External wall insulation is a highly effective way to improve the energy efficiency of your home while also enhancing its appearance.
Here, Matthew Woodhams, Technical Specification Manager at Baumit, answers some of your questions about external wall insulation.
What is External Wall Insulation?
External wall insulation (EWI) involves the application of insulation materials to the outside face of your exterior walls. EWI systems typically consist of insulation boards, fixings, and a protective, decorative finish such as render or cladding.
What are the benefits of External Wall Insulation?
Insulating external walls offers numerous benefits. Firstly, it significantly reduces heat loss through the walls, resulting in lower energy consumption and reduced heating bills. The exterior wall insulation also helps to regulate the internal temperature, for example, during the hotter summer months, creating a more comfortable living environment throughout the year.
Does external wall insulation increase the value of my home?
External wall insulation improves the thermal performance of your home, which can lead to a higher Energy Performance Certificate (EPC) rating. This rating is an influential factor when selling a property and can increase its value. Additionally, EWI improves the appearance of your home, with a wide range of finishes available to enhance its aesthetic appeal.
What are the different types of External Wall Insulation?
There are several types of external wall insulation available. The best external wall insulation depends on your specific objectives and its intended purpose. The most common types include:
Expanded Polystyrene (EPS): This type of insulation is lightweight, cost-effective, and easy to install. EPS insulation boards are available in various thicknesses to suit different requirements. Breathable EPS is a good choice because it allows the walls to breathe, avoiding trapped moisture inside the home and creating optimal living conditions. EPS is also a popular choice due to its affordability and ease of installation, whilst providing excellent thermal insulation.
Mineral Wool: Made from non-combustible, breathable mineral wool fibre and offering excellent thermal performance. It is also breathable, allowing moisture to escape to the outside.
Wood Fibre: Wood fibre insulation is a natural, breathable option that maintains the moisture balance of your property. As well as having good thermal insulation properties this system also improves sound insulation.
Other synthetic: Materials such as PIR (Polyisocyanurate) and PUR (Polyurethane) offer good levels of insulation but are vapour closed, which can slow down the vapour transmittance from inside the property, to the outside.
Why is it important to choose breathable Exterior Wall Insulation?
Breathable external wall insulation helps reduce condensation inside the home by allowing moisture from everyday activities such as cooking and bathing to escape to the outside. Non breathable insulation for external walls can inhibit the ability of this moisture to escape leading to serious issues with interstitial condensation within the wall structure itself, along with dampness, mould and rot..
Is planning permission required for external wall insulation
In most cases, insulation for external walls does not require planning permission. However, there are exceptions, such as properties located in conservation areas or listed buildings. It is essential to check with your local planning authority to determine if any restrictions apply to your property.
It is always recommended to consult with a professional installer who can guide you through the process and ensure compliance with local regulations.
Will external wall insulation affect the appearance of my home?
External wall insulation actually enhances the appearance of your home. There are various finishes available, including renders, cladding, and brick slips, which can be customised to match your desired aesthetic.
How much can I expect to save on my energy bills with external wall insulation?
The exact amount of energy savings will depend on various factors, such as the insulation thickness, the existing condition of your walls, and your heating habits. However, according to the Energy Saving Trust, external wall insulation could save you around £255 a year. The average saving is based on a typical three bedroom semi-detached house with gas central heating and an average gas price of 3.80p/kWh – savings vary depending on the size of your house, the amount of external walls you have and what type of heating you have
Is external wall insulation suitable for all types of properties?
External wall insulation is most commonly used and most effective for properties with solid walls, including both brick and concrete constructions. It can also be suitable for cavity walls, non-traditional properties, and extensions. However, it is essential to consult with a qualified installer to assess the suitability of your property and determine the best insulation solution.
What advice would you give to homeowners considering external insulation?
Remember that external wall insulation is an investment in the future of your home, providing both financial savings and environmental benefits. By adding insulation to the exterior walls, you can reduce heat loss, lower energy bills, and enhance the appearance of your home. With various insulation materials and finishes available, you can choose a solution that meets your specific requirements and aesthetic preferences.