What Are The Problems With External Wall Insulation?

What Are The Problems With External Wall Insulation?

External wall insulation can be a great way to improve the thermal efficiency of your property and reduce your energy bills.

However, problems can occur if it is not installed correctly.

But since insulating an external wall can prevent up to 40% of the heat lost from a property, it is worth considering.

For the investment, you will have a home with no draughts, a fresh exterior appearance, and lower heating bills.

Not only will you see your home’s energy rating improve – but there could also be a 10% boost in your home’s value.

Here, the Property Road team takes a closer look at the pros and the problems with external wall insulation, which will help if you:

  • Are looking to buy a property that already has it;
  • Want to add it to your existing property.

What is external wall insulation?

External wall insulation is a system used to insulate the external walls of a property.

It is usually applied to properties with solid walls; however, it can also be used on properties with cavity walls – see below.

The insulation material is applied to the outside of the property and is held in place with either adhesive or mechanical fixings. A render or cladding is then applied over the top of the insulation to provide a weather-proof finish.

Why would you have external wall insulation?

There are several reasons why you might want to have external wall insulation installed on your property, such as:

Improving your home’s thermal efficiency

This can help to reduce your energy bills as you will need to use less heating and hot water to maintain a comfortable temperature inside.

Reduce noise pollution

The insulation can help reduce the amount of noise that comes into your property from outside, making it more peaceful and quieter.

Improve the appearance of your property

Having insulation can give your property a facelift as it can be finished in a variety of colours and finishes.

What are the advantages of external wall insulation?

External wall insulation has pros and cons – here are some of the advantages:

  • Reduces heat loss and energy bills;
  • Fewer draughts;
  • No disruption when being installed;
  • Does not reduce the internal floor area;
  • Insulated walls will contribute to thermal mass (also known as the ‘tea cosy’ effect);
  • Improves weatherproofing and sound resistance;
  • Boosts the life of the wall;
  • Reduces condensation on internal walls.

What are the disadvantages of external wall insulation?

External wall insulation can have some disadvantages, such as being difficult to install.

Having looked at the advantages, the problems with external wall insulation include:

  • It can be difficult to install;
  • If not installed correctly, it can cause damp problems;
  • It can be expensive.

Common problems include damp patches appearing on walls, mould growth, and cracking or bulging of the render or brickwork.

Problems can also occur if the insulation is not properly protected from the weather, or if it is installed on a property that is not suitable for it.

To avoid problems with external wall insulation, it is important to choose a reputable installer who has experience in installing this type of insulation.

It is also important to make sure that the property is suitable for external wall insulation, and that all precautions are taken to protect the insulation from the weather.

So, when weighing up the pros and cons, insulating your external wall is a good option if you are looking to improve the thermal efficiency of your property.

However, it is important to ensure that it is installed correctly to avoid potential problems.

What are the common problems with external wall insulation?

External wall insulation can cause several problems, including:

Water ingress

Water ingress is often the biggest problem with external wall insulation, as it can lead to serious structural damage. It is important to make sure that the insulation is properly installed and that any gaps are sealed.

Structural damage

Structural damage can also be caused by the insulation if it is not installed properly.

Thermal bridging

Thermal bridging can occur if the insulation is not installed correctly, and this can lead to heat loss and cold spots on the property.

Condensation and mould growth

Condensation can also be a problem with insulation, as it can cause mould growth. It is important to ensure that the property is well ventilated to prevent this from happening.

Fire safety

Fire safety is another important consideration when installing external wall insulation. It is important to make sure that the insulation does not block any fire exits or windows.

While insulating a property’s external wall can cause several problems, it is important to note that these can be avoided if the insulation is installed properly.

How much does external wall insulation in the UK cost?

In the UK, external wall insulation can cost between 5000 and 15000 pounds.

The cost will vary depending on the size of the property and the type of insulation that is used. It is important to get a few quotes from different companies before deciding.

  • For a three-bedroom semi-detached home, the cost is likely to be in the range of £5,000-£9,000.
  • Larger detached homes could cost £8,000-£15,000 and there are specialist systems that come with a higher price tag, but there are also cheaper options available from builders’ merchants.

Either way, scaffolding will need to be erected, and all pipes and cables fixed to the wall will need to be removed and replaced – costs that cannot be avoided.

But is it worth the expense?

According to the Energy Saving Trust:

  • The owner of a mid-terrace home would save £160 per year for an external wall insulation bill of £6,000.
  • A semi-detached owner would pay £10,000 and save £255 per year.
  • A detached home would cost £14,000 to insulate but save £425 on average.

External wall insulation FAQs

How much difference does external wall insulation make?

The difference that the insulation will make to your property depends on several factors, such as:

  • The type of material used;
  • How well the insulation is installed;
  • The type of property you have.

What is the best insulation for outside walls?

Several different types of insulation material can be used, including:

  • Polystyrene (EPS);
  • Polyurethane;
  • Phenolic resin (K5);
  • Mineral wool;
  • Wood fibre.

Each type of insulation has its own benefits and drawbacks, so it is important to choose the right one for your needs. For example, polystyrene is a good choice if you are looking for a lightweight insulation material, but it is not as durable as other options.

Can too much external wall insulation cause condensation?

If the insulation is too thick or not installed correctly, it can cause condensation to form on the inside of the property. This can lead to damp problems and is something you should be aware of before installing external wall insulation.

Can you put external wall insulation on a cavity wall?

Yes, insulation can be used on both solid and cavity walls.

However, if you have a cavity wall, it is important to make sure that the cavity is filled with insulation material before having the external layer installed to prevent any heat loss through the cavity.

Can external wall insulation damage health?

As far as medical research goes, there are no signs that external wall insulation can be harmful to our health.

There is no evidence to suggest that external wall insulation can damage health. However, it is important to make sure that the property is well ventilated to prevent condensation and mould growth.

Will external wall insulation last?

External wall insulation should last for many years, provided it is installed correctly and maintained properly.

Is it difficult to get planning permission for external wall insulation?

Planning permission is not usually required for external wall insulation. However, it is always best to check with your local planning authority before starting any work – especially if it drastically changes the appearance of your home.

How to find reputable companies?

There are several ways to find reputable companies that can carry out external wall insulation. One way is to ask friends or family if they have used a company before. Another way is to search online for customer reviews. Finally, it is always best to get a few quotes from different companies before deciding. Also, don’t forget to check online reviews.

Problems with internal wall insulation

It’s also worth noting that there are issues to consider for problems with internal wall insulation, including:

  • It can be difficult to install in older properties;
  • The installation process can be disruptive;
  • Might not be suitable for listed buildings or those in conservation areas.

We mentioned earlier the problems with cavity wall insulation, and these could include:

  • If the property is not properly ventilated, there is a risk of condensation and mould growth.
  • If the cavity wall insulation is installed incorrectly, it can cause problems such as damp patches on walls or a decrease in the property’s thermal efficiency.
  • The cavity wall insulation process can also be disruptive.

If you need to decide between insulating your home with either internal, external, or cavity wall insulation, you really should speak with experts to calculate the costs, the amount of disruption – and the downsides – before committing yourself.

What are the problems with external wall insulation?

External wall insulation can provide several benefits to your property, but it is important to make sure that it is installed correctly to avoid any problems.

If you are thinking about insulating your external walls, you must use a professional company with a sound reputation. For the money, it’s important to do your research and ensure you don’t waste money – or face the prospect of having to remove the insulation.

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