Factors Influencing the Service Life of Buildings

The service life of a building depends mainly on its chief structural materials and the environment it is placed in. This paper collates the evidence from condition surveys conducted on some buildings with ages of up to 125 years set in a humid tropical environment, and seeks to arrive at some generalizations. Load bearing masonry walls and timber floors had performed well, as had exposed steel sections that were well maintained. Buildings with such elements could be expected to last well beyond the 'normal' design life of 60 years. If a reinforced concrete building had been exposed to a chloride source, major repairs were required after just half this design life. Carbonation depth was found to broadly obey a correlation with the square root of time. However, it is shown that both depths of carbonation and surface chloride levels can vary considerably in different parts of the same building. These findings have direct implications for both construction (in the choice of materials) and inspection (with respect to sampling and use of multiple test methods).