El render, compuesto por una carpeta y arenas, es una piel protectora para muros de piedra o soportes de mampostería y desempeña un papel esencial en el aislamiento y filtrado entre los intercambios higrométricos interiores y exteriores.
The primary function is to ensure the waterproofing of facades. It allows condensation to evacuate through the walls while being impermeable to rainwater. This limits the amount of water that could be absorbed by the wall if it were “bare”. The second function is the aesthetics of the facade: making it flat, homogeneous across its entire surface, and giving it an aesthetic appearance through a particular finish (e.g., brushed, trowelled, scratched render…).
Using natural hydraulic limes makes renders flexible enough to absorb deformations and settlements of walls and foundations. The base of the wall, treated with lime, facilitates the evaporation of capillary rise from the ground. The cornice protects the facade from roof runoff. On an old rubble stone wall, which is laden with moisture, air lime or natural hydraulic lime should be used to avoid cracks, saltpeter, and mold.
En función de la naturaleza de la mampostería, del periodo de construcción e incluso de la ubicación geográfica del edificio (frente al mar, montaña…), es fundamental conocer los soportes y prepararlos antes de aplicar el enlucido o las juntas. La adherencia del enlucido depende de la calidad de este análisis y de la preparación del enlucido.
