Low-Rise Housing
Permarock systems are designed to provide thermal and aesthetic improvements to all forms of low-rise housing.
However, they are especially well suited for the improvement of ‘hard to treat’ properties, such as solid wall and non-traditional buildings, and those for which cavity wall insulation is not suitable. Consequently, they are ideal for use on decarbonisation schemes and retrofit projects involving low-rise social housing.
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 system will provide a number of important benefits:
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Lower fuel bills: heat energy losses through the external walls are dramatically reduced. High levels of energy efficiency can be achieved over other forms of insulation, resulting in savings on energy bills.
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Weather protection: a Permarock system protects the building fabric from the worst excesses of the weather and allows damp structures to dry out. As a result, a longer useful lifetime can be expected from the building.
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Durability: Permarock systems are approved for use in all locations in the UK including those considered to have ‘very severe exposure’ (Level 4) for wind-driven rain. They have successfully been used in very severely exposed coastal sites.
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Healthier conditions: an external wall insulation system, when detailed correctly, can overcome the effects of cold bridging, thereby eliminating condensation and dampness.
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Interior comfort: with an EWI system installed, 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.
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Improved appearance: our systems are durable and cost-effective, and can improve the appearance of older buildings.
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Greater convenience: EWI systems are applied externally, so the installation can take place without disruption to the occupants. For the same reason, there is no reduction in interior living or working space.
- Technical support to make clients’ budgets achieve more
Supporting Decarbonisation Schemes
Permarock has extensive experience of working with stakeholder partners on publicly-funded retrofit projects delivered in accordance with the latest PAS standards. Our products have been installed by accredited installers on social housing decarbonisation schemes across Britain.
PAS2030/35 Compliant Guarantees
Permarock external wall insulation systems are suitable for use on publicly-funded schemes such as: Warm Homes: Social Housing Fund (WH:SHF)
They are certificated through the Kiwa Agrément to ensure compliance with UK Building Regulations. This includes use on high-rise buildings. They meet the requirements of PAS 2030 / PAS 2035 for use under energy efficiency initiatives supported by utility companies and UK Government.
About the PAS Standards
PAS 2030 and PAS 2035 are Publicly Available Specifications that relate to the installation of energy efficiency measures in existing domestic buildings. Issued by the British Standards Institution, they promote a whole-house, fabric-first approach to decarbonisation. Schemes that draw upon public funding must be delivered to these standards.
PAS 2035 was introduced at the behest of the Department for Business, Energy and Industrial Strategy, which sought a structured framework for allocating energy efficiency retrofit funding. PAS 2035 prioritises measures that will have the greatest positive impact in terms of energy savings and other benefits for residents. To ensure this, projects must be supported by various retrofit role-providers: assessors, coordinators, designers and installers. As a system designer, we are experienced in working closely with all such roles.
View the PAS 2035 standard document.
PAS 20230 is a certification scheme with which installers must comply in order to be able to claim funding. One of the requirements of PAS-compliant schemes is that they must be delivered by Trustmark-registered installers. Where required, we will be happy to refer clients to Trustmark-registered contractors from within our network of Registered Installers.
The Latest Standards
Following a public consultation, BSI published the updated PAS 2035/2030:2023 standards in September 2023. These replace the previous (2019) standards, which were withdrawn in March 2025.
Meeting the Standards
To support clients in meeting the latest PAS standards, Permarock will:
- Work closely with the Retrofit Designer and the Retrofit Installer.
- Use property-by-property survey data to provide a full set of specifications, details and calculations.
- Produce site-specific supporting data for wind loadings, fixing requirements and condensation analysis.
- Work with the Retrofit Designer to ensure all cold bridging risks are dealt with in accordance with the external wall insulation specification for ‘Weathering and Thermal Bridge Control – Guide. May 2019,’ which is referenced in PAS2035/2030+A1.
- Ensure that the system (and all detailed interfaces with other parts of the dwelling or other planned Energy Efficiency Measures) deliver optimal performance. Junctions (e.g. between the EWI system and replacement windows, soffits, vents etc.) will be safe, durable and fully weatherproof for all expected exposure conditions.
- Pay particular attention to the efficacy and durability of the detailing, especially with respect to the risks of water penetration and surface/interstitial condensation.
It is important that specifications for external wall insulation systems are PAS-compliant. If they are not properly detailed or specified, key elements may be omitted from contractors’ pricing. This can result in variations once the project goes to site. Alternatively, if the system is installed and found not to be compliant, any associated public funding may be withdrawn.
We are highly experienced in supplying systems that are PAS-compliant. By assisting social housing providers, specifiers and contractors in the specification, detailing and installation of their external wall insulation systems, we help to ensure both compliance and greater certainty on costs.
Low-Rise Housing
The installation of a Permarock external wall insulation system to a solid wall or non-traditional property can stabilise the structure by reducing thermal movements whilst also protecting the building fabric from water ingress and weathering. This can extend the useful life of the property.
Our systems also enhance the comfort of the building’s occupants by eliminating cold bridging, and by minimising the risks of dampness, condensation and mould-growth.
U-Values & Solid Wall Properties
The following table indicates the insulation thickness required to achieve a range of U-values for 229 mm solid brick construction:
We can carry out U-value calculations and condensation risk analyses for any specific wall construction. Please contact our technical department for further information.
Non-Traditional Housing
We offer solutions for many prefabricated reinforced concrete (PRC) house types, as well as for other non-traditional or system-built types, including:
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, in cold conditions, help to raise the temperature of the building fabric. This helps to eliminate interstitial condensation, reducing dampness, and allowing the property to dry out. Reducing the moisture content of concrete reduces the risks of reinforcement corrosion and can therefore prolong the life of the structure – a particularly important benefit for PRC buildings.
System specification and detailing can be extremely important on Non-Traditional property types. Our systems have been installed to most types of construction over the past 40+ years, so we 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 if they are to accept the EWI system load.)
Find out More
For further information about specifying systems for social housing properties, please call our technical support team on 01509 262924.
