Keim Mineral Paint

Keim mineral paint is TRSC's default protective coating specification for heritage facade conservation where the substrate is mineral (stone, lime mortar, lime render, traditional brick) and conventional acrylic anti-carbonation coatings are inappropriate. The product earns its specification slot for three reasons: (1) substrate compatibility — the silicate chemistry forms a chemical bond with mineral substrates rather than a mechanical film bond, which makes the coating compatible with vapour transfer through the substrate (vital for moisture-managed heritage masonry) and durable against the substrate movement and weathering cycles that produce film delamination on acrylic coatings; (2) UV stability — mineral pigments are UV-stable for very long service life (Keim coatings on European heritage buildings are documented to retain colour and integrity for 100+ years), which is the relevant durability criterion for landmark heritage facades; (3) heritage acceptance — Keim mineral paints have a 145-year track record on European heritage facades and are accepted by major heritage authorities internationally and Australian heritage approval frameworks. The most common specification pitfalls TRSC encounters in the field are: (1) inappropriate substrate — mineral paints require a mineral substrate to develop the chemical bond; substrates previously coated with conventional acrylic, alkyd or vinyl paints will not develop the chemical bond and the mineral paint will fail; the contractor must remove existing paint coatings (by chemical strip, hot air or sandblasting per the manufacturer's recommendation) and verify substrate mineral character before mineral paint application; (2) primer selection — the coating must be applied over the manufacturer-specified primer (Keim Fixativ for porous mineral substrates, Keim Concretal-Lasur for less porous substrates); contractors substituting a generic primer compromise the chemical bond and the published service life; (3) application technique — mineral paints must be applied wet-on-wet to maintain a continuous film; field installations that allow partial drying between adjacent application areas produce visible lap marks that cannot be corrected without re-coating the entire face; the contractor must demonstrate the application technique on a sample panel and complete each face in a single application phase. TRSC heritage facade specifications that nominate Keim mineral paint include the colour designation (matched to the heritage approval brief), the primer specification, the substrate preparation requirements (existing paint removal, substrate verification), and a sample panel approval requirement before bulk work begins. The product was specified on Prince Consort Hotel facade conservation as the protective coating over the Lithomex stone repair and the lime mortar re-pointing.