What is External Wall Insulation (EWI)? External wall insulation (EWI) is a layered insulation and render which encases a property and helps improve energy efficiency. This layered method encases the property and helps prevent heat from escaping unnecessarily, containing it within the property. By minimising heat loss in cold weather and heat gain in warm weather, EWI creates a much more comfortable living environment and reduces heating costs.
How is EWI installed? EWI starts with a survey of your home to determine any planning requirements/building regulations to be met, if any work needs to be completed prior to having the insulation boards attached (for example, any loose render needs to be removed, if any areas need to be built up/repaired to appropriately install the system) and note any enabling works.
Because the insulation boards are a Styrofoam material, they do not hold weight. For this reason, any pipes, decorative finishes to the home, satellites, gates, etc. will need to be attached to wooden blocks. The blocks are attached to the home and the insulation is applied around them. Once the work is complete, all items are reattached to the secure anchor blocks and continue to be a part of your décor.
During the survey, we will also look for thickness of walls, any vents that need to be drilled, as well as flues and pipes that need to be installed. If there are any utilities that need to be moved, we will contact the services (such as telephone and electric) to inform them we are installing EWI and request they move any lines if necessary. If any gas works need to be completed, we will either use one of our trusted, vetted sub-contractors or you can choose to hire out the work yourself.
Once the property is measured and any other costs are taken into account (repairs, building works, scaffold, planning fees, etc.), we will present you with an estimate and arrange to discuss it. If you choose to accept the estimate, works will be scheduled to begin. An average 80 square metre house will take approximately 7-10 days depending on weather, utility companies and planning permission if necessary. With the systems we install, weather can be an issue as we will not apply base coat, primer or render when it is raining, forecast for moderate to heavy rain or at a temperature of 5 degrees centigrade and falling. As with all our work, we will keep you informed and remain in contact to discuss scheduling and access. As the work is done to the exterior of your home, there should be little disruption to the inside of the home and no loss of internal space.
After the building works and enabling have been completed to a satisfactory standard (our work is signed off by a site supervisor after each stage of the installation process), the next step is to attach insulation boards and track. Depending on the system chosen, the boards are attached either with an adhesive and/or a mechanical fixture. Other than building works, this is the most disruptive portion of the installation as far as noise is considered. The workers install the boards by drilling holes in the outside wall and then screwing in special fixtures. The fixtures come in different lengths which is why wall thickness is reviewed during a survey. The boards typically meet up smoothly, however occasionally there are small gaps which are filled in with insulation foam. Many homeowners report noticing a difference in the temperature of their home as soon as the boards are installed.
The second stage is to apply the mesh and base coat. This layer will then receive the primer which will prepare the surface for the final render. Finally, the render is applied. Depending upon the system chosen, there are multiple finishes and colours to choose from. Options include solid colour render, decorative finishes/touches to the render, a pebble dash system or brick effect/brick slip systems. The cost of the different finishes varies as some non-standard colours are more expensive from the manufacturer and some finishes, such as brick effect are more time intensive and laborious so will therefore come at a slightly higher cost. The outcome, however is very similar to real brick and due to planning in some areas will be the only option available. It is possible to have a specialist finish on one area of your home (such as the front) and solid colour render on the remainder. It is also possible to insulate only the sides and back of homes if the front of your home is stone or planning will not allow the façade to be changed.
The final stage is to reattach all outside items, realign satellite dishes and clean up any overspills, drips, etc and remove all rubbish. We do cover areas under the render as well as plants and tape up windows, however sometimes spills happen. Our goal is to leave your home more beautiful and energy efficient than when we came.
We will take photos at each stage of the installation and upon the completion of the works, provide them to you, along with manufacturer maintenance information and copies of any building notifications, planning, etc. relating to the EWI installation at your home. We are also available to you for questions and concerns indefinitely after works have been completed.
Is EWI suitable for my property? EWI is typically installed to insulate solid wall properties, brick, stone and concrete. It can, however be used to improve the performance of cavity walls (particularly difficult to insulate cavity walls) and non-traditional construction. If your home was built before 1920, it is most likely solid wall construction. The majority of terraced housing in the UK are solid wall construction. You can usually find this information in your deed, by measuring the wall thickness at an opening (window or doorway) as solid walls measure in the region of 225mm thick
If you live in a mid-terraced property, it is possible to install EWI even if your neighbours on either side choose not to by providing a ‘stop end' at the edge of your boundary. Additionally, if there isn't enough room under the sills and roof overhang on your property, overcills and roof profiles can be used or it may be possible to extend the roof. These are all questions you can discuss with us when we survey your property.
Do I need planning permission for EWI? As EWI covers the whole of the outside of your property, it is likely to change its appearance and you should ask your local authority planning department whether planning permission is required to install EWI. Planning permission typically is not required and is acceptable under permitted development if the final wall covering reflects that of the existing building. i.e. if the existing is a dry dash finish, the new finish should be dry dash. If the new finish varies from that on the existing building, then it is likely planning permission is required. Planning permission is generally required if the property is within a conservation area or another designated area.
