Construction industry

BUILDING MATERIALS

The first signs of the use of lime in constructions date back to 2000 B.C., in southern Galilee, from the Egyptians to Romans and Phoenicians until the Chinese, that used it for building the Great Wall of China.

Calcium hydroxide, or hydrated lime, is a building material obtained by mixing calcium oxide with water in technologically advanced plants. Hydrated lime, mixed with calcareous materials, like sands of various granulometries, or pozzolana - a type of sand rich of silica - or finely ground tuff, with the addition of water produces mortars and plasters for buildings’ interiors and exteriors.

ITALCALCE’s products confer naturalness, healthiness and breathability to the walls of

residential buildings, schools and offices, places in which it is essential to live in a breathable environment.

These products, in addition to allow the perfect evaporation and permeability to vapour in order to avoid the formation of moulds and condensates, respond to temperature differences and lead to an extraordinary result: durability.

• Finely ground calcium oxide is also used in construction, even if indirectly, as basic product for the production of calcium-silicate bricks and calcium-sandy bricks, which are masonry blocks of various thicknesses and low specific weight.

Lime putty is a paste of pure white colour, produced after diluting pure calcium oxide with plenty of water. It is left to settle in tanks/silos for 12 months and then, mixed with extremely fine calcareous sands without chemical additives, it is used for coating interiors or any type of plaster; it is a plastic and breathable finish, it is ecological and extremely resistant to moulds and bacteria. Its use is also valuable in producing paints, venetian stuccos and spatolated, architectural colours and high quality finishes.

The plaster for exterior and interior use is composed of three layers: rendering coat, puckered coat and outer or civil coat; it is prepared in dry form, mixing quarry or marble sand with one or more binders, then lime and cement in the right proportions, finally adding water so as to obtain a sufficiently firm mixture.

The first layer, the rendering coat, has a thickness of 15 -20mm using coarse sand; it is applied in place with a trowel, creating a homogeneous and rough surface. The puckering coat is made to a thickness of 10 - 12mm using medium-grain sand, waiting until the first coat is sufficiently dry.

Finally, the outer or civil coat, with a thickness of 3 - 5mm using fine sand, is the finishing layer of the plaster. The use of lime in the plaster is essential as it allows the masonry to breathe and evaporate the moisture contained therein.

Slaked lime is a plaster of high breathability for interior use that makes it possible to obtain a highly prized, glossy spatula-formed decorative finish, with hues of mellowed colour shades and depth of texture that vary depending on the application technique and the added colouring materials.

It is primarily used for smoothing onto the finishing plaster when special finishes are desired, such as for stuccos, ground marble plasters or textures typical of classic period decorations. Slaked lime is also used in the restoration of antique stuccos and luxury finishes.

On seasoned plasters, dry and free of dust, at least two layers of product must be laid first to prepare the base thoroughly; then small amounts are applied with a metal spatula or a stainless steel trowel, overlapping the passes to achieve the flecked/dappled effect and the special transparency and chiaroscuros desired.