What Is a Cavity Wall?
A cavity wall consists of a hollow space between them. The cavity walls normally consist of two skins, which should be brick, cinder blocks, or reinforcement concrete blocks, etc. The absorbent materials are used in cavity wall construction to that draw out the rainwater and consist of humidity in the wall. The weep hole is constructed above the window or base the wall to draw out the rainwater.
A cavity wall also known as a hollow wall is a wall constructed with an air space or cavity between two separate walls called the outer wall and inner wall. The air space provides insulation against energy loss (thermal conductivity). Cavity walls are built for many reasons, but the chief advantages of cavity walls are that they provide protection from extremes of weather such as heat and moisture as the cavity insulation with the damp proof course makes a building warm in winter and cool in summer.
They act as fire breaks to prevent the spread of fire across the building and they are relatively cheap to build. Cavity wall is constructed with two separate walls for single wall purpose with some space or cavity between them. These two separate walls are called as leaves of cavity wall. The inner wall is called as internal leaf and outer wall is called as external leaf. Cavity wall is also called as Hollow wall.
It is joined together by metal ties and at suitable intervals and separating by an air space. The cavity wall generally is an exterior wall but sometimes it’s used as an interior wall. The weep holes provide an air circulation system in the cavity walls that help to Come out of the evaporated water outside of the cavity. Approximately two meters apart at the base of each story, a weep hole is created by separating several vertical joints.
How to Build a Cavity Wall?
To leaves of the masonry wall separated by an air gap and tides by ties is known as a cavity wall. This section will explain how to build a cavity wall. The cavity walls normally consist of two skins, which should be brick, cinder blocks, or reinforcement concrete blocks, etc. It is joined together by metal ties and at suitable intervals and separating by an air space. When it is construed as a non-load bearing wall then the two skins of the cavity wall are maybe the equal thickness. As required, sometimes the inner wall is thicker than the outer wall. The weep holes provide an air circulation system in the cavity walls that help to Come out of the evaporated water outside of the cavity. Approximately two meters apart at the base of each story, a weep hole is created by separating several vertical joints.
Cavity Wall Detail:
The cavity wall detail is termed as skins. It is contained two layers of masonry like a bricklayer or concrete layer reinforcement concrete etc. It is joined together by metal ties and at suitable intervals and separating by an air space. The cavity wall generally is an exterior wall but sometimes it’s used as an interior wall. If it is a non-load bearing wall then the two skins of the cavity wall are maybe the equal thickness. To fulfill the structural requirements sometimes the internal skins are thicker than the external skins. At least four to five ties are used at each square meter to provide an adequate bond between the inner and outer skins of the cavity wall. A flexible vertical damp proof course should be provided at the doors and windows reveals to prevent the entry of moisture in the room. The width of the cavity wall should not more than 100 mm and not less than 40 mm. To protect from rust the mild Steel is used that is galvanized or dipped into hot tar or sanded. The vertical distance and a horizontal distance of ties should not exist 450 mm and 900 mm. Sometimes a DPC should be provided to prevent the damp between the walls. The damp-proof course was made of lead, pitch, asphalt, and slate. At regular intervals at the steel or wrought iron wall ties are used to tide two half of the walls.
Cavity Wall Construction Details:
When an air space or hollow area is exits between the two walls, then it is called a cavity wall, showcasing the cavity wall construction details. The inner wall is generally made of masonry, like bricks, cinder blocks, concrete blocks, reinforcement blocks, etc. The humidity into the wall and the rainwater slowly draw by the masonry because it is an absorbent material. Another system of the cavity is to drain water through the weep holes lies above the window or base of the wall. The weep holes provide an air circulation system in the cavity walls that help to Come out of the evaporated water outside of the cavity. Approximately two meters apart at the base of each story, a weep hole is created by separating several vertical joints. The cavity holes are provided above the window because it prevents dry rot of wooden window frame. It is commonly referred to provide both sides of the cavity walls.
Cavity Wall Foundation Detail:
The cavity wall foundation detail involves the cavity portion between the top of the foundation concrete and the ground level being filled with 1:2:4 at least 150 mm below DPC. Under the two leaves separately, DPC is provided. The rainwater has access to drain out the outside of the leaves by the weep holes. The cavity walls are existing up to the concrete bed. Just below the floor level with a damp-proof course, the cavity extent up to the base of the footing. If the brickwork below the ground level is not correctly done, then the water enters from the joints and reaches up to the cavity causes dampness in the wall.
