Mold growth and moss growth on tropical walls

To Coat or Not To Coat: A question on porosity and coating in building material

“…In specific circumstance where the evaporation is not happening, the water within the material will start to affect the material structure. It will start to create dampness and moreover, water and the porosity, together, could invite microbial organisms to start inhabiting the material [12,15,20]. Problems such as mould, moss, and surface loss that are caused by water containment within the material could be considered as a pathological symptom of the building [17].…”

“…In accordance with this issue, the use of porous material [2,[4][5][6][7] and the use of coating [1,8] has become the "passive" alternatives to reduce the energy consumption for thermal control. Nevertheless, the majority of researches on building material and coating tend to solely focus on the technical and physical properties of the building material and coating [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. This paper focuses instead on developing a core understanding of the different kinds of porosity and coating across building materials that influence the building performance.…”

“…Some researches address how porous materials provide transporting ability that support passive cooling through evaporation, moisture and heat transfer [2,[4][5][6][7][9][10][11] while coating supports the thermal control due to its reflectance toward heat source radiation (sunlight) [1,8]. However, in many context, porosity is also considered as the beginning of degradation and deterioration of building material that become the parameter of its durability [12][13][14][15][16][17]. The porosity of building material is associated with the durability of the material, and coating often becomes the response toward this durability issue.…”

“…The use of coating to maintain durability is mostly related to avoid water and moisture containment that could generate pathological problems for the building material such as dampness, microbial growth, material loss, etc [12,15,[17][18][19][20]. Coating suggests the act of covering something; in building material, it usually covers the surface.…”

“…Coating suggests the act of covering something; in building material, it usually covers the surface. Coating generally aims for protection, mostly against water [13,17,18,21], even though some other aims, such as hygiene [21] and aesthetic [14,15,19] are also relevant. A coating on the surface of porous building material usually decreases the porosity and roughness of the surface [12,14,19] to shield the permeability of the material.…”