Last reviewed 17 December 2013
Mike Sopp looks at the important role a building’s façade can play in the overall use of a building.
A building’s façade will provide weatherproofing, insulation and a means of allowing natural lighting to enter the premises. It also increasingly forms a significant part of a building’s overall aesthetics.
However, like all building elements, façades can be subject to soiling and structural deterioration, often accelerated by exposure to man-made pollutants.
To ensure that façades remain aesthetically pleasing, effective in terms of functionality and structurally sound, a well-planned maintenance and cleaning regime will need to be developed.
Soiling and damage
The external soiling and deterioration of building façades can be caused by a wide combination of factors, including age, type and quality of materials, atmospheric conditions, proximity to industrial areas, traffic intensity, etc. Other factors include the angle of inclination of the surface, its texture, and whether it is exposed to the washing action of the rain.
A building façade will look its best when free of grime, pollutants and staining. However, as well as being aesthetically unacceptable, soiling can hide structural defects (such as deteriorated pointing, corroded metal work, local fractures or even major structural cracks). Depending on the amount and the nature of the accumulated substances, heavy soiling can also cause or increase damage to materials.
Contaminants such as sulphur and nitrogen oxides and other acid rain pollutants also serve to accelerate façade deterioration. As an example, moisture, when coupled with soluble salts from polluted rainwaters or atmospheric gases, accelerates decay, particularly to masonry substrates.
Soiling and damage can also be caused by natural elements. Creeper plants, such as ivy for example, can cause persistent dampness on a wall, dislocate rainwater disposal equipment, disturb eaves, copings, dwarf walls or roof coverings and can even cause structural damage to foundations, walls, parapets and roofs.
Damage or deterioration to façade elements can result in water penetration, falling debris and, in extreme cases, façade failure — all of which have the potential to cause harm. Such issues often originate from lack of regular routine maintenance and proper care of the building façade.
The Building Research Establishment notes that all façades require a degree of maintenance if they are to fulfil their intended working purpose and that, in the event of failure, tenants, owners or occupiers could have “a legal liability for personal injury caused to staff, all visitors to your building, and members of the public in the vicinity”.
Any organisation responsible for the cleaning and maintenance of a façade will have to consider a number of factors when determining the regime required. This will require the collection, collation and dissemination of relevant information.
More often than not, the decision to clean a façade will require advice from specialists such as structural engineers and specialist cleaning contractors.
A condition survey of the façade is a specialist but important activity that should be undertaken by suitably qualified and experienced persons, as “to the experienced eye, there may be indications of potential failure, months or even years before the failure actually occurs”.
The survey should identify the age and type of construction, along with materials used, as well as all surfaces requiring access for cleaning or maintenance, including the requirements for replacement of elements of the façade. It should provide information about the extent and severity of any defects or faults and recommendations for remedial works and ongoing maintenance regime requirements.
For newer properties, additional information can be sought from the premises’ health and safety file that will have been developed under the requirements of the Construction (Design and Management) Regulations 2007.
Other legal requirements may have to be given consideration, such as listed building requirements, building regulations and workplace related health and safety legislation. There can be additional influences on cleaning and maintenance, not least:
the location of the property (urban properties may be more prone to soiling and pollutant damage)
the type of amount of soiling taking place
building functionality (eg the need for aesthetics in corporate or public buildings)
building characteristics (eg does soiling add to the overall image of the premises)
building design in terms of issues of access to undertake work
type of cleaning methodology required (eg the disruption and cost involved)
history and impacts of previous maintenance or cleaning work
any necessary consents required to undertake cleaning and/or maintenance
health and safety issues involved with the cleaning and maintenance regime.
Regimes and risk assessments
The above exercise should enable a strategy for maintenance and cleaning to be developed, including frequency of such activities and, where necessary, the methods to be used, although this latter issue may have to be discussed with external contractors who specialise in these activities.
Significant hazards can be created during the course of façade cleaning and maintenance tasks and include working at height, the use of access equipment (eg ladders, scaffolding, scissor lifts, cradles) the use of powered equipment (eg jet washing) and the collapse of fragile structures.
Different methods of cleaning are appropriate for different building façades, depending on their design, quality, condition, building methods and design characteristics and on the nature, distribution and amount of soiling. Methods include water washing, mechanical (dry abrasive) cleaning, air abrasive cleaning, water abrasive cleaning and various types of chemical cleaning, all of which can create hazards.
Although all cleaning methods involve risks to health and safety, chemical methods require exceptionally high care in their application because of the direct and very serious potential dangers they involve.
Risk assessment processes will therefore have an important function in the planning of the maintenance and cleaning work. The factors to be considered in such a risk assessment will include the following:
the work activity (ie the maintenance and cleaning façade)
the access equipment to be used (ladders, cradles, MEWP, scaffolding, etc)
the use of any specialised equipment or substances
the duration of the work
the location of the work activity (eg to determine the presence of hazards to the public)
the work environment (including weather conditions, lighting, space, etc)
the condition and stability of existing work surfaces
the physical capabilities and competency of the workers
emergency procedures required in the event of an incident or accident.
The contracting out of façade maintenance and cleaning is commonplace. The performance of a risk assessment will allow the client to meet its legal duties by collating and passing onto the contractor (when appointed) the necessary information on the risks and control measures required.
The client needs to ensure that the contractor is competent to undertake the work. The levels of competence required of the contractor can be established in the selection/assessment process and that the prospective contractor:
understands the health and safety issues related to façade maintenance and cleaning and has given consideration to preventive and control measures
will comply with relevant legislation, Codes of Practice and guidance
will provide adequate information and instruction to prevent injury to all relevant persons
will ensure proper liaison and contact is maintained with the client before and during any maintenance or cleaning activities.
It must be ensured that contractors have provided a risk assessment of their own and a method statement detailing how they intend to carry out the work. The use of a permit-to-work may also be considered.
BS 8221-1:2012: Code of Practice for Cleaning and Surface Repair of Buildings: Cleaning of Natural Stone, Brick, Terracotta and Concrete
Façade Cleaning: The Removal of Soiling And Paint from Brick and Stone Façades, Westminster City Council
Building Façade Maintenance: Legal Liability and Damage Limitation, Building Research Establishment
Façade Cleaning: For More Than Appearance’s Sake, Hoffman Architects Journal