What properties should coatings applied to a wall made of sand-lime bricks have??
Such coatings must be alkali-resistant and show good adhesion and flexibility, also at low temperature. They must be easily permeable to water vapour, resistant to light and changing weather conditions, in addition, have hydrophobic properties.
After what time, counting from the erection of the lime-sand brick wall, can be performed:
a) impregnation?
b) covering coating?
Impregnation of a sand-lime brick wall can be done no earlier than after 4 weeks after the wall was erected. On the other hand, the covering coat can be made on the sand-lime brick wall only after 3 months after the wall was erected.
What should be the value of the sd factor (the equivalent thickness of the air layer corresponding to the water vapor permeability) in the case of a sand-lime brick wall. Please justify this condition
For coatings applied to a wall made of sand-lime bricks, the value of the sd coefficient should be below 0,4 m. If the coating has a higher diffusion resistance, it can cause moisture retention in the outer zone of the wall. During frost, this can additionally cause the material to chip and fall off.