MAT.31/54

CategoryFinishes and Coatings

ClassMineral Paint

Updated10/06/2026

Scala 1:1

Technical Sheet — A

A.01A.02

Material N°31

SilicatePaint

Mineral wall finish based on potassium silicate. Unlike plastic paints, it does not form a film but chemically bonds to the plaster via silicatisation, guaranteeing unrivalled breathability and durability.

B.01

StratigraphySECTION A-A

The crystalline chemical bond prevents the blistering typical of acrylic paints subjected to vapour pressure or rising damp.

C.01

Reference standard

DIN 18363

Max 5% organico

C.02

Vapour permeability

< 0.01 m (Sd)

Altissima traspirabilita'

C.03

Bond type

Chimico

Silicatizzazione

C.04

Alkalinity

~ 11 pH

Biocida naturale

C.05

Fire reaction

Classe A1

Totalmente incombustibile

C.06

VOC emissions

< 1 g/l

Eco-compatibile

Description

Created in the 19th century to emulate the durability of medieval frescoes, silicate paint uses liquid potassium silicate — so-called 'liquid glass' — as its binder. Its physico-chemical behaviour makes it the perfect ally of mineral architecture and historic restoration.

01The silicification bond

Most of today's paints (acrylic, styrene-based) adhere to the wall like a glue, forming a surface plastic film. Silicate paint, on the other hand, penetrates the pores of the substrate and reacts chemically with the calcium salts present in the render. This reaction — silicification — generates an insoluble microcrystalline structure of hydrated calcium silicate. The paint is no longer an added coating: it physically becomes part of the wall itself.

02Breathability, healthiness and limits

Having a crystalline structure similar to that of sand, this finish allows almost 100% of water vapour to pass through (Sd < 0.01 m), preventing the detachment caused by internal moisture. Its strongly alkaline pH (~11) acts as a natural fungicide and algaecide without releasing biocides into the environment. Its only limit is compatibility: silicification occurs only on bare mineral substrates.

Technical identity

Standards

European and international references applicable.

DIN 18363 sez. 2.4.1CAM EdiliziaNatureplus

Physical properties

UV resistanceAssoluta (colori stabili nel tempo)

Thermal expansion coefficientPari al supporto minerale (no distacchi)

Smog and acid resistanceElevatissima

Dirt pick-up tendencyBassissima (nessuna componente termoplastica)

Usage environment

Silicatisation occurs only on bare mineral substrates (lime plaster, cement, stone, brick). It is not compatible with surfaces already coated with acrylic or washable paints.

A — 01

Documented applications

TAV. D

D.01

Historical plaster restoration

Ideal finish for restoring old lime plasters, keeping their hygric permeability intact.

D.02

External insulation (ETICS)

Final coat for breathable external insulation systems in rock wool or wood fibre.

D.03

Exposed concrete facades

Thin protective wash (Lasure) for reinforced concrete columns and facades, preserving the material texture.

D.04

Bio-construction interiors

Nursery, hospital and bedroom walls with zero VOC emissions and natural protection against mould and algae.

Vapour Permeability (Sd value in metres — lower Sd = more breathable)

TAV. E

Silicate Paint (this material) — microcrstalline bondCrystalline bond — zero film: vapour passes freely through mineral microcrystals

Sd < 0.01 m

Lime Wash (natural, traditional)Very breathable mineral binder: excellent but without the durability and UV resistance of silicates

Sd ~ 0.03 m

Siloxane Paint (resin + silicone)Hydrophobic but breathable film: good compromise but ages with plastic film degradation

Sd ~ 0.10 m

Acrylic-Quartz Paint (plastic film)Plastic film slows drying of walls: condensation risk in old masonry with rising damp

Sd ~ 0.50 m

Synthetic Enamel / Washable Paint (vapour barrier)Virtually impermeable: traps moisture inside walls causing blistering and mould in damp environments

Sd > 1.00 m

An Sd value below 0.14 metres identifies a highly breathable material. Acrylic paints trap moisture in the wall, causing plaster detachment under thermal cycles or capillary rising damp.

Used in these processes

TAV. P

PRC.06Load-bearing Wall in Porous Clay Block→

Used in these systems

TAV. S

S-41Cork ETICS→S-26Mineral-wool ETICS→S-38Wood-fibre ETICS→S-19Aerated concrete (AAC) block wall→S-03Porous clay block wall→

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