Base
The base must be undamaged, clean, and damp enough to be darker in colour. There must be no cement paste on the surface. Remove damaged concrete, for example by chiselling or milling. After removal, make sure that no partially damaged concrete remains on the surface. If necessary, water sand blast the surfaces and finally pressure wash them. The target level of cleanliness is class 3. Clean reinforcement bars to cleanliness class Sa2 and pressure wash them. We recommend protecting the rebars immediately with Fescon Adhesive Plaster. Reinforcement according to the designer's instructions. Begin wetting the base on the previous day. The required amount of wetting depends on the weather conditions and, for instance, the strength of the base. Bases with a high strength require more wetting. You must always ensure that there is no standing water on the base when starting rendering. Use Fescon Adhesive Plaster for manual repairs. When spraying plaster on a base with adhesion difficulties, for example due to water absorption or smoothness, use Fescon Adhesive Plaster.
Mixing
Total water requirement is around 3.6 l/25 kg of dry product. Add the dry material to the water and mix with a power mixer for around one to two minutes allow to stand for five minutes and mix again for a short while. Find the final consistency at this stage by adding water when necessary. However, keep the total amount of water at around 14.4% of the dry product. The finished plaster remains workable for around one hour.
Work instructions
When applying the compound manually, press it particularly carefully to the base. Use the adhesive plaster with the wet on wet principle. Apply deeper fills in layers so that the previous layer has had time to harden for at least one day. In machine application, use sufficiently powerful pumping equipment to apply the compound, for example, a plastering pump. If necessary, test to ensure that the equipment is suitable. The recommended layer thickness for a single spraying is 3-10 mm. You can use thicker fills when patching individual cavities.
After treatment
The lowest working temperature is +5°C. Nor should the temperature be allowed to fall below this during aftercare. The aftercare must be begun immediately after the plaster has been spread and must continue for at least five days. We recommend plastic covers and/or hood. The aftercare is stopped in stages. Naturally, the SILKO guidelines shall also be followed during aftercare.
Storage and handling of waste
See the separate storage and disposal instructions https://www.fescon.fi/en/material-bank