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Case Study – EPS onto Brick

At EWI Pro, we specify many projects throughout the UK. They vary in size, scope, and system application. From large-scale commercial projects to small-scale residential, we cover every type of project. As we’ve discussed recently, we provide a comprehensive range of testing processes. These include wind-load tests, moisture testing, and pull-out tests. Our Technical Team also provides expert U-value calculations to ensure the system is suitable. In our new series of blogs, we will shine a light on specific projects and the build-ups they utilise. Our next case study is to examine one of our most popular build-ups, EPS onto Brick. The UK housing stock is made up of primarily brick housing, especially houses predating the 1920s. As they stand, they will tend to be without insulation, and therefore, extremely energy-inefficient. This project addresses those issues with an application of an EPS thermal envelope.

Project details

– Substrate: Existing Brickwork
– U-Value change: 2.7W/(m2K) – 0.3W/(m2K)
– Insulation: Expanded Polystyrene (EPS)
– Insulation Thickness: 90mm
– Basecoat: EWI-225 Premium Basecoat
– Topcoat: EWI-075 Silicone Render – 1.5mm grain size
– Colour: 28010 Porcelain
– Location: Twickenham
– Installer: WeInsulate

The build-up – EPS onto Brick

WeInsulate’s retrofit of an existing brickwork residential property provides an example of our most popular system. Brickwork remains a popular form of construction but does not offer much in the way of thermal insulation.

The focus of this retrofit is the utilisation of our most popular products. EWI-225 Premium Basecoat doubles up as the stable adhesive for the application of the insulation boards, and the reinforcing basecoat to receive the render. EPS is a cost-effective and high-performance insulation board that does not sacrifice thermal performance. Following collaboration with the EWI Pro Business Development Team, WeInsulate installed 90mm of EPS insulation in order to achieve a U-value of 0.3W/(m2K).

The 1.5mm grain size Silicone Render in 28010 Porcelain leaves a delicate and shiny façade. Despite the refined appearance, none of the rugged performance is sacrificed. The hydrophobic properties extend beyond the upper layer of the façade. The installers on this particular project also utilised our DPC (damp proof course) range. Extruded polystyrene (XPS) is a waterproof insulation board, which is crucial for preventing rising dampness. The layer under the DPC is often susceptible to plinth staining; a finish of Silicone or Mosaic Render ensures that the plinth is easy to clean with a pressure washer and brush.

Why do you need to insulate under the DPC?

A Damp Proof Course (DPC) is a barrier, usually a layer of waterproof material, integrated into the structure of a building near the ground level. It is designed to prevent moisture from rising up through the walls or floor by capillary action – a phenomenon called rising damp. The damp proof course can be made from materials such as slate, bitumen, plastic or other specially manufactured materials.

Rising damp can cause several problems in buildings, such as the decay of timber, the deterioration of masonry, and health problems for occupants due to increased humidity and possible mould growth. The DPC is an essential part of building construction to keep the interior dry and healthy.

Insulation under the DPC is necessary to prevent heat loss from the building. Heat travels from warmer to cooler places until there is no longer a temperature difference. In winter, this means heat flows directly from all heated living spaces to adjacent unheated attics, garages, basements, and even to the outdoors. It can also travel indirectly through interior ceilings, walls, and floors—wherever there is a difference in temperature.

However, when insulating below the DPC, it’s crucial to make sure that the insulation does not bridge the DPC or come into contact with the ground. If this happens, moisture could potentially be drawn up into the insulation material, reducing its thermal performance and potentially causing other problems such as dampness.

The insulation below the DPC, often called sub-floor insulation, not only keeps the home warm in winter but also reduces heating costs and increases the comfort and livability of the home. Furthermore, it contributes to the reduction of carbon emissions associated with home heating.

Best ways to cut EPS

WeInsulate utilised hand saws to cut the EPS boards on site. However, this is not the most efficient way. We would always recommend EPS hot wire cutters. Cutting EPS can be challenging due to its structure – it can break into tiny pieces, creating a lot of mess, and it’s difficult to achieve precise cuts with traditional cutting tools.

That’s where hot wire cutters come in. These tools use a heated wire to melt through the EPS, resulting in a clean, smooth cut. Here are some benefits of using EPS hot wire cutters:

  1. Clean Cuts: Hot wire cutters make smooth and precise cuts without leaving a mess of small foam particles, unlike traditional cutting tools such as knives or saws.
  2. Versatility: Hot wire cutters are available in various sizes and can be used to make both large cuts and intricate designs. Some even have adjustable temperature settings for different types of foam.
  3. Efficiency: Hot wire cutters are fast and efficient. They can cut through thick pieces of EPS in a single pass, which can save a significant amount of time on larger projects.
  4. Safety: Because they operate at low voltages, hot wire cutters are generally safer than high-speed cutting tools. The risk of accidental injury is much lower.
  5. Easy to Use: Hot wire cutters are relatively simple to use. Once the wire is heated, you simply guide the cutter through the foam at the desired angle and speed. This makes them accessible to users of all skill levels.
  6. Cost-Effective: While there are professional-grade hot wire cutters that can be quite expensive, basic models are relatively affordable. This makes them a cost-effective solution for individuals and businesses that frequently work with EPS.
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