In construction, we spend time deciding what materials to use. However, we also spend time focusing on which materials to avoid. Certain materials can or may be harmful to buildings, affecting their structure and performance, and some materials can be harmful to people and these materials must be looked at carefully, following guidelines. Below, we have investigated these materials and their effects.
Materials Hazardous to Health
One of the most known materials hazardous to health is asbestos, which was commonly used throughout the 20th century. However, when asbestos becomes damaged, airborne fibres can be released which may lead to a variety of health problems, including lung cancer, asbestosis and other respiratory illnesses. This led to the use of asbestos being fully banned in 1999.
Lead was historically often used in building materials, such as in paint and water pipes. However, exposure to lead can lead to adverse health effects. Therefore, lead water pipes were banned in 1970 and lead pigments were removed from commonly used paints in the 1980s, although such materials may still remain in some buildings.
Urea Formaldehyde foam
Urea formaldehyde foam was often used in cavity wall insulation and in some insulation board. There is evidence that urea formaldehyde foam causes irritation and is a carcinogen, and use of the material was banned in 1982.
Radon is a radioactive gas and a naturally occurring by-product from decaying uranium, which comes up from the ground into the air. Radon is everywhere, but don’t worry! – It’s usually in insignificant quantities, but concentrated levels can increase in enclosed spaces, and documented health hazards such as lung cancer have been reported.
Volatile Organic Compounds (VOCs)
VOCs are gases that are emitted from items found in buildings, such as furniture, carpets and paint. VOCs are considered toxic substances that can be harmful to people and cause irritation, breathing difficulties and other serious illnesses. Products labelled as containing low VOCs can be used to reduce the effects, along with ventilating spaces well after new products have been installed.
Materials Damaging to Buildings:
Calcium chloride concrete additive
Calcium chloride was commonly used as an accelerating admixture in concreate in buildings constructed before 1977, to speed up the curing process. However, the inclusion of calcium chloride often increased the rate of corrosion of steel reinforcements within the concrete.
High Alumina Cement (HAC)
HAC was primarily used in the construction of concrete within buildings between the 1950s and 1970s, but has been used commercially in the UK since 1920s due to its rapid strength development. As useful as it was in post-war UK, the concrete is susceptible to collapse in areas of high humidity and it was banned from use in 1974.
Calcium silicate brickwork
Calcium silicate bricks were historically used in the construction of some buildings. However, due to their manufacturing process, they are subject to shrinkage. This can often cause cracking in buildings and structural repair methods may need to be considered.
Materials that can have adverse effects on buildings
Magnesium Oxide Boards (MgO Boards)
MgO boards have been used more frequently in construction is recent years, such as for backing to render systems. However, poorly manufactured MgO boards can contain chloride salts and ions, which are hygroscopic and result in the absorption of water into the boards. This build-up of moisture in the boards can leak out and the chloride substances within the water can lead to corrosion to adjacent metal surfaces.
Woodwool slabs were commonly used in the 1960s as permanent shuttering to in-situ concrete, such as below concrete flat roof decks. However, when the concrete was poured, sometimes it was not compacted sufficiently, leading to voids surrounding the steel reinforcement. These voids can remain undetected and the exposed steel is therefore susceptible to corrosion.
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