When referring to the permeability of building materials, it does not mean air, but water in the form of liquids and gases. Air permeability is often used to describe the passage of water vapor, and various related terms are used to quantify it, such as water vapor transmission rate and equivalent air layer thickness.

Water can affect everything in a building, from the health or destruction of the building structure, to the thermal performance of the building and the health of the occupants. Especially when we try to improve the airtightness, thermal performance and indoor air quality of buildings, air permeability has become a key issue, affecting all aspects of new buildings and renovation projects.

Water vapor transmission rate is the ability of a substance to allow water vapor to pass through. Coatings with high water vapor transmission rate (breathability) can quickly and unhindered release of moisture in the building structure into the environment, avoiding the accumulation of moisture between the coating and the wall substrate, which helps Protect the building structure from damage caused by the accumulation of moisture.

Breathability also provides an aesthetic advantage because moisture can breathe through the coating instead of being trapped behind a dense acrylic barrier coating. If water vapor is trapped, it will accumulate humidity after the coating, which will eventually lead to blistering, peeling and mildew and discoloration of the coating, and even affect the environment due to the growth of microorganisms, producing foul odors and VOCs, and causing putty under the coating. The layer may be saturated with water and its strength will decrease. These surfaces tend to become brittle and pulverize and require frequent repairs.

The coating film of the inorganic silicate coating has a fine finite pore structure, so that the inorganic coating can not only prevent the entry of liquid rainwater, but also allow the free passage of water vapor, so that the wall under the coating can be kept dry for a long time, while also protecting Coating to prevent blistering, shedding, mildew and frost damage.