External Wall Insulation London (EWI) Solid Wall Insulation

What is External Wall Insulation?

External wall insulation is a highly effective method for enhancing the thermal performance of a building, especially in properties with solid walls or those without cavity wall insulation. By insulating the exterior walls you can significantly reduce the heat transfer between the inside and outside of the building, which leads to several benefits.

Energy Efficiency: External wall insulation significantly reduces the heat loss through the walls, which means less energy is needed to maintain a comfortable temperature inside the property. As a result you can experience lower energy consumption and reduced energy bills making it an eco-friendly solution to keep your home warm and comfortable.

Increased Comfort: With improved insulation the indoor temperature becomes more stable, reducing drafts and cold spots. This creates a more comfortable living environment throughout the year, with warmer rooms during the winter and cooler spaces during the summer

Reduced Condensation and Damp: By increasing the thermal efficiency of the walls, external wall insulation can help reduce the risk of condensation and damp inside the property. This is because the insulation raises the internal surface temperature of the walls reducing the likelihood of moisture settling on them

Improved Appearance: External wall insulation is available in a variety of colours, textures and finishes allowing you to customise the appearance of your property. This can significantly enhance the visual appeal of your building and even increase its value

Sound Insulation: In addition to thermal insulation external wall insulation can also provide some sound insulation benefits reducing the amount of noise entering your property from the outside.

Protection and Durability: The reinforced protective layer and topcoat render not only provide a visually appealing finish but also protect the building’s structure from weather damage and deterioration. This can help extend the lifespan of your property and reduce maintenance costs

Although external wall insulation may require an initial investment, the long term energy savings, increased comfort and improved property value make it a worthwhile consideration for homeowners and landlords. Before undertaking an external wall insulation installation it is important to consult with an EWI installer to assess the suitability of your property

External Wall Insulation Installation Process

1- EWI Survey (Pre-Assessment and Measurement) 

The first step in external wall insulation installation involves a thorough assessment of the property to determine the appropriate insulation material and thickness required. This also includes measuring the surface area of the walls that will receive insulation

2- EWI Pre-Installation Requirements 

Before the installation can begin the property owner and EWI installer must identify any supplementary requirements such as the need for additional ventilation or the relocation of external fixtures

3- Condensation Risk Analysis 

A thorough risk analysis will be conducted to identify potential issues that could arise post-installation, such as condensation and dampness. This step helps ensure that the insulation system functions effectively and remains durable

4- Ventilation Enhancements 

If required supplementary services such as extractor fans or trickle vents may be installed to improve the property’s ventilation and reduce the risk of moisture related problems

5- Scaffolding  

Depending on the number of elevations involved, scaffolding may be erected to provide safe access to all areas of the property during installation

6- EWI Pre-installation Wall Preparation 

Before the insulation can be installed, any necessary prep work must be completed, such as repairing damaged walls or removing damaged render

7- Extending Services (Retrofit Properties) 

For existing properties, services may need to be extended to accommodate the added depth of insulation. This could include extending roofs, boiler flues or relocating external fixtures and fittings such as light fittings, alarm boxes, satellite dishes etc

8- Insulation Board Installation 

Mechanically fixing fireproof insulation boards to the exterior of the property is the next step. The insulation boards should be of a suitable material and thickness as determined during the initial assessment

9- Protective Layer Application 

A two-layer protective render is applied on top of the insulation boards. The first layer incorporates a mesh for reinforcement while the second layer serves as a smooth, even surface for the final coat

10- EWI Final Coat Application 

The final coat, chosen by the customer, is applied in the desired finish and colour. This coat enhances the aesthetic appeal of the property and provides additional protection against the elements

11- Finishing Touches 

After the final coat has been applied, new window seals are installed to cover the added depth of the exterior wall, ensuring a watertight seal and an attractive appearance. Any fixtures and fittings removed will be fixed back to the external wall

12- Final Clean up and Paperwork 

Lastly, the installation team will clean up the work area and complete any necessary paperwork to finalise the project. This may include providing warranties, certifications or other documentation related to the insulation system

What are the benefits of External Wall Insulation?

