation types, including mineral fibre, expanded polystyrene beads, and polyurethane foam. You can also get older urea-formaldehyde foam removed. This is a job that will require professional equipment.

Does cavity wall insulation make a big difference?

About a third of all the heat lost in an uninsulated home escapes through the walls. By properly insulating cavity walls, you will save energy and cut costs off your heating bill.

When should you not have cavity wall insulation?

The two most common issues with cavity walls that would deem your house unfit for insulation are; the amount of rubble and dirt gathered in your cavity wall, and the actual width of your cavity.

What is the best insulation for interior walls?

Best Insulation Type for Interior Walls
  • Fiberglass batts: Affordable and easy to install in open walls.
  • Blown-in cellulose: Great for retrofitting existing walls with minimal disruption.
  • Spray foam: Provides excellent air sealing and insulation in one application.

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.

How much does it cost to insulate a 2000 sq ft house?

The cost to insulate a 2000-square-foot house can range from $2,000 to $6,000, depending on the type of insulation used and other factors.

What time of year is insulation cheapest?

Best Time of Year to Buy Insulation

In this case, the spring is the best time, because you will also start to see savings in the summer months. The same is true for warmer climates, just different times of year because you'll want the job finished before the heat sets in.

How can I insulate my house without tearing down the wall?

The best materials for the job are: Cellulose insulation: Cellulose is typically made from recycled newsprint and comes in a loose fill form that is blown into wall cavities till it is densly packed. It provides great thermal resistance and is particularly well-suited to retrofits.

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