Cavity wall consists of double walls with a hollow space between them. cavity wall thickness of outer wall and inner wall may be equal or the inner wall may be thicker than outer wall. cavity wall hollow is never exceeds 100mm and it is uniform through the height.
The masonry skins of a cavity wall can be brickwork, blockwork or similar. Different masonry materials can be used on either side of the cavity. The cavity is initially empty but can be filled with insulation by various methods. Cavity walls are more time consuming –and therefore slightly more expensive– to build than walls with the two skins bonded together, but they provide better sound and heat insulation and most importantly resistance to rain penetration.
Typical Flashing Installation at Bearing Support of Cavity Wall
The following advantage s of cavity wall construction
Damp Prevention : cavity wall checks the prevention of dampness from outside to inside of the building in better way than a solid brick wall of same thickness.
Heat Insulation : since air is a bad conductor of heat, a cavity wall decreases the heat transmission considerably hence it is easier to maintain uniform temperature inside the building.
Sound Insulation : sound waves can travel faster in solid media than air, the cavity wall constructions considerably dampens the external noise and inside the building external disturbances have little effect.
Economical : The construction cost of a cavity wall is about 20% less than the construction cost of a solid wall having same thickness.
Disadvantage of cavity walls
- Requires a high standard of design and workmanship to produce a soundly construction wall
- Cavity wall require good supervision during construction.
- The need to a vertical damproof course to all openings
- Slighly higher cost than a standard one brick thick wall.