Last edited 04 May 2021

Deleterious materials in construction

The term 'deleterious materials' is a broad one, encompassing not only materials that are dangerous to health or which are the causes of failures in buildings, but increasingly, materials which are environmentally damaging. Lists of deleterious materials may be prohibited in appointment documents or construction contracts.

It should be noted however that all materials can be considered deleterious under the wrong circumstances (for example, water can be very damaging and can cause extensive pollution), and whatever materials are selected for use, it is vitally important that the manufacturer's instructions are followed.

The following materials are commonly considered to be either harmful to human health or to be the cause of long-term failure in buildings. While some of these materials may now be considered to be 'banned', they can still be found in our historic building stock.

Asbestos and Asbestos Containing Materials (ACM): Asbestos is often found in products such as cement fibre boards and roofing and sprayed as fireproofing or insulation. There are strict regulations controlling its removal and disposal (see Asbestos for more information).
Brick slips: These can be made from deleterious materials. There is a risk of poor adhesion and the lack of 'soft joints' can transfer loads to slips and cause delamination.
Cadmium products.
Chlorides: Calcium chloride and sodium chloride.
Chlorofluorocarbons (CFCs), Hydrochlorofluorocarbons (HCFCs) and Hydrofluorocarbons (HFCs) are considered to be 'greenhouse' gases.
Coal tar.
Lead and Lead Containing Materials (LCM) are hazardous materials which are neuro-toxic. Lead in paint is far more widespread than is realised. HSE guidance states: 'if preparing paint work, lead surveys' are a requirement for pre-construction information. Residual leaded exhaust particle contamination can also be found in floor, ceiling and roof voids. Working with LCMs creates a 'significant' exposure risk, from inhalation and ingestion, as defined by lead regulations.
Hair plaster
High alumina cement: Used as an accelerator for quick setting of concrete.
Urea formaldehyde: Used in furniture and foam products or contained in adhesives.
Urea formaldehyde foam: Used in cavity wall insulation and some insulation boards, however this is not very common in the UK.
Polychlorinated Biphenyls (PCBs).
Polyisocynurate or polyurethane foam.
Marine sea dredged aggregates (not in compliance with BS EN 1260): Such aggregates may contain salts, such as sodium chloride. If the salts are not washed out there is a risk of corrosion of concrete reinforcement.
Mercury, which can now be found in Compact Fluorescent Lamps (CFLs)
Machine Made Mineral Fibres (MMMF): If the fibres have a diameter of 3 microns or less or a length of 200 microns or less.
Mundic, which is a condition that occurs (especially in homes built from 1900 to 1960 in Cornwall and Devon) when structures deteriorate due to the oxidisation of unstable sulphides (often including pyrite) used in concrete.
Pentachlorophenol: Most commonly found in paint and wood preservatives.
Silica dust. Stone, brick, tile and concrete contain silica. Silica dust (known as Respirable Crystalline Silica (RCS)) can be inhaled and can lead to silicosis, a lung disease that causes permanent disablement and early death. See HSE: Control of Substances Hazardous to Health (COSHH) for more information.
Vermiculite, unless fibre-free: Vermiculite can be found in light-weight concrete, fire protection materials, paints and other coatings.
Volatile organic compounds: Found in paints and protective coatings.
Wood wool: Slabs are often used as permanent formwork and left as a ceiling soffit. This may result in reduced fire resistance, reinforcement corrosion or in extreme cases, loss of structural strength in its use as a permanent shuttering or formwork.

The list of deleterious materials has always remained fluid because as technology advances new products come onto the market and medical research establishes new risks to health.

Clauses in contracts and appointment documents often refer to compliance with 'Good Practice in the selection of construction materials'. Originally published in 1997 by Ove Arup, and sponsored by the British Council of Offices (BCO) and the British Property Federation (BPF), it was an attempt to standardise a chaotic situation where contracts included long lists of prohibited materials that were often not deleterious, or were not enforced.

Now in its 2011 edition, 'Good Practice in the selection of construction materials' has been updated to reflect changing standards in materials specification and the growing importance of environmental concerns.

Asbestos

The following is a more detailed list of components where the use of asbestos might be detected (ref. list published by Greenhalgh & Co, Chartered Surveyors):