External Wall Insulation – Mechanical Fix

S and B External Walls

S and B EPS - external wall insulation system

Product Information

Around 35% of the energy used to heat and cool a building 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 an external facade system 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, 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 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