From cracks to corrosion: How inspectors track down defects in Singapore's buildings

SINGAPORE: Building defects come in many forms, including cracks, corrosion and spalling concrete.For inspectors, the challenge is determining which are minor and which could signal a more serious problem.On top of hands-on checks, they also use drones to scan facades and tiny cameras to look at structural components hidden from view.CNA examines how building inspections are carried out in Singapore, how defects are assessed and what happens when problems are found.HOW BUILDINGS ARE INSPECTED The Building and Construction Authority (BCA), which regulates building safety in Singapore, has two inspection regimes – one covering the structural condition of buildings and another focusing on their facades.Under the Periodic Structural Inspection regime, non-residential buildings are inspected every five years. Residential buildings covered by the regime are inspected every 10 years, excluding landed properties and temporary buildings.Engineers assess critical structural components such as foundations, columns, beams and floors for signs of defects or deterioration.More than 600 buildings were found with structural defects each year from 2023 to 2025, out of more than 7,000 buildings inspected annually, according to BCA data.The authority added that immediate remedial action was taken in those cases.Overall, about 91 per cent of buildings inspected over the three-year period had either no defects or only minor ones.Common minor defects include plaster cracks and water seepage, while more serious problems can include corrosion and spalling concrete.Facade inspections, meanwhile, are required every seven years for buildings that are more than 20 years old and taller than 13 metres.Common minor facade problems include hairline cracks and peeling paint. More significant defects can include spalling concrete and loose cladding panels, which require repair.Regular inspections are meant to identify defects early, so repairs can be carried out before problems worsen, the authority said. A drone being used to inspect the facade of a building. (Image: CNA) DRONES AND AI USED TO SPOT DEFECTSTechnology such as drones and artificial intelligence can support building inspections alongside physical checks.Senior principal engineer Lee Hon Leong of Lee Consultants said drones can be used to photograph building facades, allowing engineers to examine areas that would otherwise be difficult to reach.Thousands of images can be captured during an inspection, with AI used to identify more than 90 per cent of defects, Mr Lee said.Potential defects are then flagged for physical checks. Where necessary, facade inspectors use rope access, scissor lifts or boom lifts to carry out hands-on assessments. A screen showing the live camera feed from a drone during a building inspection. (Image: CNA) Mr Lee said signs that may appear harmless to members of the public can sometimes indicate a deeper problem. Water or rust stains, for example, may be a sign that moisture has entered part of a building.Cracks also vary in severity, and inspectors have to determine whether they are superficial cracks in plaster or affect reinforced concrete.“Peeling paintwork can be quite normal for (a) cement plaster building … but there are cases whereby it is actually deeper than peeling paintwork, so you need a qualified inspector to check and tell the difference,” Mr Lee noted."After the inspection, we will come out with a list of defects and the severity. If it is something more serious that can lead to falling debris, then we will put up a recommendation and method statement telling the owner how to repair it and what's the best way to repair it,” he added.Technology can also help inspectors examine parts of a building hidden from view.For example, a borescope – a small camera that can be inserted into concealed spaces – can be used to inspect structural components behind boards or cladding. A borescope being used to examine a concealed part of a building. (Image: CNA) UNAUTHORISED ADDITIONS PUT BUILDINGS AT RISKPhysical checks are only one part of the process. Engineers also study building plans and records to identify changes made to a property, including unauthorised additions or alterations.Such alterations can increase the loads placed on a building.In January 2025, a mezzanine floor and storage racks collapsed at a warehouse unit at Toa Payoh Industrial Park, trapping three people, including two children.They were rescued by the Singapore Civil Defence Force.BCA later said it had not received any application for the installation of the steel platform and racking system.Mr Lee said unauthorised additions are among the issues engineers look out for, particularly in industrial buildings where heavy machinery can add substantial loads to a structure.Despite such cases, he said Singapore's buildings are generally well maintained."Modern (construction) material seems to be more durable, and the use of stainless steel and corrosion-resistant materials … help in the building inspection and the quality of the building." BUILDING OWNERS URGED TO DO PROACTIVE CHECKSBCA is also encouraging owners to inspect and maintain their buildings between mandatory inspection cycles.CapitaLand, for example, uses robotic crawlers as part of annual inspections of some difficult-to-access spaces above ceilings."They can move around the ceiling freely and give us real-time imaging and data for us to do analysis back on the ground," said Mr Adon Sim, CapitaLand Investment's head of operations, engineering, systems and sustainability.The company said such off-cycle checks complement inspections required by the authorities and help ensure buildings remain safe as they age.Such checks could also help manage maintenance costs over the longer term.“Proactive inspections ensure that defects are identified and rectified before they deteriorate to a more severe state. And in the long run, this will bear fruit in terms of the maintenance costs, life cycle costs,” said BCA group director for building resilience Thanabal Kaliannan. A robotic crawler being used to inspect a difficult-to-access space above a ceiling. (Image: CNA) INSPECTIONS EVOLVE WITH BUILDINGSThe authority's inspection requirements are also evolving as Singapore adopts new construction methods and a wider range of building materials.Different materials may require different inspection methods, Mr Kaliannan said.For example, scanners and borescopes can inspect concealed areas in buildings constructed using prefabricated modules. Timber structures may require instruments to measure moisture levels.These considerations are added to inspection checklists and guidelines for engineers, he added.Another factor is ageing.Older buildings may require more extensive checks as building materials deteriorate over time, Mr Kaliannan said.BCA said its regulations are updated at least every three years, with additional guidelines issued when needed.The authority added that it will continue working with building owners and engineers through dialogues and training to strengthen their inspection and maintenance capabilities.