Kipsilaastit

Kipsilaastit are gypsum-based interior plasters used to finish walls and ceilings. They are mortars whose primary binder is gypsum (calcium sulfate) and that may be supplied as ready-mixed plaster or as a dry powder to be mixed with water. Additives can be included to control workability, set time, adhesion, and final surface properties. Kipsilaastit are common in modern construction for achieving a smooth, even surface ready for painting or wallpaper.

Types and usage patterns vary, but typical kipsilaastit include finishing plasters and bonding plasters based on gypsum. Finishing plasters are designed to form a thin, smooth surface on interior masonry, concrete, or gypsum boards, while bonding mortars improve adhesion between the substrate and subsequent plaster layers. They are often applied in one or two coats, with the final coat planed or troweled to a fine finish.

Application and performance: gypsum plasters are applied with trowels or plastering machines, then compacted and leveled. They set by chemical hydration rather than drying, which allows relatively rapid hardening. Substrates must be sound, dry, and free of loose material; excessive moisture can compromise the plaster. After application, the surface is usually primed before painting or wallpapering. Gypsum-based plasters provide a smooth finish and contribute to interior fire resistance, but are less suitable for exterior use or areas with high moisture unless specially formulated for such conditions.

Advantages include light weight, good one-coat/workability characteristics, and a smooth final surface. Limitations involve sensitivity to moisture and temperature conditions, and the need for proper substrate preparation and curing. Kipsilaastit are a standard choice in Finnish and European interior construction where gypsum-based plastering is appropriate.