Understanding cavity walls is essential for creating warm, energy-efficient homes. Cavity walls help keep the inside of the house at a comfortable temperature while saving money on heating and cooling. In this article, we’ll explain what cavity walls are, how they work to keep homes warm, and what materials can be used to improve their performance. Whether you’re building a new home or renovating an old one, this article will explain how cavity walls can improve your home’s comfort and efficiency.
See also: Cavity wall insulation: How to save energy and cut costs?
Meaning of cavity walls
Cavity walls are special because they’re not just like regular walls made of bricks or concrete. They have two layers with a gap, or space, in between them. This gap is like a little pocket of air. This design brings some good things for people who own homes. They offer a unique double-wall system with an air gap in between, providing a range of benefits for homeowners.
Firstly, the gap in the middle helps to keep the inside of the house warmer when it’s cold outside and cooler when it’s hot outside. It’s like a buffer zone that stops the outside weather from affecting the inside of your home too much. This means you don’t have to use as much energy to heat or cool your home, which can save you money on your energy bills.
Secondly, because there’s this extra layer, it can also help with keeping noise out. So, if you live in a noisy area, having cavity walls can make your home quieter and more peaceful.
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Components of cavity walls
A cavity wall consists of several key components that work together to provide insulation, strength, and protection for buildings. The outer skin, which faces the exterior of the building, is typically made of masonry materials like bricks or cinder blocks. This layer serves as the first line of defence against external elements such as weather and impacts.
Inside the cavity wall, there’s the inner skin, which can be constructed using various masonry units such as concrete blocks, structural clay, brick, or reinforced concrete. This inner layer adds structural integrity to the wall and provides additional insulation for the building.
The cavity itself is the air space between the outer and inner skins. This gap plays a crucial role in regulating temperature and moisture levels within the wall. During hot weather, the cavity helps to keep the interior cool by preventing heat from transferring through the wall. In colder conditions, it acts as a barrier, reducing heat loss from the building.
Metal ties or bonding blocks connect the outer and inner skins together, strengthening the wall and ensuring its stability. These ties are usually made of corrosion-resistant materials like stainless steel to withstand environmental conditions.
To prevent water from penetrating the wall and causing damage, a water-resistant membrane is applied on the inner side of the cavity. This membrane acts as a barrier, directing water out of the wall and protecting the structure from moisture-related issues such as mould and rot.
Finally, weep holes are small openings located at the base of the wall system or above windows. These holes allow any water that has accumulated within the cavity to drain to the exterior, preventing water buildup and potential damage to the wall structure. Overall, the components of a cavity wall work together to create a durable, efficient, and weather-resistant building envelope.
Source: Pinterest
Working of cavity walls
In a cavity wall, there are two walls, sort of like layers, with a gap in between. Imagine it like this: the outer layer is like the face of the building, usually made of bricks or stone, while the inner layer can be made of different stuff like bricks, concrete blocks, or wood, depending on what’s needed for strength. These two layers are connected by metal ties to keep everything steady and strong.
Now, the important part is that space in the middle, the air cavity. This gap does two main things: it helps to keep the inside of the building at a nice temperature and it also stops water from getting inside. So, when it’s hot outside, the air in the gap stops too much heat from getting in, and when it’s cold, it helps keep the warmth inside. Also, if water somehow gets past the outer layer, the gap acts like a shield, stopping it from reaching the inner layer and causing damage.
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History of cavity walls
Cavity walls have been around since ancient times, like in Greece and Rome, but people stopped using them for a while. They made a comeback in the 19th century and became really popular in the United Kingdom in the 1920s. In the 20th century, they started using metal ties a lot to hold the walls together better. This made the walls stronger and more stable. Then, in the 1970s, they started adding insulation to the walls. This made buildings warmer and saved energy. By the 1990s, laws said that buildings had to have insulation in their cavity walls.
Construction consideration
When building a cavity wall, there are a few important things to think about.
Firstly, the width of the gap between the two layers of the wall is crucial. This gap usually measures between 25mm to 50mm (which is about 1 to 2 inches). This space is needed for two reasons: to allow any water that gets in to drain away properly, and to help keep the inside of the building at the right temperature.
Secondly, sometimes builders add insulation material into this gap to make the wall even better at keeping the building warm. This can be especially helpful in colder climates.
Lastly, there are rules and regulations that builders need to follow when making cavity walls. These rules cover things like what materials to use, how wide the gap should be, and making sure there’s enough ventilation. These rules are there to make sure the walls are safe, strong, and energy-efficient.
