Solid Wall & Non-Traditional Properties

PermaRock systems are designed to provide thermal and aesthetic improvements to all forms of construction types but are especially suited for application onto ‘Hard To Treat’ properties, such as Solid Wall and Non-Traditional buildings, or where cavity wall insulation is not suitable.

With up to 35% of heat lost through the walls on ‘hard to treat’ and solid wall properties, the application of a PermaRock external wall insulation (EWI) system will provide a number of positive benefits to the building and its occupants:

  • Lower fuel bills: Heat energy losses through the external walls are dramatically reduced and high levels of energy efficiency can be achieved over other forms of insulation resulting in savings on energy bills.
  • A PermaRock system protects the building fabric from the worst excesses of the weather and allows damp structures to dry out. As a result, the building can expect a longer useful lifetime. 
  • An external wall insulation system when detailed correctly can overcome the effects of cold bridging, thereby eliminating condensation and dampness.
  • The original wall construction can be used as a heat store. This thermal mass helps to reduce temperature fluctuations and maintains a more comfortable internal environment. 
  • Systems are durable, cost-effective, and can improve the appearance of older buildings. 
  • Application can take place without disruption to the occupants and there is no reduction in interior living or working space.

PermaRock systems are approved for use in all locations in the UK including those considered to be ‘very severe exposure’ (Level 4) for wind-driven rain and have been used in environments including severe and very severely exposed coastal sites.

Low-Rise Housing

Installation of a PermaRock external wall insulation (EWI) system to a solid wall or non-traditional property can stabilise the structure by reducing thermal movements whilst protecting the building fabric from water and weathering.

This can extend the useful life of the property whilst enhancing comfort levels by eliminating cold bridging, dampness, and condensation. Aesthetically, existing buildings can be brought back to life with one, or a combination of PermaRock’s decorative renders or finishes.

The following table indicates the insulation thickness required to achieve a range of U-values for 229 mm solid brick construction:


Indicative U-value Requirements

(229mm Brick Solid Brick Construction)

Insulation Thickness (mm) Required

U-value (W/m²K) Mineral Fibre EWI
EPS-Premium EWI
EPS EWI System PIR EWI System
0.30 100 90 110 70
0.28 110 100 110 80
0.25 120 110 130 90
0.20 160 140 170 110
0.15 210 190 230 -


U-value and condensation risk analyses for any specific wall construction can be compiled – please contact our technical department for further information.

Non-Traditional Housing

PermaRock is able to offer solutions for many PRC house types, as well as for other non-traditional or system-built types, including the following:

Airey / BISF / Bison / Cornish / Dorran / Easiform / Hawthorne-Leslie / Hawksley BL8 / Orlit / Reema / Swedish Timber Frame / Tarran / Trusteel / Unity / Vic Hallam (various) / Wates / Wimpey No-Fines / Woolaway

The application of an EWI system will raise the temperature of the building fabric, eliminating interstitial condensation, reducing dampness, and allowing drying out to occur. Reduction in the moisture content of concrete reduces reinforcement corrosion and can therefore prolong the life of the structure – a particularly important benefit for PRC (prefabricated reinforced concrete) buildings. 

System specification and detailing can be extremely important on Non-Traditional property types – PermaRock has completed installations to most types of construction during the past 30 years and can advise on the best solution for your specific scheme. Please note that a structural survey may be required as properties must be structurally sound to accept the EWI system load.

Also In This Section

Colour & Sample Selector

Use our innovative and easy-to-use colour and sample selector to view, choose and finalise your colour selections. You can view our entire range of decorative renders and finishes and ordering samples couldn't be easier.

Why PermaRock External Wall Insulation?

PermaRock systems have been designed for use on high and low rise buildings, for traditional and non-traditional forms of construction, including, solid wall or cavity wall, dense and no-fines concrete, brick, stone and metal,...
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