Cavity Walls - UK Flat Roofing

Homes built after the 1920s had cavity wall insulation structures implemented within their system as a cost-effective way to retain heat back in the day. 

To this day, cavity wall insulation remains one of the most utilised wall insulation across the globe due to its vast number of benefits ranging from cheaper material and fixings to heat retention. 

What is a Cavity Wall Insulation?

A cavity wall insulation refers to the insulation structure that stores heat within the inner walls, ensuring that your home retains heat for longer periods of time by bouncing it back into the room. A cavity wall is made of two separate walls that are thin and commonly have a gap (or cavity) between them - with metal wall ties holding them together.

How To Determine Your Wall Type

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To determine the type of wall you must know the characteristics of each wall type. 

Solid walls

Solid walls are commonly made up of different combinations of materials but are mostly seen as brick walls or bare brick walls fit with a plastered finish. Solid walls are generally very hard with a solid feeling wall, usually made with tiled bricks and stones. 

Dot and Dab walls

Dot and dab walls are comprised of a solid wall complete with plasterboard applied onto the wall itself using “dabs” of adhesive. You can tell whether your wall is considered as a “dot and dab”by running your fingers across the surface of your walls and seeing whether the wall sounds hollow. Typical characteristics of dot and dab walls include a solid feeling wall with slight flexes in certain areas, with a hollow-sounding surface when knocked.  

Plasterboard walls

Plasterboard walls are made with some sort of board material, which are supported by a framework - usually with timber or pressed steel frameworks. Plasterboards will almost always sound hollow when knocking  on them, similar to dot and dab walls. Common materials of plasterboard walls are timber and pressed steel, moisture boards and plywood. 

Benefits Of Cavity Wall Insulation

Cavity wall insulation is possibly one of the most utilised wall insulation types across the world due to its practical advantages. 

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Easy to Install

As mentioned above, houses built past 1920 in the UK likely had cavity walls, and was done so due to the effectiveness of insulation. To this day, cavity wall insulation remains as one of the most popular insulation structures in the UK. The way this insulation is installed is by injecting insulation material (commonly foam) into the cavity from the outside. This process is as easy as it is cheap, which explains its dense popularity for many homes. 

Increased Energy-Efficiency

Using cavity wall insulation ensures that at least a third of all the heat lost with any other wall insulation is saved with proper cavity wall insulation. Through this, it can cut the amount of carbon footprint produced within a home.

Cost-effective Form of Insulation

We’ve explained that the cost of installing this type of insulation is relatively cheap. However, its effects can also save you a lot of money in a long-term basis. Having cavity wall insulation retains heat within your walls, ensuring that heat is locked in. While this can ensure you don’t overuse your heat radiators (or any other source of heat in your home), you can also save a healthy amount of money from your gas bills!

Reduced Heat Loss

Cavity wall insulation slows the movement of heat throughout your walls as mentioned before, and this also means that heating stays for longer. The importance of maintaining an ideal temperature within your home is a great benefit in itself, especially for colder seasons within the UK.

Your Costs/Savings

We have dedicated a separate section for the benefit of cost-effectiveness when using cavity wall insulation as we believe that the price difference between an implemented cavity wall insulation and no cavity wall insulation at all. 

The cost for cavity wall insulation will usually depend on the type of home you have, and the main takeaway from this is that no matter what type of home you have, all homes will receive the same energy efficiency, energy bill savings and heat retention from the initial cost of installation. 

These are the average costs of installing cavity wall insulation in your home: 

Now, when we compare a hypothetical energy bill for a flat with cavity wall insulation, against a flat without cavity wall insulation. Due to heat retention, we can establish that at least one-third of the heat within the flat is retained, meaning that if you pay an average of £520 per year for energy bills in a studio flat, you can effectively save around  £170 in energy costs per year! 

The importance becomes clear for the roofing and construction industry, because of the insulation’s many benefits and cost-effective methods. Due to the rising popularity of greener materials and their utility in different industries, cavity walls are also the optimal choice for sustainability.

Popular Questions on Cavity Wall Insulation:

While this type of insulation has been around for years, there are still some questions that homeowners usually ask themselves before purchasing a cavity wall insulation.

• Is it worth getting cavity wall insulation?

If you want insulation that can save you money, that’s easy to install and can improve your carbon footprint, getting cavity wall insulation is absolutely worth the instalment price. The long-term benefits that cavity wall insulation provides are golden reasons why this type of insulation is a popular choice for many homeowners.

• Are there any disadvantages to cavity wall insulation? 

Dampness is usually a factor that most homeowners should take into consideration when choosing cavity wall insulation, as moisture can diminish the warmth circulating around your home. However, there are plenty of ways to prevent moisture seeping into your cavity walls, such as ventilating your home, installing exhaust fans, and more.

• How long does cavity wall insulation last?

On average, cavity wall insulation can run for around 25 years according to the Cavity Insulation Guarantee Agency (CIGA).

• Does cavity wall insulation cause dampness?

Cavity wall insulation can cause dampness when installed incorrectly (or are in unsuitable properties), but professional installers will often implement these insulation measures effectively.

• Does cavity wall insulation stop mould?

Your cavity wall insulation has a chance of accumulating mould if you don’t correctly weatherproof your house properly. However, cavity wall insulation is also a powerful tool for mould prevention due to its management of temperature and moisture.

• How thick should cavity wall insulation be?

The residual cavity between the insulation and the outer leaf material should aim to be at least 50mm in thickness. The only exception is when there are areas that have severe exposure, whereby a 75mm measured thickness is recommended if the outer leaf is fair-faced masonry.