- a stainless steel trowel
- a long stainless steel float
- a drill with a mixer paddle
CRUCIAL to know
- layer thickness = grain size
- for woodworm plasters make 3 min. break before structuring
PART 1: STONE-LIKE & WOODWORM-LIKE PLASTERS
General remarks on plaster application
To avoid discoloration, on one surface use plasters from the same batch number. When plaster is to be applied on armoured layers made of mortars and primed with CT 16, let the substrate dry for 3 days before plastering. Cement plaster substrates must be 28-days old and primed with CT 16 in order to be plastered again.
The application of stone-like and woodworm-like thin layer plasters should be done in the same way:
- on the prepared base coat (primed or not – it depends on the system),
- keeping the thickness of the plaster grain (stone-like plaster with grain size 1.5 mm should be applied on the thickness ca. 1.5 mm),
- with a stainless-steel trowel, or a long float held at an angle of circa 30 degrees to the surface
After applying the plaster and smoothing the surface with a trowel, the excess material should be taken off the wall.
The structuring of all plasters should be done with a PVC trowel, but the way of structuring depends on the type of plaster:
- Structuring stone-like plasters can be done directly after application. Just keep a trowel flat to the surface and make big circles or 8-like moves. As the plaster starts drying, your circles should be smaller.
- Structuring woodworm-like plasters should be done after a short break (ca. 2-3 min.) after the application, in order to avoid sticking material to the PVC trowel during structuring and to improve performance.
If the structuring is vertical, the final smoothing, after the application on the wall with steel trowel, should be done horizontal and vice versa. Avoid crossing the lines coming from application and structuring, this will also influence on the final structure view.
Generally, on one wall, the work should be done without breaks as it increase the risk of having differences in the plaster's appearance, caused by changes in the setting and drying process. Plan your job in such way, so that you take breaks only when the plaster is applied in less visible areas such as— along the edges, facade curves, down pipes, window lines, etc.
Along the expected line of technological break, it is necessary to stick a self-adhesive tape, then apply the plaster and make a structure. Afterwards, remove the tape with some of the remaining material. When the plaster is set, it is necessary to protect the edge of the plaster with self-adhesive tape again on top of already set plaster and apply the plaster on another working area. In the same way it is possible to make joints between different colours and plaster structures.
PART 2: APPLICATION OF MOSAIC PLASTER
Protection of ground level zones
Mosaic plasters are usually applied on the pedestal parts of a building, mostly exposed to dirt, water spillage and damage. Thus, the pedestal parts of buildings should be additionally protected.
Mosaic plaster application
The mosaic plasters, CT 77, should be evenly applied on the substrate at a thickness of one and a half grain size. The substrate should be previously primed with CT 16 Priming Paint in one of the recommended colours.
Spread the mosaic plaster on the surface by holding the trowel as flat as possible. Mosaic plasters don’t need to be additionally structured. The surface should be smoothened with the same tool before it becomes dry. It should not be strongly pressed to the substrate. Do not sprinkle water on the plaster. Do not form the structure. The work should be done on one surface without breaks, keeping the same product consistency.
If there is a need to stop working, the self-adhesive tape should be applied along the break line. Then, the plaster should be applied, structure formed, and tape taken off with the plaster remaining on it. The edge of the applied plaster can be protected with self-adhesive tape.