Polystyrene is made by polymerizing styrene which is produced by combining benzene and ethylene. The polystyrene thus produced is one of the thermoplastic materials sometimes called linear polymers. These are materials which soften on the application of heat and harden as they cool.

The expanded foam (known as EPS) is produced as small beads containing a blowing agent which is expanded by treatment with steam to form pre-foam of the required density. The pre-foam is then fed into moulds and more heat (steam) is applied. This heat fuses the beads together to produce items in a variety of shapes and sizes, or to make blocks for cutting into sheets and other products.

EPS contains no CFC’s and is considered ozone-friendly by the Wildlife Society of South Africa.


  • Resistant to vibration
  • Low mass
  • Thermally efficient
  • Recyclable
  • CFC free, physiologically and chemically harmless
  • Resistant to aging, mildew, bacteria and rot
  • Easily cut and worked (fine toothed saw and conventional hand tools)
  • Easily bonded ensure adhesive is compatible with EPS
  • Easily painted using high quality acrylic PVA applied by brush or spray
  • Flame retardant EPS distinctly reduces the flammability and the spread of flame on the surface of foamed articles. This product is self-extinguishing as soon as the ignition source is removed
  • Fire Retardant FR grade (Styrene unfaced) has obtained a B/B1/2/H&V with & without sprinklers when tested in accordance with SANS 428

Refer to physical properties table.

  • Odorless, inert and fully compatible with all standard building materials & components
  • Resistant to fresh water, salt water, alcohol, weak & certain strong acids, weak & strong alkalis, resistant to most vegetable and animal oils
  • EPS is vulnerable to ketones, esters, hydrocarbon chlorides, benzol, petrol, fuel & turpentine ether
  • Will not promote corrosion of steel, copper or aluminium
  • Will not sustain vermin
  • Will not breed or promote fungi, mould or bacteria
  • Rot proof

EPS is not known as a good sound absorbing product due
to its closed cell structure and low density. Insulpro offers
a range of alternative acoustical insulation products if


Cost competitive insulation material with application
in a wide range of industries. Excellent thermal
properties, lightweight and other user friendly features
combine to provide almost infinite product potential.

  • CFC free
  • Recyclable
  • Does not decompose into harmful substances
Properties 16D 24D 32D
Density (kg/m) – tolerance +/- 10% 15 24 30
Thermal conductivity at 10C (w/mk) (mean temperature) 0.036 0.033 0.032
Compressive strength (kpa) – @ 10% deformation 85 170 225
Tensile strength (kpa) 200 310 440
Water absorption (%) 0.5 – 1.5 0.5 – 1.5 0.5 – 1.5
Temperature limits -150C to 80C