The external wall insulation industry is full of abbreviations and terminology that seemingly make very little sense unless you have the knowledge of the topic.

Here we give you insight into some of these terms and acronyms that you’ll find across the construction industry and help you understand and grasp them so you can discuss the industry specifics confidently on site. 


The Building Research Establishment Environmental Assessment Methodology is the world’s leading sustainability assessment method for master-planning projects, infrastructure and buildings. The BREEAM assessment process evaluates the design and construction of a development against targets that are based on performance benchmarks.

The assessments are carried out by independent, licensed assessors and developments are rated and certified on a scale of Pass, Good, Very Good, Excellent and Outstanding. Take a look at our Junction 3 Case Study which achieved a BREEAM Very Good rating. 


BIM is an acronym for Building Information Modelling, it is a digital representation of a building’s design process and materials. SPSenvirowall external wall insulation systems are available as BIM objects via the NBS National BIM Library and are IFC and Revit compatible. 

Visit the National BIM Library to download these files


An Energy Performance Rating, is a guide that tells you exactly how energy efficient a building is and provides an energy rating from A (very energy efficient) all the way down to a G (least energy efficient). An EPC assessment will tell you the energy efficiency such as wall, roof and floor insulation, efficiency of the boiler, the lighting efficiency and whether or not the property has single glazed or double glazed windows. 


An acronym for expanded polystyrene insulation, EPS is a lightweight, easy to cut, easy to install thermal rigid foam. 


An obvious one, External Wall Insulation, also referred to as SWI – Solid Wall Insulation, is a system consisting of high performance insulation which is fitted to the exterior walls of a building which insulates and protects the exterior.

The system is then covered with render cladding which can vary in colour and textures.

Get more information about our external wall insulation systems on our Products page where you’ll find everything you'll need from fixings to finishes. 

Lambda Value (W/mK)

Expressed as Watts per metre Kelvin, the heat conductivity of material is known as its lambda value. A slower conduction of heat means a lower lambda value. 


NHBC is the UK’s leading independent standard-setting body and provider of warranty and insurance for new homes. They work with the house-building industry to raise the standards of new homes and to provide protection for homebuyers in the form of Buildmark warranty and insurance. All of SPSenvirowall products have NHBC approval. Check out our case study about Kaleidoscope, a modern development which required full NHBC compliance.

R-value (m2K/W)

Put simply, an R-value is a measure of resistance to heat flow through a given thickness of material (such as insulation). The measure of how well a material insulates at its given thickness is shown as m2 Kelvin per Watt, so the higher the R-value the better. 

U-value (W/M2K)

A u-value (also known as thermal transmittance) measures how effective an insulation material is. It calculates the rate of transfer of heat through a structure, divided by the difference in temperature across that structure. The better-insulated a structure is, lower the calculation will be and is expressed in Watt per m2 Kelvin. If you need help with a U-Value Calculation, you can contact our Technical Team for help via our Contact Page.


An acronym for Polysocyanurate, PIR is a thermoset plastic produced as a rigid foam used to make high performance insulation materials.