Low / Zero Carbon Buildings

Working closely with building designers, PermaRock can advise from design stage through to installation on how the external wall insulation element of a project can meet low carbon design requirements and contribute to or exceed Passivhaus, BREEAM, Code for Sustainable Homes (Levels 4-6) and similar performance standards.

Through the use of a PermaRock external wall insulation system, heating demand can be dramatically reduced, conserving energy and reducing CO2 emissions and very airtight façades can be created - important factors in the
design of energy efficient buildings.

Although external walls are an extremely important contributing factor, a number of other important considerations can impact on the design process of low carbon and sustainable buildings; including building orientation, window and door type and placement, overhang depth, the efficiency of heating, cooling, lighting equipment, occupant behaviour, not to mention the local climate.



The Passivhaus standards’ strength lies in the simplicity of its approach; construct a building that has an excellent thermal performance, exceptional airtightness and mechanical ventilation. The standard can be applied to residential, commercial, industrial and public buildings. 

Passivhaus buildings achieve a 75% reduction in space heating requirements compared to standard practice for a UK new build. The Passivhaus standard therefore gives a robust method to help the industry achieve the 80% carbon reductions that are set as a legislative target for the UK Government. Passivhaus buildings readily achieve Code for Sustainable Homes level 4 without the need to incorporate micro-generation.

The core focus of Passivhaus design is to dramatically reduce the requirement for space heating and cooling. This can be achieved without compromising comfort or needing to rely on the falling costs of renewable energy technologies. 

The Passivhaus Standard requires: 

  • A maximum space heating and cooling demand of less than 15 kWh/m² year or a maximum heating and cooling load of 10W/m².

  • A maximum total primary energy demand of 120 kWh/m²/year.

  • An air change rate of no more than 0.6 air changes per hour @ 50 Pa.

Achieving the Passivhaus Standard in the UK typically involves:

  • Very high levels of insulation.
  • Extremely high performance windows with insulated frames.
  • Airtight building fabric.
  • ‘Thermal bridge free’ construction.
  • A mechanical ventilation system with highly efficient heat recovery.

PermaRock has been involved with a number of Passivhaus projects that have achieved full Passivhaus Certification, including Oakmeadow & Bushbury Hill Primary Schools, Wolverhampton (two of the first certified Passivhaus schools in the UK) the Centre for Disability Studies in Essex (one of the first non-domestic buildings to achieve Passivhaus certification in the UK) and Mayville Community Centre, Islington

PermaRock’s systems help contribute towards high thermal performance levels, thermal bridge free construction and airtight building fabric that are required. Our technical services are typically consulted and engaged during the early stages of the building design process to assist in the detailing and specification of the PermaRock external wall insulation system.


BREEAM (the BRE Environmental Assessment Method) is the most widely used environmental assessment method for buildings in the UK. The assessment addresses a wide range of environmental and sustainability issues and sets the standard for best practice in sustainable design. This enables developers and designers to demonstrate the environmental credentials of their buildings through a recognised measure of environmental performance. Buildings are then rated with either a Pass, Good, Very Good, Excellent, or, for exemplar buildings, an Outstanding rating. The assessment commences at design stage and is then verified post construction when the final certificate is issued.

In order to meet or exceed BREEAM requirements, PermaRock can design external wall insulation systems that are extremely high in terms of thermal performance and that can create ‘thermal bridge-free’ junctions between walls, floors, roofs and produce very airtight building envelopes. 

Code for Sustainable Homes (CSH)

The Code for Sustainable Homes is a guide to how a development should perform against a number of specific criteria. It aims to reduce carbon emissions and promote higher standards of sustainable design above the current minimum standards set out by the building regulations.

The Code measures the sustainability of a new home against categories of sustainable design, rating the ‘whole home’ as a complete package. The CSH sets out 6 levels, with level 1 being the least sustainable and level 6 being the most sustainable. Before it was redefined, Zero Carbon was associated with CSH level 6.

The Code sets minimum standards for energy and water use at each level, within England and Wales, and will be closely linked with the future direction of Building Regulations in relation to carbon emissions and energy use in homes.

PermaRock external wall insulation systems can incorporate high levels of insulation to contribute significantly to reducing heat losses/gains, thereby reducing heating and cooling demands, thus reducing energy and CO2 emissions – one of the six mandatory performance requirements.

PermaRock systems can achieve U-values of 0.10 W/m²K and below and can be designed to eliminate thermal bridges – another important factor at higher levels of the Code for Sustainable Homes.

Green Guide to Specification

Specifiers working on sustainable developments require information on the environmental impact and performance of building components and assemblies so that they can assess their buildings against the Code for Sustainable Homes. The BRE’s Green Guide to specification provides a rating system for thousands of typical construction components and assemblies which designers and specifiers can refer to when making environmental choices in their selection of materials. 

The environmental ratings, described in the Green Guide, are based on life cycle assessments (LCAs) which take into account the winning of raw materials, manufacture, transport, assembly, maintenance, repair and replacement, demolition and waste management at the end of life. The Green Guide does not take into account operational performance in terms of potential energy savings of materials or systems with high insulation values or thermal mass.

PermaRocks systems achieve excellent LCA scores which will translate into Green Guide ratings of A/A+. 

PermaRock’s systems help contribute towards high thermal performance levels, thermal bridge free construction and sn airtight building fabric.

Also In This Section

Sustainable Products

PermaRock systems provide an excellent opportunity to reduce carbon emissions in buildings, however, we also realise the important part we play in protecting our environment, which is why we try to minimise our carbon footprint wherever possible...
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