External wall insulation offers a multitude of benefits that enhance a property’s energy efficiency, comfort and appearance.

One of the primary advantages of external wall insulation is its ability to significantly reduce heat loss leading to lower energy bills for homeowners. By minimising the amount of heat escaping through the walls, the insulation helps to create a more consistent and comfortable indoor environment throughout the year

In addition to energy savings external wall insulation also contributes to a reduced carbon footprint for the property. By lowering the demand for heating and cooling, the insulation helps to decrease greenhouse gas emissions making the property more environmentally friendly

During the summer months external wall insulation acts as a barrier against heat keeping the property cool and comfortable. This insulation helps to maintain a stable indoor temperature reducing the need for air conditioning and further contributing to energy savings

Another benefit of external wall insulation is its sound insulation properties. By creating an additional layer on the exterior walls the insulation can help to dampen external noises, making the indoor environment quieter and more peaceful

Aesthetically, external wall insulation can dramatically improve the appearance of a property. With a wide range of colours, textures and designs to choose from homeowners and landlords can customize the look of their property’s exterior to suit their preferences

The low maintenance, self-cleaning render used in external wall insulation systems ensures that the property remains visually appealing with minimal upkeep. This feature helps to save time and money on maintenance costs in the long run

External wall insulation can also positively impact a property’s Energy Performance Certificate (EPC) rating. By improving the energy efficiency of a building the insulation helps to meet the Minimum Energy Efficiency Standards (MEES) making the property more attractive to potential buyers or tenants

How Much Does Installing External Wall Insulation in London Cost?

Determining the cost of external wall insulation involves considering various factors that can influence the overall expense. These factors include:

Size of the property: The larger the property, the more insulation material, labour and time will be required which can lead to a higher cost

Supplementary required works: Depending on the existing condition of the property, additional works may be necessary to prepare the walls for insulation. These preparatory tasks such as repairing cracks or removing old cladding can affect the total cost

Need for scaffolding: In many cases, scaffolding will be required to safely access higher parts of the building. The cost of scaffolding will depend on factors such as the height and size of the property as well as the duration of the project

Access issues and complications: If your property has unique features or challenging access points such as narrow alleyways or uneven terrain the installation process may be more complex potentially increasing the cost

The applied finish: The type and quality of the finish applied to the external wall insulation can also impact the cost. Various finishes are available including render, brick slips, brick effect finish, pebble dash and cladding. The choice of finish will depend on your aesthetic preferences, budget and the desired level of durability and maintenance

To receive a tailored, no-obligation quote for your external wall insulation project please contact our team today. We will assess your specific needs and provide you with a detailed estimate that takes into account all the factors mentioned above.

What Happens After the installation of External Wall Insulation is Completed?

Upon completion of the external wall insulation installation our team takes the necessary steps to register your installation with building control, governing bodies and insurance services. This is done to ensure that all regulations and standards have been met, as well as to secure a 25-year insurance-backed guarantee provided by our insurers SWIGA, for the insulation system. This guarantee is provided in addition to our 2-year comprehensive installer guarantee offering you peace of mind in the long-term performance of your external wall insulation

To maintain the effectiveness of your insulation it is important to follow the recommended maintenance guidelines provided by the installation team. One such recommendation is to periodically repaint the protective layer which may be required every few years depending on the specific product and environmental conditions. Regular repainting not only preserves the insulation system’s performance but also enhances the aesthetic appeal of your home

In addition to routine maintenance it is crucial to monitor the condition of the insulation and promptly address any physical damages that may occur. This includes repairing cracks, sealing gaps or addressing any signs of water penetration or leaks. By doing so, you can prevent potential issues from escalating, ensuring the long term durability and effectiveness of your external wall insulation system

What is the difference between External Wall Insulation (EWI) and Solid Wall Insulation (SWI)?

