Technical Information

Materials

XPS

Extruded Polystyrene Foam

Extruded polystyrene foam (XPS) consists of closed cells, offers improved surface roughness and higher stiffness and reduced thermal conductivity. The density range is about 28–45 kg/m3.
Because of the extrusion manufacturing process, XPS does not require facers to maintain its thermal or physical property performance. Thermal resistivity is usually about 35 m·K/W (or R-5 per inch in American customary units) but can range between 29 and 39 m·K/W depending on bearing/density. Thermal conductivity varies between 0.029 and 0.039 W/(m·K) depending on bearing strength/density and the average value is ~0.035 W/(m·K).

Water vapour diffusion resistance (μ) of XPS is around 80-250 and so makes it more suitable to wetter environments than EPS.

Extruded Polystyrene (XPS) is manufactured to TIASA standards with fire classification in accordance with SANS 428.

EPS

Expanded Polystyrene

Expanded polystyrene (EPS) is a rigid and tough, closed-cell foam. It is usually white and made of pre-expanded polystyrene beads. Thermal resistivity is usually about 36 m·K/W but can range between 34 and 38 m·K/W depending on bearing/density. Thermal conductivity varies between 0.034 and 0.038 W/(m·K) depending on bearing strength/density and the average value is ~0.036 W/(m·K).

Water vapour diffusion resistance (μ) of EPS is around 30-70.

Some EPS boards have a flame spread of less than 25 and a smoke-developed index of less than 450, which means they can be used without a fire barrier (but require a 15-minute thermal barrier) according to US building codes. A growing use of EPS in construction is insulating concrete forms. The density range is about 16–640 kg/m3.[6] The most common processing method is thermal cutting with hot wires.

Expanded Polystyrene (EPS) material is manufactured to EPSASA (member of TIASA, administered by AAAMSA) standards and spesifications.

Safety

Fire Resistance

Expanded Polystyrene (EPS) material are manufactured to EPSASA (member of TIASA, administered by AAAMSA) standards and spesifications. All the cornice material contains Fire Retardant additive and are manufactured without the use of CFC/HCFC. The tests are done under the SANS 10177 and SANS 428 standards.

Extruded Polystyrene (XPS) is manufactured to TIASA standards with fire classification in accordance with SANS 428.

General

Glue

We supply and recommend DEVCHEM CORNICE ADHESIVE which is available in 5l tubs and 260ml tubes/cartridges.

DEVCHEM CORNICE ADHESIVE is an white, high strength, flexible, low shrinkage ready mix paste adhesive used to bond cornices including polystyrene cornices to a variety of different substrates such as plaster, painted or cement surfaces.

DEVCHEM CORNICE ADHESIVE can be painted over with any suitable paint such as PVA, Acrylic or Enamel.

Uses / Applications:

  • Good initial grab
  • Can be painted over
  • Low shrinkage
  • Good flexibility
  • Strong adhesion to a variety of substrates
  • Ready mix paste – easy to use
  • Bonds light weight tiles to various substrates

Other Information:

  • Do not use at temperatures below 5 degrees celcius
  • Protect from freezing
  • Do not apply to wet or very damp surfaces
  • As with any water based adhesive at least one of the surface should be porous to allow moisture in the adhesive to escape

Paint

Use only Acrylic or PVA based paints. There is no need for an undercoat or preparation of the polystyrene before or after installation.

Avoid contact with enamel, solvent-base paints and plaster primer.