Felt plaster
Felt plaster as a finishing plaster is a plaster made primarily of lime mortar with particularly finely sifted sand aggregate, which is applied 3–4 mm thick to the dry primer and rubbed off with a regularly moistened felt board . The surface is very smooth after rubbing. This plaster is particularly suitable for small areas. Large, subordinate areas should also be designed with felt plaster. However, one must reckon with fine hairline cracks on large areas, which are clearly visible with such a smooth structure.
Traditionally, pure (air) lime plaster (made from sump lime or white lime hydrate ) without hydraulic components was used. This must be kept moist for a long time and is less prone to cracking because it sets slowly and elastically. Depending on the moisture content and thickness of the application, it is often possible to prevent cracks at the base for a long time after application by solidifying the plaster with a smoothing trowel (compare lime press technique ) and then covering it with the felt board again.