External Wall Insulation (EWI) and Solid Wall Insulation (SWI) are terms that are sometimes used interchangeably but can refer to different or the same insulation methods. The main difference between the two lies in the type of wall construction being insulated and the location of the insulation

  • External Wall Insulation (EWI): 

EWI refers to the process of applying insulation material to the exterior walls of a building. This method is typically used for buildings with solid walls which lack a cavity and cannot be insulated using cavity wall insulation techniques. EWI involves attaching insulation boards to the outer surface of the walls, followed by a layer of render or cladding to provide a weatherproof, protective finish. However EWI can also be applied to cavity wall constructions in order to achieve better efficiency or Hard To Treat Cavities (HTTCs). These are cavity wall constructions with limited access or other limitations that do not allow the cavity to be insulated  easily

  • Solid Wall Insulation (SWI): 

SWI is a more general term that can refer to insulation techniques applied to solid walls which lack a cavity. SWI encompasses both external and internal insulation methods. As mentioned above EWI is one form of solid wall insulation where the insulation is applied to the exterior of the building. On the other hand Internal Wall Insulation (IWI) is another form of SWI in which insulation is applied to the interior surfaces of the walls. IWI typically involves fixing insulation boards to the internal walls that incorporate a layer of plasterboard to provide a smooth finish

While EWI is a specific method of insulating solid walls from the outside, SWI is a broader term that encompasses both external and internal insulation techniques used for solid walls. The choice between EWI and IWI depends on various factors such as the building’s construction, the property owner’s preferences and any potential disruption during installation.

Another term used when insulating the walls of a property is Hybrid Wall Insulation (HWI). Hybrid Wall Insulation is a term used to describe an insulation system that combines different types of insulation materials or methods in a single application. This approach aims to maximise the energy efficiency and thermal performance of a building by utilising the strengths of various insulation materials or techniques.

A hybrid wall insulation system might involve combining External Wall Insulation (EWI) with Internal Wall Insulation (IWI). A typical example of this would be a semi detached property with either no access to the side elevation or if the side elevation is on a neighbouring property boundary. In this scenario the front and rear elevations can be insulated externally while the side elevation is insulated internally.

Hybrid Wall Insulation (HWI) should be carefully planned and designed by a system specifier as there can potentially be increased risk of condensation and thermal bridging. Techniques such as overlapping the insulation layers are used to minimise this risk.

What other related External Wall Insulation Services do you provide?

Boiler Installation:
We provide a variety of Gas Boiler installations including Heat Only, System Boilers and Combi Boilers. We are experienced and registered installers of all major brands such as Idea, Baxi, Main, Vaillant, Keston and many more.

Loft Insulation :
Installation of loft insulation to reduce heat loss from the roof and increase efficiency of the property.

Smart Heating Controls:
Smart Heating Controls are intelligent thermostatic controls for your heating system. You can remotely control your heating from a smartphone, tablet, or other internet-connected device that is wirelessly connected to the internet. They also help save  money on your heating bills because you have more control over your heating. Additionally, you have individual room temperature control. By not heating unused spaces, you have more opportunities to reduce your heating costs. Most common smart heating controls include thermostats and TRVs

Commercial EPC:
Energy Performance Certificate for office buildings, mixed used, commercial and industrial properties. A certificate required for rental or sale of any commercial property.

Residential EPC:
An Energy Performance Certificate (EPC) is a document collated from an energy assessment of a property to outline how efficiently the property performs in energy consumption and heat retention. Similar to the  multi-coloured labels now seen on new appliances,  EPCs advise how energy efficient a building is and give it a rating from A (very efficient) to G (inefficient). In the UK an EPC is a legal document required to rent or sell your property.

Frequently Asked Questions

Is external wall insulation appropriate for all kinds of properties?

External wall insulation can be used in a variety of properties including detached, semi-detached, and terraced dwellings. It may not, however, be appropriate for all types of buildings, such as those with a cavity or certain types of construction.  Contact us today to discuss your requirements in further detail

How much will external wall insulation save me on my energy bills?