Cavity Wall Thickness:
The wall that is provided as a non-load bearing wall, with specific cavity wall thickness, and that walls are hollow is called a cavity wall. The two leaves of the cavity wall are equal thickness. Sometimes the inner wall is thicker than the outer wall. The double walls of the cavity wall are 260 or 275 mm thick according to the building codes. The inner and outer walls of the cavity wall approximately 102.5 mm thick, consider 65 to 70 mm thick. Sometimes the inner wall should be increased to 215 mm or more when the floor is to be supported, or a heavier load is acting.
Internal Walls Construction:
The walls that divided the building into many compartments or created a private space is called internal walls or partitions walls. They can provide privacy, acoustic, fire resistance, and flexibility of layout. The partition wall may be hollow or solid, and it is constructed of bricks, cinder blocks, or RCC concrete blocks. It can be a form of frame structure like timber, steel, or aluminum frame clad with timber board, steel board, metal, or fiberboard. Sometimes the internal wall may be glazed. Sometimes it is used as a load-bearing wall and create a designer modular system.
Brick Cavity Wall:
The cavity wall we can construct by many things that should be bricks, RCC concrete blocks, or cinder blocks, often resulting in a brick cavity wall.
Brick Cavity Walls:
The cavity walls are made of two brick walls or leaves called brick cavity walls. In the two leaves or walls of the brick, a hollow space is a lie that is called a cavity. The weep hole is constructed above the window or base to draw out the rainwater from the brick cavity walls. It is joined together by metal ties and at suitable intervals.
Cavity Wall Insulation Pros and Cons:
In building construction, there are have many pros and cons to cavity wall insulation, including cavity wall insulation pros and cons. But there have more pros than cons-
Pros of Cavity Wall Insulation:
There are have many pros to cavity wall insulation –
- It controls the atmosphere in the house.
- It helps to keep the house warm in winter and cool in summer.
- it’s reduced the monthly electricity bill to reduce the uses of the room heater or air conditioner.
- The polystyrene bead is used as an insulation material that is so small so it can pump easily if even the cavity is lean.
- The loss of heat in the winter season should be reduced by using cavity wall insulation. Space between two walls is work as a lid that prevents the escaping of heat from the house.
- The material that is used in cavity wall insulation is cheaper and recycled materials.
Cons of Cavity Wall Insulation:
There are have some cons of the cavity walls insulation –
- Sometimes the cavity wall insulation cost is increased by using expert workers or special tools to inject the cavity with insulation materials.
- The risk of an inexperienced installer is another disadvantage of cavity wall insulation. The poor work of the inexperienced installer makes the wall damp.
- The cost amount of cavity wall insulation depends on the cavity or gap between the internal and external walls.
- If the width of the cavity is so small then the heat is not properly balanced in winter and summer.
- This cavity wall construction does not apply to all houses.it is not used in old buildings where the wall is solid.
Frequently Asked Questions (FAQ) about Cavity Wall Construction
What is a cavity wall?
A cavity wall, also known as a hollow wall, is a type of wall constructed with an air space or cavity between two separate walls called the inner and outer walls. This air space provides insulation against energy loss and helps protect the building from moisture and temperature extremes.
What materials are used in cavity wall construction?
Cavity walls are typically constructed using materials such as bricks, cinder blocks, or reinforced concrete blocks. Metal ties are used to join the two walls at suitable intervals, ensuring stability and integrity.
How does a cavity wall provide insulation?
The air space between the two walls acts as an insulating layer, reducing thermal conductivity. This helps keep buildings warm in the winter and cool in the summer, contributing to energy efficiency.
What are the main benefits of cavity walls?
Cavity walls offer several benefits, including:
- Improved thermal insulation
- Protection from moisture and weather extremes
- Enhanced fire resistance
- Cost-effective construction
- Reduced energy bills due to better temperature regulation
What is the purpose of weep holes in cavity walls?
Weep holes are small openings constructed above windows or at the base of walls to allow rainwater and evaporated moisture to drain out of the cavity. This helps prevent moisture buildup and potential dampness inside the walls.
