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— Photo: S. Siva Saravanan

Inspect, monitor, maintain: Buildings require maintenance because there are a number of factors working to degrade or wear out their components.

The most common causes of building failure can be traced to one of three causes - poor design/construction, inappropriate repair or neglect.

An example of inappropriate repair might be the use of hard cement mortar to repoint old soft brickwork. Such well intentioned but inappropriate work can exacerbate the rate of decay in brickwork and cause a great deal of damage.

However in most cases neglect is the root of the problem. The inevitable consequences of neglect are blocked rainwater pipes, peeling paint and plants growing in gutters. All these problems will cause excess moisture to get into the brick walls. This, in turn, will eventually cause the masonry to become unstable and vulnerable elements such as timberwork to be attacked by rot or termites.

The weather also plays an important role in the decay of the structures. Prolonged exposure to acid rain due to polluted atmosphere can dissolve bricks and will also corrode metal ties and fastenings. Driving rain can penetrate deep into solid walls where the pointing is missing or decayed. Condensation in a poorly ventilated building can lead to mould growth and encourage rot in timberwork. High levels of moisture and excessive fluctuations in heating can also promote the movement of soluble salts in masonry structures. Salt movement is characterised by patches of white crystals on the surface of walls and can cause considerable damage to plaster and paintwork. Frost can also contribute to decay as the surfaces of old bricks and tiles can shatter if water freezes and expands in their pores. The natural world can have a devastating effect on old buildings too. Tree roots can disrupt foundations and some climbing plants, can be strong enough to force rainwater pipes away from the wall if allowed to grow behind them.

Though often protected by law, animals can also have an impact on buildings. Masonry bees may make their home in soft mortar joints whilst wood boring insects are attracted to warm, damp, unventilated conditions.

More extreme occurrences such as fires or floods can, of course, have devastating effects although these are thankfully rare. It is worth remembering that a constant drip which goes undetected for years may in the end prove to be a more serious and expensive problem. The exterior of the building can be affected by ultra-violet light inducing chemical changes in materials, Pollution, dirt, environments containing salts or other chemicals or gases, thermal movement stressing cladding Freeze-thaw, Water penetration, deliberate or accidental damage and plants.

The interior of the building can be affected by moisture, damage from moveable equipment and people, vandalism, vibration from plant and equipment, normal wears and tears.

The buildings are extended as the income of occupants improves. This usually happens for low-rise residential housing. Problems such as cracks, subsidence, water seepage and leakage frequently occur at the joint parts. Although the extension works are not difficult, very often contractors overlook or fail to ensure the joints between the old and the new buildings are perfectly done. One of the main causes is that the old part is already fully dried up and it absorbs the moisture or water content of the new one and creates gaps for air to penetrate. The longer the problems are neglected further deterioration will occur which invites decay, moulds and fungus to grow, and encourages creepers or trees to grow out of the cracks. The way the structure behaves with time depends on the severity of environment and repair interventions undertaken.

The service life of a structure can be defined as the time period for which a structure in a specific environment under the accepted code prescribed load combinations will retain its properties of service and provide security against collapse in addition to exhibiting an acceptable aesthetic appearance. This service life is closely related to periodic maintenance of the building.

Maintenance is the combination of all the technical and administrative actions, including supervisory, intended to keep the different parts of a building (structural element, cladding, plant, machinery or other component) in, or restored to, a state in which it can satisfactorily perform the functions required of it. It is intended to take care of all the above mentioned problems.

Buildings require maintenance because there are a number of factors continually working to degrade or wear out their components. Eventually, if not maintained, these materials or components will fail because they cannot provide the performance required of them. Structures which are not maintained will fail prematurely or suddenly without warning.

(The author is Emeritus Professor, Department of Civil Engineering, IIT Madras, and former Dean, Anna University)

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