A building’s façade is not merely an aesthetic covering; it serves as a protective skin, shielding the internal structures from the elements. However, various factors, ranging from improper installation to environmental and biological impacts, can compromise the integrity of a rendered façade. Here we will delve into the multiple elements that can potentially impact a rendered façade and how to mitigate them.
Improper installation
Inadequate preparation
The substrate’s inadequate preparation, such as improper cleaning or priming, can lead to poor adhesion of the render, resulting in debonding and cracks. The façade, when not properly adhered, cannot withstand environmental stresses, leading to premature failure.
Incorrect mixture
Incorrect mixture proportions or using contaminated water/materials can compromise the render’s structural integrity and durability. The improper mix can lead to a weakened façade, susceptible to cracks, and may allow water ingress, causing further damage.
Unsuitable weather conditions
Applying render in extreme temperatures or humid conditions can lead to improper curing, reducing its lifespan. This can result in a myriad of issues such as cracking, efflorescence, and diminished bonding strength.
Inadequate curing
Curing is essential for the strength and durability of the render. Inadequate curing can lead to a lack of cohesion within the render, making it prone to cracks and other forms of structural degradation.
Mitigation
Employ experienced and qualified professionals who understand the intricacies of the installation process and can adhere to best practices. Strict adherence to the manufacturer’s guidelines can ensure the correct mixture proportions and application methods, optimising the render’s performance. Also, ensure that the rendering is performed under suitable weather conditions and that adequate measures are taken to facilitate proper curing. After installation, regular inspection can help in identifying and rectifying any deficiencies in the installation before they escalate into major issues.
Weather exposure
Extreme temperatures
Fluctuating temperatures, especially in areas with distinct seasons, can cause materials to expand and contract repeatedly, leading to cracks and eventual structural failure. Prolonged exposure to extreme heat can cause discolouration and degradation of material properties.
Heavy rainfall & moisture
Water is one of the most damaging elements for any building façade. Persistent moisture can infiltrate cracks and pores in the façade, leading to mould, rot, and corrosion, and can eventually compromise the structural integrity of the building.
High winds
High winds, especially in storm-prone areas, can exert excessive pressure on the façade, leading to its deformation or failure. It can also drive rainwater into small openings, exacerbating water damage.
Ultraviolet radiation
Prolonged exposure to the sun’s ultraviolet rays can degrade façade materials, leading to fading, chalking, and loss of mechanical strength, especially in polymers and paints.
Ice and snow
In cold climates, the accumulation of ice and snow can place additional weight and stress on the façade. The freeze-thaw cycles can also cause cracks and spalling in masonry and concrete structures.
Mitigation
Selecting materials that are resistant to the local weather conditions can mitigate the damage caused by weather exposure. Frequent inspections and prompt repairs of any weather-induced damages are crucial in maintaining the façade’s integrity and appearance. Applying weather-resistant coatings can provide an additional layer of protection against UV radiation, moisture, and temperature fluctuations. Designing the façade with proper overhangs and shields can protect it from direct exposure to rain and sunlight.
Biological growth on the rendered façade
Mold and fungi
Mold and fungi thrive in damp and humid conditions and can cause severe health issues in addition to damaging the façade. They can degrade the materials, leading to stains, unpleasant odours, and a reduction in the façade’s structural integrity.
Algae and moss
Algae and moss typically grow in areas with high moisture levels and can cover extensive sections of the façade. Besides being unsightly, they can also retain moisture against the building surface, leading to further water damage and deterioration.
Lichen
Lichen, a symbiotic association of algae and fungi, can be particularly damaging as it secretes acids that can corrode building materials, leading to discolouration, and can eventually compromise surface integrity.
Insects and rodents
Façades can also become a harbour for pests like insects and rodents, which can cause additional damage by gnawing and nesting within the structures, as well as creating potential health hazards.
