Base
The base must be undamaged and clean. Old paint, finishing plaster, salt, dust, rust and dense cement paste can be removed by, for example, water sand blasting. A dry surface needs to be wetted, while retaining the absorption capacity of the base. The filler must have properly hardened and be at least one week old before the finishing plaster is applied. Before starting work, apply a test coating to ensure the structure and tint. The tint is affected by, for example, the absorption characteristics of the base, the consistency of the mass, the coarseness of the surface, and naturally the sprayer itself (nozzle size, air volume and the spraying method used). An even flow of plaster from the hose is extremely important for the end result and for that reason you must not let the container run empty in the middle of working.
Mixing
Refer to the bag for how much water the plaster requires. Add the dry material to the water and mix with a concrete mixer for around ten minutes. With a power mixer or a drill paddle, around one to two minutes of mixing is sufficient. Allow the plaster to stand for around ten minutes and mix it again for a short while. Find the correct consistency at this stage by gradually adding the rest of the water. We do not recommend adding all of the water right at the start. Every batch must be mixed in the same way. In order to ensure uniform colour, the different batches should have the same consistency and mixing time. The finished plaster remains workable for around two hours.
Work instructions
Lime-cement coating is normally applied with a plastering pump or a funnel top sprayer, but manual application is also possible. Apply at least two layers. Spray the first layer using more fluid plaster into a layer 2-3 mm thick, depending on the maximum grain size. Allow it to harden for at least one day before the second application. Use somewhat thicker plaster during the second spraying, applying a layer around 1.5-3 mm thick, depending on the maximum grain size. You can create different structures by varying the plaster plasticity, nozzle size, air volume and spraying distance.The more fluid the plaster, the larger the air volume and the smaller the nozzle, the finer the structure. For a plaster sprayer, a suitable spraying distance is around one metre, and for a funnel top sprayer, around 0.6 metres. Spray with circular motions perpendicularly to the surface. Spraying from too close to the surface will easily result in shiny patches. Dark colours require greater care than light colours when spraying. We recommend spraying contiguous surfaces at the same time. You should hide the working seams in corners, expansion joints or, for instance, behind drainpipes. There may be some differences in the colour of different manufacturing batches, so we recommend ordering the required amount of plaster all at once. The water-soluble salts in the cement and the salts formed during the hardening of the lime may rise to the surface with moisture and appear as efflorescence. Efflorescence is caused by rain too soon after plastering, moisture within the structure, thermal leak and insufficient ventilation. The risk can be reduced by protecting the freshly plastered surface from rain.
After treatment
In very dry conditions, the plastered area must be protected with a plastic film or light spraying of water (the water must not flow) for at least one to three days. When the temperature is:
+20°C, protect the fresh plaster from rain and strong sunlight for one day
+10°C, protect the fresh plaster from rain for three days
+5°C, protect the fresh plaster from rain for seven days.
Plastering should be avoided in direct sunlight and in high winds.
Service instructions
A dirty Lime Cement Coating can be cleaned with a pressure washer. Remove any damaged spots and repair the holes. Choose the repair plaster based on the binder-aggregate ratio and strength of the existing, undamaged plaster. Apply the service coating using Lime Cement Coating or Stone Colour KS using a colour chart colour that matches the serviced surface. Before coating, wet the area so that is damp enough to be darker in colour. Carry out the coating work either by spraying or manually, depending on the structure of the maintained/repaired surface, following the work instructions contained in the chosen product's data sheet. You should carry out the finishing very carefully in order not to reduce the adhesion to the base. The repairs may stand out from the original surface as lighter spots before the colour differences even out during use. Keep wetting the repair plaster and coatings for one to three days after the coating work. One or two treatments are required depending on the structure and colour of the surface and the work method used.
Storage and handling of waste
See the separate storage and disposal instructions https://www.fescon.fi/en/material-bank