External Wall Insulation System

Many people lack the understanding of what external wall insulation systems are and their benefits. On this page we are going to walk you through from start to finish of a project that commenced on site Monday 28th May 2018.

We will add regular updates on progression. Below you will find information on:

Property Construction Type
The property is an attractive family home with period characteristics. The main area of the house is 9inch single block construction with no cavity insulation. There is a single floor extension to the rear which has celcon block. The property is currently finished with a dated rough cast render.
Single block / single skin construction is notoriously hard to keep heat in. On top of keeping the heat in and cold out, external wall insulation systems help to eliminate condensation, mould and damp when accompanied by controlled ventilation.
Project Aim: Provide an 'as new' external low maintenance finish. Deliver an insulated uValue of 0.26 on this property which is currently 1.96. Finish the project on time and on budget.
House Before External Wall Cladding
Front of Property Before Work Commenced
Rear of Property Showing Existing Extension
Boast Render Delaminated
Existing Brickwork Detailing

External Wall Insulation Problems Solved

  1. Adhesive Coat
  2. Insulation
  3. Cement Free Reinforcement Coat
  4. Reinforcement Mesh
  5. Decorative Low Maintenance Render Finish
    • Gives major aesthetic improvements
    • Renews ageing exterior façades
    • Greatly improves uValue insulation and buildings thermal performance
    • Contributes to elimination of internal problems, such as damp, condensation and mould growth, when accompanied by controlled ventilation.
    • Lowers maintenance costs & heating bills
    • Limits disruption to the fabric of the building
    • Some systems can help strengthen the existing structure
    • Increases life expectancy of buildings
    • Increases the value of the property
    • Can help upgrade the property to a mortgageable standard
    • Avoids internal building works & can be installed during occupancy
    • Does not reduce the size of rooms
    • Larger amounts of insulation can be added externally

For New Build

  • Simplifies construction, particularly when avoiding thermal bridging and achieving air tightness
  • Easily achieves high levels of insulation without increasing the size of the structure
  • Reduces labour and materials used, leading to a good value construction
  • Usually eliminates the need for a vapour barrier, as the dew-point is transferred to outside the structure
What is u value
Keeping things simple. uValue is the measure which shows the effectiveness of a material as an insulator. Lower uValues prove a property is better insulated.
If you have a low rated uValue this will greatly reduce the heating costs for this property. In this instance a target of 0.26 from a current 1.96 Wmk will keep the heat in and the cold out efficiently.

External Wall Insulation Day 1. Preparing property for EWI

Current property consists of single block construction and a rough cast render finish. The uValue is currently 1.96 Wmk, our target when the external wall insulation system is complete will be 0.26 Wmk.
New Windows Already Fitted
Patching Around Windows & Sills
Checking all areas of render are clean, dry and free from any materials which might impair adhesion. Any boast areas of render will have already been fixed by us prior to commencing date.
Scaffolding has been erected and materials delivered to site. Some of the team are now masking windows and other areas to keep them in perfect condition prior to fixing insulation.

Adding External Wall Insulation Boards

These updates are from 31st May - 8th June. During the second week we have added the insulation boards to the property and fixed beading around windows, at base level, wall angles etc.
Base and Angle EWI Beads
Fixings Covered / Sealed
Property is now completely fixed with insulation and ready for the reinforced mesh render and the attractive finish coat that will make this property look almost like a new build.
With external walls loosing as much as 35% of a properties heat. Using thermal imaging we are able to see the property holding heat within. This will reduce heating costs and make internal temperatures more pleasant.

External Wall Insulation Week 2. Reinforced Mesh Render

Insulation Boards covered with Specialist Render with mesh cloth bedded within.
Adhesive coat is factory manufactured and has full accreditation. Mesh-cloth bedded within improves strength for the system and impact resistance.
Low Maintenance High Performance EWI Finish Applied
The external wall insulation mesh reinforced render system is given a few days to cure then the Sto high performance render finish is applied directly on top. This finish repels water and is through coloured.
By applying EWI angle beads around window in week 2 you can see from this image how neat and straight lines we are able to achieve around detailed areas such as windows.
The texture finish is a fine 1.5mm. When rain water hits it simply runs off due to the factory formulated material. You also get peace of mind with a 10 year guarantee.
With the finish being through coloured, maintenance is considerably reduced. Unlike a painted finish, if the render becomes dirty over a period of time you simply need to wash with warm soapy water and rinse (do not power wash).
The property is now highly insulated and the attractive finish has taken the property to a modern standard.
As external wall insulation approved installers for Sto and all the popular manufacturers. If you are an Architect, Private Individual or Contractor and think EWI is right for you, we would be delighted to quote for your project, or give advice. Click the Enquire Now button below for a quote.