What is cladding and how is it used?
Cladding is often called the “skin” of the building. It’s an additional, external layer which surrounds the outside of a building and protects it from the elements. Cladding is usually installed by being attached either directly to the building’s framework or to a layer of battens that stands in-between the exterior cladding and the mainframe. You’ll often find it around roofs, chimneys and windows.
Just like the human skin, cladding is used to cover and protect from external forces. It has water and wind-proofing qualities. It provides additional thermal insulations and it can reduce noise spreading through the walls. Cladding can improve the fire resistance of the building and it can even enhance its appearance.
Regardless of the material, your external wall cladding is made of, it doesn’t require much maintenance. Repairs or cleaning are not needed very often, which makes it a rather cost-effective solution in the long run.
Types of cladding
Depending on the building structure and the aesthetic look you are after, you could go for a variety of cladding. The most common types of cladding include metal cladding, wood cladding, stone cladding, brick cladding and UPVC. Each has its own advantages and disadvantages, which is why it’s worth looking into each type into more detail to make the right choice for your construction project.
Metal cladding is a popular choice amongst building owners because it’s affordable, yet reliable. It has good insulation properties and comes in various styles, textures and finishes, so you can even have a retro brick style effect on your exterior walls.
The most commonly used materials for metal cladding are aluminium and steel. Wall cladding made of steel is just as damage-resistant as it sounds, with steel being amongst the toughest materials. Aluminium, on the other hand, is a good choice for increasing the fire resistance of the building.
When it comes to aesthetics, you can hardly beat the look of a wood-clad building facade. As a natural material, wood cladding creates a classic and cosy atmosphere, while also offering high-end thermal qualities. Timber is great for insulation and with a huge variety of hardwood and softwood to choose from, you can always find an option that fits your budget. Plus, timber cladding is considered the cheapest type of cladding.
For the environmentally-minded property owners, wood cladding is a logical choice, as the materials can be reused if you decide to change the outside wall cladding down the line.
Stone cladding consists of natural or simulated stones, which form a thin protective layer around the outside and sometimes inside walls. It’s a good choice for keeping a balanced temperature, regardless of the season. However, the main appeal of stone cladding hides in its aesthetic properties.
If you choose to have a building clad in slate, marble and sandstone, you can expect a unique and sophisticated appearance of the walls. This makes it a popular choice in architectural design projects.
Brick wall cladding is a classic. Thin brick tiles have been used for insulation of exterior walls for dozens of years across Europe. Even though they provide good weather-resistance, their main benefit is also of an aesthetic nature. Brick cladding allows you to bring a vintage brick look to your property, without having to deal with messy and costly real brick constructions.
Brick cladding can be used for both exterior and interior walls, as it’s a good replacement for wood, aluminium and vinyl. Also, it’s easy to clean and maintain which is a big bonus.
If a contemporary exterior is more your style, then glass cladding is the ideal alternative to brick or stone cladding. It’s easy to install and is a popular design choice for office buildings, as well as residential properties in the city.
Glass cladding is low-maintenance and looks stunning, which makes it more cost-effective than painting, tiling and other high-end decorative methods. With toughened, reinforced, and laminated glass options, it won’t let you down in terms of performance, either.
UPVC cladding is usually at the lower end of the price range for cladding materials, which doesn’t make it any less resistant to the elements. It has great water and wind resistance, so it’s a good insulation material. A modern material such as uPVC gives a contemporary look to the property and can be maintained with simple water and soap wipedown.
The main disadvantage of uPVC is that it has weaker fire-resistant properties than some of the other types of cladding. In the event of a fire, cladding panels made of PVC materials can be combustible, as they usually have a fire-resistance rating of C or D.
Cladding and Fire Safety
Following the Grenfell Tower fire in 2017, concerns have been raised about the fire safety of cladding. Some types of cladding are less fire-resistant than others, with wood and uPVC being more prone to catching fire. However, ACM (aluminium composite material) is considered to be the most combustible cladding. ACM cladding was used in the Grenfell Tower.
Designed as an affordable, lightweight insulation solution, ACM cladding is made up of two skins of aluminium sandwiched around a core material, such as polyethene (PE) or polyurethane (PUR). The problem comes from the fact that these core materials are highly-combustible, turning ACM cladding into a serious fire risk.
In fact, studies have shown that high-density polythene produces 25 times more heat than needed to start a fire. The fact that it’s surrounded by aluminium makes things worse because aluminium has strong heat-conducting properties. So, as the aluminium gets exposed to fire, it heats up, passes heat to the material inside and when the aluminium panel eventually melts down, it exposes the already heated up, combustible, core material to oxygen, causing an accelerated fire spread.
These fire safety issues were brought to the attention of the government, as a result of the Grenfell Tower tragedy. As a result, in 2018, the use of ACM cladding was banned for high-rise buildings (more than 18 storeys) in the UK. Unfortunately, this means that many buildings across the country still have unsafe cladding, which must be replaced. The government has since launched an initiative to help fund the cladding replacement for combustible claddings.
If you are a property owner and you are worried that your cladding may not comply with the new fire safety building regulations, the only way to check is to have a cladding fire safety inspection carried out by a licensed fire risk assessor.
Cladding and the Grenfell Tower disaster
When the 24-storey Grenfell Tower building caught fire on 4 June 2017, it’s estimated that it took only 12 minutes for the fire to engulf roughly 80% of the entire building. Despite the efforts of the firefighters, 72 people lost their lives in the tragic incident.
The initial cause of the fire was determined to have been a faulty fridge-freezer. However, what caused the disastrous outcome was a combination of fire safety issues, resulting from a recent building renovation. Less fire-resistant and insufficient in size, the new windows facilitated the spread of fire to the exterior of the building, while the cavity barriers between the building and the facade were incorrectly installed, causing the fire to spread faster.
The main factors that contributed to the fire taking such enormous proportions, though, were the cladding and insulation installed during the 2012 – 2013 renovation. The Celotex insulation that was put in place was not certified for use with the highly-combustible ACM cladding that it was paired with. This was a major fire safety flaw of the renovation project.
Recent developments in the Grenfell Tower inquiry, however, uncovered that the Reynobond cladding had failed key fire safety tests and yet, the manufacturing company Arconic had still sold it to be used in the Grenfell renovation project. The company reportedly had known about the risks at the time of negotiations. Arconic’s official position is that as the UK market had more lax restrictions on cladding, the product was still suitable for sale.
Since dangerous cladding was banned in 2018, around 274,000 apartments are estimated to require cladding replacement under the new rules. Large residential construction projects, such as these are at a high risk of fire. This is why, to ensure the safety of the workers and the residents, many of these cladding replacement sites have been equipped with top-of-the-range construction site fire alarms by Evacuator Alarms.
Completing the safe renovation of all affected buildings has a projected cost of £15bn. Amidst the crisis, the government approved a £1.6bn fund to increase building safety in 2020. Another £5bn fund is expected to be announced in early 2021. Yet, this is not nearly enough to cover the cost that residential owners are faced with.