In a local conservation area, the decision will depend upon the planning constraints of the particular conservation area. Your local authority planning department will be able to advise on any special requirements, particularly relating to the necessary appearance of the finished works. There are a range of finishes which can be used to emulate the surrounding properties and samples can be provided to satisfy local authorities.
Also, if you live in a terrace house and your external wall abuts directly on to a public pavement then the extra depth to your wall may be viewed as an encroachment onto public space and so you may need to apply for planning permission. Generally, EWI is not classed as an extension to the walls as the depth is only being increased by inches. However, this does mean a degree of alteration to exterior fittings and fixtures and as such a Building Notice is required. We will complete this on your behalf and is part of our service to you.
Further information on planning permission can be found on the Planning Portal website at www.planningportal.gov.uk. Part of our service can be to complete planning applications, including drawings (elevations), technical information and other application needs. This cost of the planning application will be reflected in your estimate, liaising with the planning officers are part of our service to you.
How do I choose between the different types of finish? Once completed, EWI can either have the same look as existing render or brick on your home or can transform the appearance of a property. The finish is a personal choice taking into account the desired texture and colour. Changes to the final appearance of the property may require planning permission. There are a number of different products, textures and coloured finishes to choose from and vary by manufacturer. These include mineral renders which can be finished with dry dash aggregate or the final surface can be scraped back to leave a textured finish, synthetic finishes come in silicone, acrylic or silicate plasters in a variety of colours and textures or brick slips or brick effect render offers a traditional finish. We can show you samples of each finish and various colours.
How much does EWI cost? It is difficult to provide an estimated cost for professional EWI installation due to variations in the construction and condition of buildings as well as the insulation, manufacturer and finish chosen by the owner. The final cost will be influenced by a number of factors including:
Insulation thickness and type (manufacturer)
Finish (brick effect or brick slip is on average more costly than stock render colours)
Size of the wall area
Number of windows and doors
Number of flues/vents to install or extend.
Condition of the exterior surface and any building works necessary to prepare the walls for EWI
If there are any utilities that need to be temporarily relocated or gas lines to be extended.
Ease of installation access and any scaffolding requirements.
Planning applications and requirements.
Do I have to pay VAT on EWI work? VAT is payable on repair, maintenance and improvement works. A reduced rate of VAT (currently 5%) is applicable to any professional EWI installation, provided that its primary purpose is to save energy.
What are the Benefits of installing EWI?
EWI creates a thermal barrier around your walls and prevents far less cold penetrating into your home and less heat loss to the outside. Your home will be comfortable in cold conditions and cooler in warmer conditions too.
Reduce your fuel bill. High insulation levels achieved by the installation of an External Wall Insulation system result in savings on energy bills. An average solid wall semi-detached home could save around 45% per year on fuel costs (Source: Energy Savings Trust).
EWI helps protect your external walls from the effects of the weather, helping your home last longer and improve/update the appearance of your home. Wind, rain, frozen conditions and the occasional heat wave mean that your walls eventually need repair with costly re-pointing, re-rendering or special treatments to prevent them from deteriorating. A multi-layered protective render finish will ensure that your external walls are shielded from the elements and save on expensive maintenance measures in the future. Additionally, if your home is currently not a great sight to see, EWI is a great option for updating the look as well as the energy efficiency and doing your part to help the environment by reducing the carbon footprint of your home. *http://www.confusedaboutenergy.co.uk
Solid wall properties can experience damp problems. External walls can become porous and allow penetrating damp into the home. Cracks and gaps can form over time which allow damp along with draughts into your property. Internal condensation is common too because cold walls can attract moisture. All of these potential problems can be costly with internal damage to your decor and if left untreated can result in mould which can be hard to get rid of. Installing EWI will provide your home with a new weatherproof layer which will help to protect against penetrating damp and fill any minor cracks and gaps for years to come. Your walls will remain warm to touch and will be far less likely to suffer from condensation in the future all of which will mean that your internal decor will last longer and need less frequent maintenance.
EWI is excellent at reducing external noise levels and will make your home more peaceful if you live in a noisy location.
EWI will Increase the value your of home, homeowners who install energy efficient products will add thousands of pounds of value to their properties as fuel prices continue to increase in the future.
EWI render systems in summary: • Are a cost effective alternative to demolition & rebuild • Reduce unnecessary heat loss & CO² emissions • Reduce heating bills. • Reduce condensation on the inside of the property and help to reduce damp. • Protect and prolong the external fabric of a building • Offer superb weather resistance • Low maintenance • Do not reduce footprint of a property • Have a positive effect on the environment • Provide an aesthetically pleasing decorative finish to the property. • Increase value to the property.