Hygienic requirements to construction materials

The outer walls of the buildings are made of various natural or artificial materials. These materials should be strong, have thermal insulation and soundproof properties. The insulating properties of materials depend on the thermal conductivity of them (and the ability to conduct heat and heat capacity (ability to absorb and retain heat).
The thermal conductivity of the material depends on the porosity. The more porosity of the material, the lower the thermal conductivity, as the air trapped in the pores, is a poor conductor of heat.
The thermal conductivity and heat capacity of the material are inversely proportional. The higher the conductivity, the lower the heat. Building materials with high thermal capacity heat up more slowly, but slowly lose absorbed heat.
From a hygienic point of view, an important property of construction materials is hygroscopicity (ability to absorb and retain moisture). Currently, the use in the construction of such materials is prohibited.
In addition, construction materials must possess the necessary durability, fire resistance and not allocate indoor air toxic substances.
During the construction of multi-storey buildings often use solid or hollow brick, small and large units and special panel.
For low-rise construction is often used wood with a small conductivity. The negative feature of wood as a building material is its susceptibility to rot and easy Flammability.
To prevent destruction of the tree house mushrooms timber treated with antiseptics (creosote, fluoric sodium and others). In order to protect the timber against fire, they are impregnated of flame retardant substances.
The inner walls are built of wooden boards or other maloznakomyh materials and plaster.