Why do buildings fail?

In order to answer this question, it is important to acknowledge that buildings are designed and constructed from a multitude of different components, joined and mixed together to form a completed building form that you and I call home or office etc.

Failure mechanism

Through years of use and exposure to the environment, building materials start to deteriorate because of their interaction with heat, moisture and air. Any action of manmade interaction between the buildings can also be described in terms of heat, moisture and air.

Apart from this, a building can further deteriorate through mechanical action, which is the impact of knocks or collision or mechanical action caused by the material and component’s interaction with heat, moisture and air.

The interaction with heat could cause thermal expansion which is a mechanical action due to temperature difference, and chemical degradation due to heat-induced reactions. Heat transfers and migrates through buildings components through 3 means, conduction, convection and radiation.

Water is known to be the main factor for building defects. Water in its various forms affects buildings in different ways but moisture (which is the vapour phase of water) is the state that affects buildings the most as it is everywhere in the environment. Moisture moves in the built environment through bulk water movement e.g. rain, through capillary action, through airborne vapour movement and through water vapour diffusion. Moisture is released from the ground, from humans and animals, from activities such as ironing and boiling, from rain that falls, and moisture is always in the air.

The air, apart from carrying moisture, carries heat, particles, seeds, and spores all of which may affect buildings and its occupants.

The causes of failure

The failure mechanism explains the science behind the failure. What causes failure is a different matter. Buildings have the potential to be susceptible to failure firstly through poor design detailing by the designers. Sensitivity to the climate and potential failure mechanisms is key to designing durable buildings. A building may be aesthetically pleasing but fails miserably if the designers fail to account for the need to keep the buildings dry, easy to maintain and relatively at a stable temperature.

Buildings that were designed well, need to be constructed well following the right specification for materials. The quality of construction materials and strict accordance with construction methods is one of the factors that prolong building durability. Post construction, the building needs to be used as it is intended in the design. Any reconstitution of building use may cause stresses that may affect the building components.

Lastly, maintenance is needed to keep buildings in optimum serviceable condition for the whole building life cycle. Regular cleaning may seem simple but plays a key role in avoiding component failure and defects in the long run. Maintenance needs must be designed together with the building design, in such a way that components may be regularly inspected and replaced through preventive maintenance, or building components that are not serviceable will need to be designed with the ultimate service life consideration.