External Wall Insulation – Mechanical Fix

S and B External Walls

S and B EPS - external wall insulation system

Product Information

Over a third of the energy used to keep a building at ambient temperature is lost via its external walls. External wall insulation (also known as Solid Wall Insulation) is one of the quickest and most effective ways to improve energy efficiency; whilst at the same time transforming a building’s external aesthetics.


Expanded polystyrene boards are perfect for use in external facade systems and help to provide an efficient and cost-effective energy-saving solution. S and B EPS external wall insulation is an accepted and affordable way of reducing unnecessary energy loss. It does this by adding thermal value to the outer face of external walls.


In many new-build applications, S and B solid wall insulation is applied to a building’s external framework (brick, block, timber or steel frame)  by way of a supportive rail system. This supportive framework not only creates a natural drainage cavity to aid moisture egress but also helps towards creating a denser thermal barrier.


Similarly, an external wall rail system can also be used on dwellings such as non-traditional houses, or properties with a brittle substrate, especially where the insertion of mechanical fixings would prove detrimental to the fabric of the building.


The versatility of EPS allows it to be used with a variety of finishes including weatherboarding, cladding, tile hanging and reinforced render systems.


S and B offer various bespoke grades for thermal wall insulation; grades such as S and B External Wall Insulation, S and B Lambdatherm® (a graphite enhanced, low thermal valued board), plus EPS 70E and EPS 200E – all containing a polymeric fire retardant additive. Thermal values range depending on product and thickness from 0.038 down to 0.030 W/mk. Selected grades of EPS raw material are used for external wall applications to reduce any bowing and shrinkage of the EPS.


Recent years have seen a huge growth in the use of solid wall insulation on domestic properties, especially following government-funded initiatives such as the Green Deal and the Green Homes Grant.

Rail System Boards:

S and B Rail System Insulation Boards come in a standard dimension of 500 x 500mm, ranging from 40mm up to 250mm in height. These boards are recessed and rebated on all four sides to aid fitting to a rail system that has been mechanically fixed to an external wall.


Expanded Polystyrene (EPS) is 100% recyclable. Any leftover waste can be disposed of via our ‘Waste Recycling Scheme’.  Ask a member of our team for further details.


S and B EPS External Walls are available in:


EPS 100E

EPS 150E

EPS 200E

EPS 250E

Lambdatherm® 70E

Lambdatherm® Elite


  • Our EPS insulation boards are EWI system designer approved.
  • EPS is 98% air and is, therefore, an excellent thermal insulator.
  • The closed-cell structure of expanded polystyrene inhibits water absorption leaving it unaffected by the normal range of climatic conditions.
  • Faster, more efficient single leaf construction can be used, creating additional internal space with improved thermal performance.
  • EPS is lightweight, easy to cut and install.
  • S and B EPS is manufactured right here in the UK.
  • ETAG 004 compliant
  • Green guide A+ rating
  • Expanded polystyrene is 100% recyclable

To discover more about the benefits of S and B, call today on 0191 250 0818 

Technical Information

Features Grades EPS Lambdatherm®

Thermal Conductivity

[k] value W/mk (10.C mean)

0.038 0.036 0.035 0.034 0.033 0.031 0.030

Compress Strength

kPa Min (at 10% compressivew strengths)

70 100 150 200 250 70 100

Cross Breaking Strength

kPa Min

115 150 200 250 350 115 150

Safe Working Load

kPa at 1% nominal compression

21 45 70 90 100 21 45

Vapour Diffusion Resistance

factor µ1

20-40 30-70 30-70 40-100 40-100 20-40 30-70

Vapour Permeability

omg [pa.h.m]

0.015 to 0.030 0.009 to 0.020 0.009 to 0.020 0.006 to 0.015 0.006 to 0.015 0.015 to 0.030 0.009 to 0.020

Colour Guide

Non-Responsive Table
Identification / colour coding of products manufactured to BSEN 13163
EPS 70E 2 x brown stripes & 1 red stripe      
EPS 100E 1 x black strip & 1 red stripe    
EPS 120E 2 x green stripes & 1 red stripe        
EPS 150E 1 x yellow strip & 1 red stripe          
EPS 200E 2 x black stripes & 1 red stripe        
EPS 250E 1 violet stripe & 1 red stripe          
EPS 500E 2 x black stripes & 1 red stripe        

Product Gallery

Youtube S and B
External Wall - Mechanical Fix Video