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External Insulated Walls

What are External Insulated Walls?

An External Insulated Wall (also known as 'Super Insulated Masonry (SIM) Walls' consists of a solid aerated block with a layer of high performing insulation fixed externally to the masonry wall with a choice of finishes.

This system enables the building designer to reduce thermal bridging, increase air tightness, and reduce costs. Further enhanced design details to the floors and roof can then increase the u-value performance of the whole of the building.

The Solid Masonry Core:

A super lightweight aerated block with a thermal value of just 0.09 W/mK. Furthermore, the benefits of the Thermal Mass effect of masonry walls is maximised as the insulation is on the outside.

The External Insulation:

An external surface of Neopor is then fixed to the block. Neopor is a unique insulating material using much less energy in its manufacture and is 20% more effective than similar materials.

External Finishes:

There is an extensive choice of finishes for the external wall, including high performance renders in various textures and colours. A wide range of brick slips, conventional brickwork or stone can be used.


  • U-Values below 0.10 W/mK are achievable using only 2 main layers plus finishes
  • A fast, proven, flexible, effective and repeatable build technique
  • Up to 15% lower in build costs than framed equivalent constructions
  • A+ green guide rating
  • Zero thermal bridging
  • Zero condensation risk
  • Maximises the thermal mass of the build meaning less seasonal temperature fluctuation throughout the year
  • Future-proof, robust and resilient build, which is easily modified when required
  • Thin Joint Masonry

    A mortar joint of 2mm provides a stronger bond than conventional mortar joints. The thin joint mortar is quick setting, gaining strength within 20 minutes, allowing walls to be built continuously without height restrictions.


    The reduced area of the thin joint further improves the u-value of the wall and restricts air leakage. Air leakage tests on site show that 0.6 m³/hr/m² is readily achieved.

  • Recommendations for External Insulated Walls

    To complement the high-performance wall, it is necessary to consider the other elements within the construction in order to achieve low energy, low carbon sustainable homes.

    • Floors and roof to be designed to a high specification, where 0.11 W/m²K is easily achievable.
    • Detailed attention to the junction of the dwelling to avoid cold bridging can offer figures typically Y = 0.02.
    • By adopting these designs, a construction can be built to future low carbon, low energy requirements without the need for additional renewable energy components.
  • Economic Benefits

    • low energy, low carbon homes are achievable without the need for expensive renewable energy technology.
    • Low maintenance costs – no expensive solar panels, damage to walls and reduced energy costs.
    • Lower build costs – up to 15% on framed buildings with same build time.
    • Quicker lead times, no bulk purchases required for servicing site.
  • Environmental Benefits

    • The fabric used in the construction is at the core of our ethos that the materials used should show ecological and sustainable benefits and most importantly provide the dwelling with a long service life with low maintenance.
    • We offer full technical support on design and construction, training and supervision of site staff to ensure that the project is designed and built to the clients’ satisfaction.
    • It is our desire to see the UK build low energy use homes following the principles of PassivHaus in design construction to the highest standards with reductions in energy usage and costly renewable energy sources.