The amount of money you save on your energy bills with external wall insulation will vary depending on the characteristics of your home and your energy consumption habits. In addition with the current unpredictability of energy prices it could be very hard to determine, but typically you are expected to save in excess of £500 per year.

What is the lifespan of external wall insulation?

The lifespan of external wall insulation is determined by the materials used and the state of the protective layer. External wall insulation, in general, can last for decades before needing to be replaced.

Do I require planning permission to install (EWI) on my property?

This can vary from council to council and it is best to communicate with your local planning officer for more information.

Can I install External wall insulation (EWI) on a listed building?

External wall insulation (EWI) is generally not permitted on listed buildings in the UK. This is because listed buildings are legally protected due to their historical or architectural significance, and any alterations or modifications must be done in such a way that the building’s character and special interest are preserved. The local planning authority must approve any changes to the exterior of a listed building, including the installation of EWI.

It should be noted that each listed building is unique and has its own set of rules and regulations. If you intend to make any changes to a listed building, you must speak to your local planning department.

In some cases and depending on the individual building an alternative to insulate the property internally (Internal Wall Insulation) may be approved

Can I install External wall insulation (EWI) in a conservation area?

External wall insulation (EWI) can be installed in a conservation area, but you must follow certain guidelines and most likely obtain planning permission from the local authorities. It is critical to preserve the character and appearance of conservation areas, and any changes to the exterior of buildings must be carefully considered.

If you intend to install EWI in a conservation area, you should first research the specific guidelines and requirements that apply to your location. . It is also a good idea to consult with the lo0cal planning department before applying for a planning application. They will be able to advise you on the best approach for your situation and ensure that the installation is done in accordance with the conservation area guidelines.

How long does external wall insulation take to install?

The time it takes to install external wall insulation will vary according to the size and requirements of your property. In general, the installation process can take anywhere from a few days to two weeks for a single dwelling.

What is the thickness of the External Wall Insulation (EWI) system added to my property?

Generally external wall insulation adds 96-100 cm to the exterior of the property, this includes 90mm thick insulation board and approximately 6-10mm thickness of the render layers. Whilst 90mm insulations are typically required to achieve the 0.3 U-value (currently required by building control) other thicknesses of board can be used where 90mm would not be suitable.

What happens if some of my external walls are not accessible for EWI?

In some instances external walls may not be accessible due to neighbouring boundaries or structures. Leaving these walls uninsulated can cause heat loss, cold bridging and condensation, therefore it is not a good idea to ignore. Where an external wall is not accessible it may be suitable to combine a mix of internal wall insulation and external wall insulation to overcome these issues.

Is it possible to install external wall insulation during the winter?

Yes, it is possible to install external wall insulation during the winter but this would depend largely on the temperature and weather condition. The render applications typically cannot be applied in wet conditions or low temperatures (usually below 5 Degrees C). It would be best practice to avoid installation during the cold winter months.

Can external wall insulation increase my home’s value?

External wall insulation can, in theory, increase the value of your home. External wall insulation can make a building more appealing to potential buyers by improving its energy efficiency.

What are the various types of protective layers for external wall insulation?

Self colour render, brick effect render, pebble dashing, and brick cladding are common types of protective layers used for external wall insulation. The best option for your home will be determined by the building’s specific characteristics as well as your personal preferences.

How do I keep my external wall insulation in good condition?

It is critical to follow any recommended maintenance guidelines, such as repainting the protective layer every few years, to keep your external wall insulation in good condition. It is also critical to address any issues with the insulation as soon as they arise in order for it to continue to function properly.

How frequently should I have my exterior wall insulation checked?

It is generally recommended that your external wall insulation be inspected every few years to ensure that it is properly and effectively functioning. This may vary depending on the type of insulation and protective layer used, as well as the condition of your home.

What are the types of wall insulation?

The most effective type of external wall insulation will depend on the specific needs and characteristics of your home. It is generally a good idea to choose a high quality insulation material and protective layer from a reputable manufacturer such as Weber. We recommend the Weber XM external wall insulation system for most of our projects. 

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