Internal Surfaces

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Gypsum Plaster

What do we need?

The masonry coating  is necessary because it offers the required protection from the weather (rain, wind, frost, etc.) and air pollution. Alongside covers manufacturing defects, normalizes the facade of the building and highlights its aesthetic. The plaster system of the internal surfaces with ordinary cement based coatings requires preparation of the substrate by spray plaster and applying putty to create a quite smooth surface ready for painting. The procedure increases time of completion of the work and the final cost.

How do we do it?

The application of gypsum plaster  NHP 260 offers within just one day finish surface with excellent aesthetic result, in a single layer, without spary and plaster leveled with putty, ready for painting.

Products used

NHP 260

GLX 290

GLX 298

Anti-alkaline fiberglass mesh for coatings

Galvanized Corner bead with mesh

Step by step

Preparing the substrate:

Ensure that the substrate is dry, solid, sound and free from loose particles, dust, paints, waxes and oils. Cut and remove any protrusions of metallic reinforcement in depth 1 cm from the surface and prime it. Before the start of wetting the surfaces thoroughly with water.

Highly absorbent substrates (e.g. aerated concrete) should be primed with the primer of THRAKON GLX 290. The smooth surfaces, the polystyrene surfaces, low absorbency surfaces (concrete, visible concrete) etc. primed with special primer of THRAKON GLX 298 and if necessary placed special anti-alkaline coatings fiberglass.

Place fiberglass mesh and bridge the different building materials connections such as

  • beams and columns with brick or YTONG
  • cement rings and lintels with brick or YTONG
  • insulating panels (extruded or expanded polystyrene, mineral wool, glass wool) with brick or YTONG
  • polyurethane foam and concrete YTONG
  • electrical and plumbing channels. The plumbing and electrical installation channels are closed with a mixture of cement – sand to protect metal parts from contact with the gypsum. Above channels positioned mesh. On the edges of walls, beams windows and other openings are placed and leveled corner beads, and large wall openings metal guides in order to ensure the alignment of the final construction and the strength of the edges. The corner beads and drivers should be properly galvanized, while application should protect them, otherwise it would corrode with unpleasant consequences.

In walls constructed with aerated concrete or other structural elements are connected by slots and no mud or adhesive, should be given special attention to the gap between them, which should not be more than 5 mm. If you want to plastering on plastic or metal surfaces or on prominent elements (cables, gutters, etc.) must use metal mesh.

In the corners of the openings (doors, windows, etc.) place a strip of mesh perpendicular to the diagonal of the opening. Place also a strip of fiberglass mesh along the lintel and window apron.

The placement of the grid should be  2/3 of the thickness of the plaster to the outside. In practice, this is achieved if first apply a plaster layer NHP 260, then place the grid careful stretched and finally cover with another layer of plaster.

Corner beads:

It recommends using stainless or galvanized anti-alkaline bead, guides or grids to avoid corrosion. Alternatively, you can use corner beads of plastic (PVC). For their support is recommended to use the same material to be used for plastering. The corner beads leveled to ensure, vertical and horizontal edges of the walls.

Plastering Application:

Applied in thickness from 8mm up to 2,5 cm in one hand. If the thickness is greater, is recommended to be applied in two layers. On ceilings the thickness of the plaster should be 8mm – 1.5 cm. The gypsum is preferably be applied with a continuous mixer. Keeping the nozzle of the machine perpendicular to the wall, fill in order from the bottom up the spaces between the drivers, but also other parts of the building. Continuity with the metal bar (in small surfaces with an American spatula) smooth surfaces of the plaster and create flat surfaces. When the plaster pull (after about one hour of application, depending on weather conditions) scrape and align the surface removing excess material. Then spray little water on the surface and rubbed it with a sponge float. After 10 -15 minutes by using metal (American type) spatula smooth the surfaces. In corners (edges and recesses), the corners between wall and floor or wall and ceiling, use the special tools (spatulas and scrapers) in order to ensure perfect edges. After 2 hours, where the surface has hardened spray with some more water and with the metal spatula again smooth the wall, allowing the final surface.

When the plaster is pulled completely (after 10-15 days) can rub the surfaces with special sandpaper (manually or mechanically) so we get a perfectly smooth surface. The plastered surfaces should be ventilated sufficiently to dry evenly.

If on the plaster surface to be fitted tiles, the surface of the plaster is laid on the bar and did not proceed to the next stages of grinding in order to provide better grip. When applying the tile adhesive spread on the plastered and primed surface, and “comb” in the horizontal direction. After plastering:

After plastering, especially during the summer months but also in walls under strong sunlight, you must prevent the rapid evaporation in order to avoid cracks. The plastered surfaces, as is still fresh should be protected from rain, wind and frost, to avoid cracking.

Products used : Plasters & Renders

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