Saturday, September 17, 2022


  • Fungal stains or mould occur when there is moisture content in the walls.
  • It flourishes in an environment of high humidity with lack of ventilation.
  • Harmful growth includes creeping and ivy plants that can grow either on walls, roofs or gutters.
  • This usually happens when dirt penetrate small openings in the walls and mortar joints, creating suitable grounds for seeds to grow.
  • Roots can go deep into the existing holes causing further cracks and water penetration.

  • The main function of a mortar joint is to even out the irregularities of individual blocks either stones or bricks.
  • Causes of mortar joint erosion include salt crystallization, scouring action of winds, the disintegrating effects of wall growing plant, and water penetration resulting in dampness.
  • Decayed mortar can be forcibly removed with a mechanical disc or manually racked out using a knife or spike.

  • Peeling paint usually occurs on building facades, mainly on plastered walls, columns and other areas that are exposed to excessive rain and dampness.
  • Some buildings located near the sea may face a grater risk.
  • The amount of constant wind, rain and sun received can easily turn the surface of the paint to become chalky and wrinkled or blistered.
  • As is the case in many heritage buildings several layers of paints have been applied onto the plastered walls over the decades.
  • Apart from lime wash, other types of paints used include emulsion, Oil-based, tar, bituminous and oil bound water paint.
  • Different types of paints require different methods of removal depending on their nature.

  • Defective plastered rendering occurs mostly on the external walls, columns and ceiling.
  • In a humid tropical climate like Malaysia., defective renderings are normally caused by biological attacks arising from penetrating rain, evaporation, condensation, air pollution, dehydration and thermal stress.
  • Other causes may be the mould or harmful growth, insects, animals and traffic vibration.
  • Prior to being decomposed and broken apart, renderings may6 crack due to either shrinkage or movement in the substrate.
  • External walls may be harmful to a building if they are structurally unsound. Vertical or Diagonal Cracks in the wall are common symptoms of structural instability.
  • Such defects should be investigated promptly and the causes diagnosed : be it the foundations weak materials and joints : or any shrinkage or thermal movements such as those of timber window frames.
  • Diagonal cracks, usually widest at the foundations and may terminate at the corner of a building, often occur when shallow foundations are laid on shrinkable sub-soil which is drier than normal or when there is a physical uplifting action of a large tress's main roots close to the walls.
  • Common causes of leaning walls include a spreading roof which forces the weight of a roof down towards the walls, sagging due to soil movement, weak foundations due to the presence of dampness, shrinkable clay soils or decayed building materials ; and disturbance of nearby mature trees with roots expanding to the local settlement.

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