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Is this the right choice for you?
Benefits in different climates
- Cold Climates: Cavity walls are great in colder areas because they keep the inside warmer by trapping heat.
- Wet Climates: In places with lots of rain, cavity walls help manage water, keeping the inside dry.
Saving energy
- Cavity walls help save energy by keeping heat inside. Adding insulation makes them even better at it.
Considering costs
- Building cavity walls can cost more at first because of extra materials and work.
- But in the long run, they can save money on energy and repairs.
Maintenance needs
- You need to check and clean cavity walls regularly to make sure they work well.
- If you’re okay with that, cavity walls can be a good choice.
Fire safety
- Cavity walls aren’t as good at resisting fire as solid walls because of the gap.
- Make sure your building meets fire safety rules.
Insulation limits
- There’s only so much insulation you can add to a cavity wall because of the gap.
- If you need lots of insulation, you might need to look at other options.
Finding reliable contractorsÂ
Ask locally for referrals
When searching for reliable contractors to build cavity walls, start by asking friends, family, or neighbours who have recently undertaken construction projects. They can offer valuable recommendations based on their own positive experiences with contractors in the area. Local referrals often provide insights into the quality of workmanship and the reliability of contractors.
Conduct online research
Utilise online resources to find contractors specialising in cavity wall construction in your locality. Platforms like Google, Yelp, or local business directories can provide reviews and ratings for different contractors. Additionally, check if the contractors have a professional online presence, such as a website or social media profiles, to learn more about their services and reputation.
Check credentials
Before finalising your choice, ensure that the contractors are licensed and insured. A valid licence demonstrates that they meet local regulations and standards, while insurance coverage protects you and the workers in case of accidents or damages during the project. Request to see their licence and proof of insurance to verify their credentials.
Interview multiple contractors
Contact several contractors and discuss your project requirements with them. Inquire about their experience with cavity walls, previous projects they’ve completed, and if they can provide references. Ask about their approach to insulation, materials used, and quality control measures to assess their expertise and suitability for your project.
Visit completed projects
Whenever possible, visit completed cavity wall projects carried out by the contractors you’re considering. This allows you to observe firsthand the quality of their workmanship, attention to detail, and overall finish. Examining past projects can help you gauge the contractor’s capabilities and determine if they meet your standards.
Request detailed quotes
Ask each contractor to provide a detailed written estimate for your project. The quote should include labour costs, material expenses, insulation specifications, and any additional services they offer, such as damp-proofing or weep hole installation. Review each quote carefully to understand the breakdown of costs and services provided.
Compare quotes and references
Compare the quotes you receive from different contractors, considering both the cost and the quality of services offered. Additionally, reach out to the references provided by the contractors to inquire about their experiences working with them. Hearing firsthand accounts from past clients can help you make an informed decision.
Establish a contract agreement
Once you’ve selected a contractor, ensure that all the project details and terms are clearly outlined in a written contract. The contract should cover aspects such as the project scope, timelines, payment schedules, and warranty details. Having a formal agreement in place helps protect both parties and ensures clarity throughout the construction process.
Trust your instincts
Ultimately, choose a contractor you feel comfortable working with and who inspires confidence. Trustworthy contractors prioritise safety, quality, and customer satisfaction. Take your time to research and choose wisely, trusting your instincts to guide you towards the right professional for your project.
FAQs
The gap typically ranges from 25mm to 50mm (1 to 2 inches) for optimal drainage and insulation.
Yes. The air gap significantly reduces heat transfer, leading to lower energy consumption and cost savings on heating and cooling.
The cavity allows moisture to drain and escape, preventing buildup within the wall and reducing the risk of mould and dampness.
Yes, the air gap acts as a sound barrier, making your home quieter and more peaceful.
The air gap can potentially slow the spread of flames, improving fire resistance to some extent.
Adding a cavity wall to an existing structure is typically not feasible due to extensive structural modifications required.
Solid walls with thicker insulation or advanced insulation materials can be options depending on your priorities and climate.
Reduced energy consumption translates to lower carbon footprint and a more sustainable home. How wide is the air gap in a cavity wall?
Are cavity walls more energy-efficient?
Do cavity walls prevent moisture problems?
Are cavity walls good for soundproofing?
Are cavity walls more fire-resistant?
Can I add a cavity wall to an existing house?
What are the alternatives to cavity walls?
What are some environmental benefits of cavity walls?
| Got any questions or point of view on our article? We would love to hear from you. Write to our Editor-in-Chief Jhumur Ghosh at jhumur.ghosh1@housing.com |
