The cavity walls are provided for following purposes:
- Damp Prevention:
Cavity walls eliminate the penetration of moisture from outer leaf to the inner leaf and thus help keep inside of the building free from dampness.
- Thermal Insulation:
The air in the cavity wall acts as a non-conductor of thermal heat and hence minimizes the transmission of heat from the external face of the outer leaf to the internal face of the interior leaf. Thus cavity walls help greatly in the thermal insulation.
- Sound Insulation:
The air in the cavity acts as a cushion for absorbing sound, by adopting cavity walls buildings may be rendered sound proof as considerable external noise gets absorbed in the cavity.
- Efflorescence Prevention:
As dampness is not allowed penetrate by cavity, the inner wall of the cavity which is always a load bearing wall is kept free efflorescence effects.
Cavity walls are found to cost about 20% less than the construction of same thickness solid wall.