Mitigation
The application of fungicidal and algaecidal coatings can prevent the growth of mould, algae, and other biological entities on the façade surface. Frequent cleaning and removal of any visible biological growth are essential to maintain the façade’s aesthetic and structural integrity. Ensuring that the façade can ‘breathe’ and does not accumulate moisture is crucial in preventing the conditions favourable for biological growth. Implementing pest control measures can help in preventing infestations and the subsequent damage caused by insects and rodents.
Mechanical impact on the rendered daçade
Accidental impacts
Accidental impacts from vehicles, construction equipment, or falling objects can cause immediate, visible damage to the façade, such as cracks, dents, and punctures, compromising its structural integrity.
Vandalism
Graffiti, etching, or other forms of vandalism can cause irreversible damage to the façade surface, affecting the building’s appearance and value. Cleaning or removing such damages can sometimes lead to further degradation of the façade materials.
Wind-driven debris
In areas prone to high winds or storms, wind-driven debris can act as projectiles, impacting the façade with considerable force, causing scratches, dents, or cracks and may lead to water ingress and other complications.
Construction and maintenance activities
The façade can suffer mechanical damages during construction, renovation, or maintenance activities due to negligence or accidents, leading to costly repairs and restoration.
Mitigation
Utilising durable and impact-resistant materials can minimise the damage caused by mechanical impacts. Installing barriers, bollards, or other protective elements around the building can prevent accidental collisions between vehicles and equipment. Prompt detection and repair of any mechanical damages can prevent the escalation of localised damages to more severe structural issues. Applying anti-graffiti coatings can make it easier to clean vandalised surfaces without causing damage to the underlying materials.
Design flaws
Inadequate consideration of climate
Failure to consider local weather conditions, such as rainfall, temperature fluctuations, and wind loads during the design phase can lead to the selection of unsuitable materials and construction methods, resulting in poor performance and reduced lifespan of the façade.
Incorrect material selection
Choosing materials that are not compatible with each other or are unsuitable for the intended application can lead to a range of problems such as differential expansion, corrosion, and debonding, impacting the façade’s durability and appearance.
Poor detailing
Insufficient attention to detail, especially at joints, transitions, and penetrations, can lead to water ingress, air leakage, and thermal bridging, compromising the building’s energy efficiency and structural integrity.
Lack of provision for structural movement
Failure to accommodate structural movements due to temperature changes, settlement, or seismic activity can result in cracks and deformation in the façade, leading to water ingress and structural damage.
Mitigation
Comprehensive analysis of local climate, site conditions, and material compatibility is crucial during the design phase to prevent flaws that can compromise the façade. Regular reviews and stringent quality checks during the design and construction phases can help in identifying and rectifying design flaws early on. Involving façade consultants and structural engineers in the design process can ensure that the design is structurally sound, durable, and fit for purpose. Conducting thorough testing of materials and design prototypes can help in verifying their performance and suitability under anticipated conditions.
Pollution
Airborne pollutants
Airborne pollutants such as sulfur dioxide, nitrogen dioxide, and particulate matter from vehicle emissions and industrial activities can adhere to the façade surfaces. These pollutants can react with the materials, leading to corrosion, staining, and material degradation.
Acid rain
Pollution-induced acid rain can have detrimental effects on the façade, causing erosion and decay of building materials, especially limestone, marble, and concrete, affecting the building’s structural integrity and appearance.
Dust and grime accumulation
Accumulation of dust and grime on the façade can lead to discolouration and can act as a medium for microbial growth. It can also obstruct façade details and features, diminishing the architectural aesthetics of the building.
Chemical spillage
Chemical spillage and residues from industrial processes can lead to severe damage to the façade materials, causing discolouration, corrosion, and structural weakening, necessitating extensive repairs and renovations.
Mitigation
Frequent cleaning of the façade can prevent the accumulation of pollutants, maintaining the aesthetic appeal and structural integrity of the building envelope. The application of protective coatings can shield the façade materials from the corrosive and degrading effects of pollutants. Choosing materials that are resistant to corrosion and degradation from pollutants is crucial, especially in areas with high pollution levels. Incorporating design features such as overhangs and shields can protect the façade from direct exposure to rain, reducing the impact of acid rain and pollutant deposition.
