When constructing a new building or a home, the choice of wall construction is significant. Among the comprehensive range of options, cavity walls are often preferred in many construction projects.
They consist of two layers of masonry filled with an airspace between the inner and outer layers. They offer several advantages to structures, like enhancing energy efficiency and regulating indoor temperature. Additionally, these walls provide exceptional structural support, prevent moisture from penetrating the walls, and insulate the building.
Cavity walls present an innovative solution to the problems associated with traditional solid masonry walls. To know more about cavity walls in detail, continue your reading:
What are Cavity Walls?
Cavity walls are constructed with two layers of masonry that are separated by a cavity.
The gap between walls is referred to as “leaf” and is usually filled with insulation material. The outer layer is called “outer leaf,” while the inner layer is called “inner leaf.” A cavity wall, also known as a hollow wall, can be constructed using concrete blocks or bricks.
Purpose of Cavity Walls
Cavity walls are an indispensable part of modern construction, used for several essential purposes, including:
Thermal Insulation: One of the primary functionalities of a cavity wall is providing thermal insulation. As mentioned earlier, the space between the inner and outer leaves is filled with insulation material, which helps to reduce heat transfer. It keeps the building warm in winter and cool in summer.
Sound Insulation: The cavity wall is specialised in maintaining certain degrees of sound insulation property. It typically restricts voice transmission from the outside world to the inside of the building and vice versa. This is especially suitable for urban areas, where privacy is a major concern.
Prevent Moisture: It is well known that moisture can cause a lot of damage to the building. It may lead to leakage or mold growth. With cavity wall construction, you can prevent entering rainwater into the inner leaf by deviating directly from the outer leaf downward.
Construction of Cavity Wall
A cavity wall may not require any footings as deep as for solid walls. In some cases, it is essential to ensure structural stability. Both the inner and outer layers are constructed normally, with a minimal cavity in between them. By filling the bottom of the cavity with some concrete, it can provide additional support.
The inner leaf is constructed with normal bricks, while the outer lead is made with facing bricks. The bottom of the outer leaf is equipped with weep holes at intervals of 1 meter. Both the inner and outer leaves are connected by wall ties or metal ties, which are completely rustproof.
They are made from steel and available in different shapes. The maximum vertical spacing between the leaves is 450 mm, whereas the horizontal spacing is 900 mm. Beyond all functionalities, these wall ties don’t allow moisture inside the space.
When requiring one brick thickness or more, a Flemish or English bond is used. Similarly, the stretcher bond is used for half-brick thickness. While laying bricks, using wooden battens at suitable dimensions instead of cement mortar ensures preventing mortar from dropping in the cavity.
Applications of Cavity Wall
Cavity walls are used in various applications, such as:
- Cavity walls provide flexibility in material choices and offer versatile design options
- Act as an energy-efficient insulation in buildings
- Prevent mold formation through leakage of moisture content.
- Adapt various construction methods and masonry types.
- Excellent sound insulation property, quite suitable for urban areas.
- Resistant to water penetration and prevention of dampness
- Provides thermal insulation for a comfortable environment
- Maintains good structural stability
Advantages of Cavity Wall Construction
Here is a list of advantages provided by the cavity wall:
Sound Absorption
- Sound insulation, or soundproofing, is a technique used to restrict the amount of noise that travels from an outdoor environment to an interior space.
- It is significant in both residential and commercial settings to enjoy extreme comfort and privacy.
Damp Prevention
- Damp prevention is essential to creating a healthy, hygienic, and comfortable living environment.
- Enhanced dampness leads to the development of a wide range of problems like structural damage and mildew growth. Therefore, being aware of these proactive measures prevents dampness from occurring.
Efflorescence Prevention
- When the masonry surface or surface of concrete is supposed to meet water-soluble salts and other materials, efflorescence can occur.
- They finally leave a white or grayish powdery deposit that leads to the deterioration of the surface.
Increased Durability
- The use of metal ties or wall ties between the two layers of masonry provides excellent stability and strength to the walls.
- They prevent cracking and other severe structural problems.
Disadvantages of Cavity Wall Construction
Sediment and Dirt Collection
Older buildings contain sediments such as flaking mortar, dirt, debris, and other materials in the cavity.
Such sediment may lead to thermal bridging, which affects the significant advantages of cavity walls.
Expertise Assistance
Cavity wall construction may seem simple when hearing out. But it needs an experienced mason to handle and lead the project in the possible right way.
Though you are ready to spend on the project, choosing an experienced craftsman is important to do the job.
Where to Construct a Cavity Wall?
Cavity walls can be used in both residential and commercial locations, as some of the common places are listed here:
Doors or Windows Opening: When constructing a cavity wall around window and door openings, extra care and attention must be taken. These areas are generally called reveals; this special attention is to ensure providing structural stability, insulation, and weather resistance.
Roofs: Cavity walls are the best choice for roof construction. It typically provides structural stability, soundproofing, and insulation. They are constructed between rafters filled with insulation material that improves energy efficiency and prevents heat loss in the building.
Parapet Wall: It is a low wall that extends above the roofline of a building. The height of parapet walls can vary, with standard practices suggesting a minimum height of approximately 30 inches (or 2.5 feet) for flat roofs. Building codes often require heights of at least 36 inches (or 3 feet) to ensure safety and provide wind protection. Cavity walls are constructed between the inner and outer layers of the wall and filled with insulation material. While used in parapet walls, they provide excellent insulation, and structural strength, elevate aesthetic features, and soundproofing. It protects the roof membrane and insulation from rain, wind and other weather drawbacks.
Final Thoughts
Cavity walls are a superior choice in various types of building construction. It can be used in a variety of areas for an efficient and comfortable living environment. By using cavity walls in buildings, we can make the project durable and cost-effective.