Private Homeowners / Landlords
Support for Private Homeowners / Landlords
If you’re looking for ways to reduce fuel bills and to improve the appearance and value of your property, then Permarock external wall insulation systems could be the perfect solution. When you choose our products, you benefit from over 40 years’ experience, and can be assured of industry-leading quality and value.
If you are thinking about having external wall insulation fitted to your home, we’ll be happy to put you in touch with one of our registered installers, who will be able to guide you through the process.
An Introduction to External Wall Insulation (EWI)
If your home was built before 1919, its external walls are probably solid. In other words, it probably doesn’t have cavity walls. Cavity walls are made of two layers of construction with a small gap or ‘cavity’ between them. Where a cavity exists, insulation can often be installed in the cavity space, subject to a suitability survey. However, by contrast, solid walls have no cavity, so options to insulate them are restricted to either insulating internally or externally. Permarock supplies external wall insulation.
Adding insulation to the outside of your home has a ‘thermal jacketing’ effect, keeping more heat in during the winter and keeping your home cooler during the summer months. It helps to reduce temperature fluctuations throughout the year and maintains a more comfortable internal living environment, with less risk of cold, damp and mould.
Put simply, the better-insulated you can make your property, the less money you’ll spend on heating and maintaining it.
Systems and Colour Choices
We offer a wide range of insulation systems, renders and decorative effects. Your Permarock Registered Installer will be able to talk you through your options – in terms of cost, colour and surface texture. Some systems are better suited than others to certain circumstances and property designs. Again, your installer will be able to advise you about which options should work best for your home.
Planning Requirements
External wall insulation can sometimes change the appearance of a property, so planning permission may be required. This is particularly relevant in conservation areas and for listed buildings. Advice should be sought from your local planning office before starting any works.
If you insulate a solid wall, you will also have to make sure that it complies with the current Building Regulations in relation to the thermal performance of your property. As a rough guide, you will need at least 90 mm of insulation to achieve this, dependent upon which insulation material is used. You should also be mindful that the overall external wall insulation system depth will exceed the insulation thickness by an additional 15-20mm (dependent upon specification).
Your chosen installer will be able to advise you on the thickness of insulation required, and assist with any requirements to progress your installation.
The Installation Process
EWI is fitted to the outside of the property, so it won’t reduce the size of your internal living spaces and the work itself isn’t very disruptive. A certain amount of work might be needed to extend pipes, and flues, but the great majority of the work will take place outside.
Drilling may cause occasional noise but your daily routines shouldn’t otherwise be affected. You should not be left without services (power, water etc.) at any time during the works, except very limited periods where works to extend boiler flues, pipework etc. are required.
Timescale
Allowing for normal weather conditions and preliminary works, the installation of an external wall insulation system on a typical semi-detached house can take between 3 and 5 weeks, but this can be longer in winter months or if severe weather causes delays. Similarly, if additional enabling works or structural repairs are required, this timeframe is likely to be extended.
Additional Home Improvements
If you are planning any other improvements (such as new windows, extensions, etc.) it is advisable to undertake these works before installing the external wall insulation. Your registered installer will be able to assist you accordingly.
Guarantees and Aftercare
Permarock provides a 10 year material guarantee on every project. For schemes funded by the Government, options are also available for a 25 Year independent guarantee such as the Solid Wall Insulation Guarantee Agency (SWIGA) Guarantee.
These guarantees provide additional peace of mind and access to technical expertise in the event of any defect in design, workmanship or materials. Your installer will be able to offer you additional information and advice on the range of guarantees available to you.
Your installer will also issue you with an ‘Aftercare’ booklet detailing how maintenance can be carried out for routine tasks such as cleaning, minor repairs, and either modifying or adding new fixtures and fittings, such as hanging baskets, satellite dishes, etc.
FAQ’s | External Wall Insulation
What is External Wall Insulation (EWI)?
EWI involves applying an insulating layer to the exterior walls of a building, followed by a protective render or cladding. This helps improve thermal performance, reduce energy consumption, and enhance the aesthetic appearance of the building.
What are the benefits of External Wall Insulation?
- Improved energy efficiency by reducing heat loss through the walls.
- Lower energy bills due to enhanced thermal performance.
- Increased property value and improved external appearance.
- Better internal comfort, keeping homes warmer in winter and cooler in summer.
- Reduction of condensation and damp issues by improving wall breathability.
How does EWI affect U-Values?
U-Values measure the rate of heat transfer through a building element, such as walls. EWI reduces the U-Value by adding insulation, resulting in better thermal efficiency. The lower the U-Value, the more energy-efficient the wall becomes.
What types of insulation materials are used in EWI systems?
Common materials include:
- Expanded Polystyrene (EPS): Lightweight and cost-effective, with good thermal insulation properties.
- Mineral Wool: Offers excellent fire resistance and soundproofing qualities.
- Phenolic Foam: Provides superior insulation with a thinner profile, ideal for space-constrained areas.
- Wood Fibre: A more sustainable option, often used in eco-friendly construction.
How thick should the insulation be?
The thickness of the insulation depends on building regulations, desired U-Values, and the insulation material used. For example, to achieve a U-Value of 0.3 W/m²K (common in the UK), the insulation thickness might range from 100mm to 200mm, depending on the material’s thermal performance.
Can EWI be applied to all types of buildings?
EWI is suitable for most types of buildings, including solid-wall properties, older homes, and commercial buildings. However, it may not be suitable for listed buildings or those with complex architectural features. Always check local planning and building regulations.
How long does External Wall Insulation last?
When properly installed and maintained, certificated EWI systems can now last up to 60 years. Regular inspections and occasional maintenance (such as cleaning or repairing damaged render) can extend the lifespan.
Will EWI affect the appearance of my home?
Yes, but in a positive way. EWI systems are usually finished with a decorative render, which comes in a variety of colours and textures. This allows homeowners to improve their building’s appearance while adding insulation.
Do I need planning permission for EWI installation?
In most cases, EWI installations on existing properties do not require planning permission. However, for listed buildings or properties in conservation areas, planning consent may be required. Always consult your local planning authority.
Can EWI help reduce noise?
Yes, EWI can provide some soundproofing benefits. Insulation materials like mineral wool are particularly good at absorbing sound, which can reduce external noise, especially in urban areas.
How much does External Wall Insulation cost?
Costs vary depending on factors such as the size of the property, insulation material, and complexity of installation. On average, EWI systems can cost between £80-£100 per square metre, with larger projects often having economies of scale.
What grants or funding are available for EWI?
In the UK, some homeowners may be eligible for funding through schemes like the ECO (Energy Company Obligation) or Warm Homes: Local Grant which subsidise energy efficiency improvements. Check with local energy providers and government schemes for available support.
How long does it take to install External Wall Insulation?
The installation time depends on the property size and complexity. A typical three-bedroom semi-detached house can take 3-5 weeks for installation, including preparation, insulation, and rendering.
Will EWI fix damp problems?
EWI can help reduce condensation by keeping walls warmer and improving breathability, but it may not fix pre-existing rising or penetrating damp. Any damp issues should be addressed before EWI installation.
Can External Wall Insulation be combined with other insulation methods?
Yes, EWI can be combined with other methods like cavity wall insulation or internal wall insulation for improved thermal performance, especially in properties with mixed construction types.
