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Is Cavity Wall Insulation Good or Bad?


Is cavity wall insulation good or bad? First off, what is a cavity wall? These structures consist of two layers or ‘shells’ of brickwork, separated by a gap.

This gap contains nothing but fresh air to improve the thermal qualities of your home. How does this happen? Well, heat transfer does not happen as quickly over air as it does through a solid or damp substance.

The vast majority of new houses today are built with cavity walls as they prove to be twice as efficient as solid walls when it comes to thermal quality.

It makes sense – two walls being twice as efficient as one! A solid wall is exactly that – a solid wall that allows heat to travel through the brickwork, directly to the outside space.

So a cavity wall already features an element that makes it incredibly thermal efficient – why would you bother adding extra insulation? And is cavity wall insulation good or bad? First, let’s talk about the two types…

Insulating the Gap Within the Wall

As it is traditionally known, cavity wall insulation is the process of retrofitting wall insulation material that is injected or blown into the space between the inner and outer shell of your walls.

This fills the gap or the cavity with an extra layer of material that is supposed to reduce the amount of energy lost through your walls.

As this is a retrofit operation, the process is done blindly. Holes are drilled in strategic places within your exterior brickwork, and then hoses are inserted into the holes. The material is then blown into the gap, with the hope that the entire area will be filled.

It is impossible to truly guarantee that every hole and space has been filled, as it is impossible to see through the brickwork. This could create cold spots that significantly reduce the thermal efficiency of this operation.

Even if successful, many experts argue that cavity wall insulation promotes the transfer of moisture between your inner and outer shells, again reducing its thermal efficiency.

Is Cavity Wall Insulation Good or Bad

External Cavity Wall Insulation

External insulation is the process of applying a material to the exterior of your house that helps to prevent heat loss, or moisture gain.

This is much more effective than insulating the gap in-between a cavity wall as you can actually see what you are doing!

By applying external wall insulation to your home, you can ensure your house is wrapped up in insulating material like a big warm jacket – creating all-encompassing thermal efficiency.

This will help to minimise cold bridging too, which is the transfer of cold air through your masonry.

Home Logic Wall Insulation is the best alternative to traditional cavity wall insulation methods. This product creates an invisible layer of protection on the outside of your home that can reach up to 17mm into your substrate. This significantly reduces water absorption and heat transfer away from your property.


Is Cavity Wall Insulation Good or Bad?

So is cavity wall insulation good or bad? The answer all comes down to the method of insulation you are applying!

Internal cavity wall insulation is not advisable as you can never guarantee the best results. The jury is also still out on this method’s practicality too, in terms of its effectiveness to combat moisture.

Filling the gap between the two layers of brickwork creates a bridge for moisture, heat and mould to travel. The gap is there for a reason – leave it that way!

However, external wall insulation is definitely worth considering. It is a touch more expensive than internal cavity wall insulation methods, but the benefits last up to 20 years.

Our exterior wall insulation product is one of the best, if not the best, available product on the market. It will protect your property from water absorption, dirt, debris and heat loss all year round.

Book a free site survey today, obtain a no-obligation free quote and see if external wall insulation is something that may help you save money. You can contact us for more information if you like by calling 0800 1700 636.