External vs Internal Wall Insulation: What’s the Best Choice for Your UK Home?

External vs Internal Wall Insulation: What’s the Best Choice for Your UK Home?

Are you thinking about insulating the walls of your home and asking yourself, "External vs Internal Wall Insulation: What’s the Best Choice for Your UK Home?" Effective wall insulation is key to reducing heat loss, lowering energy bills, and decreasing your carbon footprint. With both external and internal wall insulation offering distinct advantages, it can be challenging to decide which option is right for you.

One of our clients, who owns a charming solid wall property in the heart of London, faced a similar dilemma. They wanted to retain the historical character of their home while ensuring it was warm and energy-efficient. After weighing their options, they found the perfect solution that balanced both aesthetics and functionality.

In this article, we'll explore the advantages and drawbacks of each type, focusing on solid wall insulation, to help you make an informed decision for a warmer, more energy-efficient home. Dive in to discover how you can best insulate your solid wall property and enjoy the comfort and savings that come with it.

What Is Wall Insulation?

Wall insulation involves adding an extra layer of material to your property's walls to help retain heat within your home. It offers numerous benefits and plays a crucial role in creating a comfortable living environment by regulating indoor temperatures and reducing heat transfer. Wall insulation contributes to noise reduction, ensuring peaceful interiors, and lowers the carbon footprint by reducing the energy required for heating and cooling. Depending on the type of walls you have, insulation can be added internally, externally, or within the wall cavity itself.

What Are The Different Types of Walls in the UK? 

Understanding the type of walls in your home is essential for selecting the most effective insulation method. Here’s a breakdown of the two most common types of walls in the UK:

Solid Walls

Solid walls are predominantly found in homes built before 1920. These walls consist of either a single or double layer of brick or stone, with no cavity in between.

Insulation Options for Solid Walls: Internal and External Insulation. 

Cavity Walls

Cavity walls are commonly found in homes constructed after 1920. These walls feature an outer and an inner layer with a gap (cavity) in between.

Insulation Options for Cavity Walls: Cavity Wall Insulation.

External vs Internal Wall Insulation: What’s the Best Choice for Your UK Home?

Internal Wall Insulation for Solid Walls 

Internal wall insulation involves adding insulation to the interior walls of your home. This method is used when external wall insulation is not possible. It can be done by fitting insulation panels directly onto the walls and covering them with plasterboard or constructing a stud wall filled with insulating material. 

Advantages of Internal Wall Insulation

  • Cost-Effective: Generally more affordable than external insulation.
  • Soundproofing: Enhances the soundproofing of your property, making it quieter inside.
  • Preserves Exterior Appearance: Ideal for properties in Conservation Areas that need to maintain their original look.

Disadvantages of Internal Wall Insulation

  • Disruption: The installation process can be quite disruptive, involving the removal and reattachment of fixtures.
  • Reduced Room Size: Reduces the size of your rooms.
  • No External Waterproofing: Does not provide an additional waterproof layer around your home.
  • Damp Risks: Poor installation can lead to damp issues. Existing damp problems must be resolved before installation.

External Wall Insulation for Solid Walls

External Wall Insulation (EWI) involves attaching insulation to the exterior of your home. This process includes applying two layers: an insulating layer and an outer layer made from either mineral or synthetic render. In the UK, the most common materials used for EWI are expanded polystyrene (EPS), mineral wool, and phenolic foam. EPS is lightweight, affordable, and offers good thermal performance, while mineral wool is fire-resistant and provides excellent acoustic insulation. Phenolic foam, known for its great thermal performance, is ideal for spaces where thickness is limited. 

Advantages of External Wall Insulation

  • Minimal Disruption: Since EWI is installed on the exterior, it does not disrupt the household or reduce the size of your rooms.
  • Crack and Gap Filling: EWI helps fill in cracks and gaps in the outer walls, reducing drafts and improving energy efficiency.
  • Condensation and Damp Reduction: By insulating externally, EWI can reduce inner wall condensation and dampness issues.
  • Enhanced Weatherproofing and Sound Resistance: EWI improves the weatherproofing and sound resistance of your property.
  • Increased Lifespan of Walls: Protects the brickwork, increasing the lifespan of your walls.
  • Aesthetic Improvement: The facade of your building can be enhanced with a finish of your choice, boosting its curb appeal.

Disadvantages of External Wall Insulation

  • Change in Appearance: EWI will alter the exterior appearance of your property and may require planning permission, making it unsuitable for period and listed properties.
  • Potential for Cold Bridges: If gaps around windows and doors are not properly sealed, this could create 'cold bridges' where the insulation is compromised.
  • Unsuitable for Structurally Unsound Walls: EWI is not recommended for properties with outer walls that are structurally unsound and cannot be repaired.
  • Higher Initial Cost: EWI requires a larger upfront investment.

Investing in insulation is a wise decision to enhance your home's energy efficiency, save on energy bills, and reduce your carbon footprint. Both internal and external wall insulation are effective methods to improve a home's thermal performance. When choosing the right insulation for your home, consider factors such as the age of your property, location, cost of the installation, R-value, and environmental impact.

The advantages of External Wall Insulation generally surpass those of Internal Wall Insulation. EWI offers a lower risk of thermal bridging, minimises the chance of damp issues, and avoids disruptions to your household during installation. It also preserves your internal floor space, making it a highly efficient option for many homeowners.

Ensuring professional installation is essential to maximise the effectiveness of any insulation method you choose.

For expert advice tailored to your home's specific needs, PD Rendering is here to assist. With over 15 years of experience in professional rendering and insulation services, we ensure your property receives the best care. Start your journey toward a more energy-efficient and comfortable home with us today.

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