tencuial

Tencuial, also known as plastering, is a building technique in which a cohesive mix is applied to a substrate to form a protective and decorative surface on walls and ceilings. It can be used on interior surfaces for a smooth finish or on exterior façades as weatherproof render. The plaster is typically applied in layers and finished with a trowel or float.

Materials and mixes: Traditional lime plaster uses lime putty mixed with sand; cement-based plaster uses cement, lime, and sand; gypsum plaster uses gypsum and water; modern plasters may combine cement, lime, gypsum, polymers to improve adhesion and flexibility. Substrates include brick, block, concrete, wood lath, metal lath. Surface preparation and bonding agents improve adhesion.

Application, process: The substrate is prepared, dampened; a bonding coat or scratch coat is applied to create a key; a second base coat is applied; a finish coat is applied and troweled to desired texture. Curing conditions must be controlled to avoid cracks. Tools include trowels, hawk, float, combs for textures. Exterior tencuial often called render and may be reinforced with mesh in areas prone to movement.

Performance and uses: Provides protective layer against moisture and temperature fluctuations; enhances thermal mass and acoustic properties; can be colored and textured. Breathability is a consideration; lime-based renders are more breathable than cement-based ones.

Maintenance and problems: Cracking, spalling, dampness, and efflorescence can occur if moisture is present or substrate movement; repairs involve removing damaged plaster and reapplying with compatible materials; large repairs may require partial removal and re-plastering.

See also: plaster, stucco, render, lime plaster, cement plaster, gypsum plaster, masonry.