Lightweight pre-fabricated elements are applied on the facade walls of a building for decorative purposes. Cornices, floor markers, window frames and modillion brackets are made according to specific designs using polystyrene foam coated with weather resistant materials that provide a plaster effect.

The light weight of the polystyrene foam makes installation quick and easy even in the most diffi cult situations. The coating materials in concrete-and-resinbased plaster provide a perfectly weather resistant layer.

Arbloc supplies the shock resistance data needed to establish the level of resistance to hailstones or other forms of accidental shocks/impact for each type of material. Arbloc offers two types of pre-fabricated elements: Series 2004, Series 2006.

Technical data

Users must know the features of a lightweight pre-fabricated element in order to install it properly.

Thermal expansion

The thermal expansion of polystyrene foam is higher than stone-like materials usually used in construction. The λ coefficient ranges from 5 · 10-5 – 7 · 10-5. Compared to concrete (λ = 1.2 · 10-5), polystyrene’s thermal expansion is 4 to 6 times higher. Variations can reach 1.5 mm per 1 m in length with a 30°C thermal increase.
Hence each installation must be evaluated carefully, especially in terms of support, glues, and mechanical anchors, besides the finish of the joints.


Lightweight prefabricated elements are fixed on different kinds of supports. Considering that cement, bricks, insulating materials, plaster, and wood all have different thermal expansions, the fixing method must be evaluated and chosen according to the characteristics of the support. For example, some kinds of plaster are friable and therefore easily susceptible to polystyrene thermal expansion.

Shock resistance

Lightweight pre-fabricated elements have been tested for any accidental impact that could damage them. Different coating materials provide more or less resistance.


Hailstone can damage the coating of our lightweight prefabricated elements. he following table shows the force in joule calculated by relating the diameter of the hailstone and its fall speed, according to the formula E = m – V2 – 0.5