COMMON BUILDING DEFECTS

In general, there have several building defects which usually occur to building parts such as roofs, walls, floors, ceiling, toilets, doors and windows. (Tan Wei Cheun, 2008). Building difficulty and defect that are regularly found will be discussed in the following section which consists of wall crack, peeling paint, dampness, timber decay, fungi and small plant attack, sagging or deformation, erosion of mortar joint, defective plaster rendering, insect or termite attack, roof defect, and also unstable foundation, and services.

The following are common defects found:

1.        Crack on walls: It is the nature of many construction materials to crack as they age and as they expand and contract, particularly with exposure to moisture as they get wet and dry out alternately. There are cracks in common areas, such as exterior walls, interior walls at corners of doors and windows, and ceilings (usually in the middle). Crack defect have classified of visible damage to walls. There is having different state in category of damage, and degree of damage.

2.        Peeling paint: Peeling usually occurs on building facades, mainly on plastered walls, columns and other areas which are exposed to excessive rain and great dampness. Some buildings that are located near the fadama or water lodging area may face a much higher risk once the signs of peeling paint are visible on the exterior walls. (Md. Kasim N.D, 2009). Peeling paint is always the result of poor surface preparation. The majority of peeling paint problems occurs on surfaces exposed to the rain, sun, and the variation degree of temperature.

3.        Rising Dampness: Dampness is generally defined as unwanted and excessive water or moisture. The existing of dampness in building is one of the most damaging failures that really must be taken care of. It can cause damage in brickwork by saturating them, decaying and breaking up of mortar joints, rotting in the timber structures, defecting by the corrosion of iron and steel materials and also destroying the equipment in the building. Dampness in walls has been taken in consideration in recent years.

Dampness in building originated from a number of sources such as:

a)      Rain: Precipitation can be wind driven that it penetrates joints that remain watertight in normalweather condition. The gutter overflow also can collect and be the aspects of dampness against walls.

b)      Condensation: Humid air condensation on cooler surface or within, or between, building materials also can result to dampness. Air can become humid in several ways, including from the occupants’ water vapours.

c)      Rising damp and flooding: It may be contract with groundwater or floodwater. It also the groundwater may be absorbed by the walls and transported up the wall by capillary action.

d)     Services leaks: It may not just from pipes and tanks, but also the overflowing of condensation forming together with ventilation systems.

e)      Construction process: The construction process too can play its role in this scenario. It is where the process of mixing water to form mixtures that dry out for the construction purpose before the building is functioned, but sometimes by retaining moisture (sealed in by impermeable finishes) that shows and causes problems in the completed building.

f)       Use of the building: This may includes the cleaning of the building, spills, and apparatus leaking.

g)      Moisture in the air: It is in contrast with condensation. Hygroscopic salts can extract moisture from the air in condition that would not allow that moisture to undergo the process of condensation. Dampness comes and goes according with the change of condition. Dampness also may leave stains or traces of mould and lichens and also in certain cases, mosses.

4.         Timber decay: Timber defect are classified into two major groups, non-biological and biological deteriorations. Non-biological deterioration consists of physical decay, excessive moisture content, dimensional instability and chemical deterioration. These defects are mainly caused by the timber in service being subjected to environmental exposure.

Generally, the most common causes of timber decay are as follows:

a)      Design: Usually proven in many older buildings, structural timbers are embedded into external walls and encased into solid floor, which are being the common causes of timber decay.

b)      Alterations: This is regularly seen when sand and cement rendering has been applied to the exterior of the building, trapping moisture and elevating the moisture content of timber window lintels and embedded joints, leading to their decaying.

c)      Maintenance: Blocked gutters, missing roof tiles and leaking pipes will all channel the water to ingress into the fabric of the building, which will then affect timber to decay if the problems are not noticed and restored soon enough.

d)     Wood boring insect: It is a fact to know that old building or home will somehow, have evidences of some form of beetle activity, which will mostly be historic and will have died out years ago.Timber that is used in the building during construction may have high sapwood (high in nutrients) content and have been susceptible to beetle infestation. However, as the sapwood has been depleted and the moisture levels within the timber remain stable, the beetle infestation will die out. The beetle will only infest the heartwood section of the converted timber if it has been modified by fungal decay.

5.            Insect or termite attacks: Termites are small, pale to brownish black in color, insect that capable of feeding on mostly anything including timber. The timber is easily deteriorated if exposed to water penetration, high moisture content and loading beyond its capacity as this greedy and colony-living insect is easily attracted to it. Insect or termite attacks pose a threat to damp and digestible timber found in wall plates, the feet of rafter, bearing ends of beams and trusses. Affected timber can be treated by pressure-spraying with insecticide or fumigant insecticidal process.

6.            Defective plaster rendering: Plaster or render is like mortar coating over the block work. The coating on the inside walls called plaster, then the coating outside the walls called render. Plaster and render is totaling different. The render is generally richer and mostly in cement than the plaster due to weather resistant.

The both of plaster and renders have different function. The plaster insides the walls to make the walls smooth, easy to clean, avoid from insect, and for better appearance. Apart from that, the plasters act as a protection against fire. The other functions are breathable for walls, abrasion resistant, and suitable for decorating or covering with coating, wallpaper and tiles. For the renders, is provided to protect them from the influences of weather.