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Deleterious materials – do you know what’s inside your buildings?

Jo Williams / 14 Jan, 20

Two years ago, the use of PIR and PUR Insulation was a common place occurrence in specification in buildings requiring insulation to an external cladding element. Since the Grenfell Tower tragedy this material has become yet another deleterious material and added to the long list of other “black listed materials”.

What exactly is a deleterious material? It is a material that could “cause damage or harm to the individual, the environment or to the buildings and infrastructure”, but people have different views on this and there is still a lot of misunderstanding about what exactly is a deleterious material. Most people would agree that Asbestos is a classic deleterious material as its issues around health and illegal nature are well known. However, there are lots of materials which could potentially be used in the wrong situation or the wrong specification which could also have the potential to become deleterious.

The insulation used at Grenfell Tower is a prime example of where a material, which two years ago was common place is now well and truly in the spot light. Its banned from use in high rise but still available to be used in other circumstances.

So, do you know what is in your buildings? A material which, two years ago was perfectly legitimate to specify, is now not, what other materials are we in a similar situation with? Have all the materials within your buildings been specified to the correct purpose for which they are intended and doing the correct function?

With an increasing number of complex building products available we see more issues such as sick building syndrome where off-gassing, volatile organic compounds and urea formaldehyde are becoming more prevalent in the environments we live in and affecting our health and wellbeing. Whilst firm evidence is low level and often circumstantial for some of these products, the harm to the environment of an oil-based materials and their production is becoming more relevant to how we specify. We need as an industry to be more aware of what we are specifying and the consequences and context of that specification.

Fireproof Expanding Foam is prime example of where materials are often miss-specified. Although a manufacturers data sheet will provide certification that an expanding fire foam has four hours fire protection in accordance with the British Standards, it simply means that it complies to a laboratory test. That’s the legal minimum requirement. There’s no context in the data sheet about ‘how’ that expanding foam needs to be used; adjacent to which materials, thickness, surface preparation etc and how that foam will actually interact in a real-life fire situation.

Similarly, building fabrics such as breather membrane, DPM, DPC, breathable felt, vapour control layers, and foil-backed plasterboard are often specified to control moisture movement in buildings and have gained popularity since their commercial development in the 1980’s. I see these mis-specified again and again leading to the trapping of moisture causing interstitial condensation and thermal insulation problems. Examples include swapping a wall membrane with a vapour resistance of 0.6MNs/g with a roof membrane required to meet 0.25 MSs/g or less. Or specification of roof membranes based on their Brand name only which is far too commonplace. The pitched roof felts available to the market vary between 0.013MNs/g for a popular industry product used by contractors, up to 0.2MNs/g for a well recognised brand. A lot of problems are fortunately therefore avoided by the contractor using a superior (and cheaper) product and not the specified one, and the designer not even realising as they don’t understand what they’ve specified!

There seems to be an over reliance on data sheets and bland marketing statements without a real understanding of what is in our buildings, and a scientific approach to good design.

So, what can we do as building professionals and building users to protect against deleterious materials of the future?

As a building owner or occupier you should be aware of what is in your buildings. Ask your design team to clarify any materials they have specified, is it in the right context, is it harmful to the environment or does it have the potential to cause harm to the building occupants, how does it actually perform in the context of a fire situation? And make sure the correct materials are recorded at the completion of the project.

As building professionals we should be challenging ourselves to specify the most sustainable and safe materials that we can and advising our clients accordingly. If you are concerned about a material and its affects then there are multitudes of sources of information available starting with the manufacturer’s data sheets and British Standards. In the same way as we record asbestos in a management plan within a building, other key materials can also be managed and with the application of common sense have no lasting affects on the building occupants or the environment they exist in. If in doubt, ask a building professional for further advice.

Here at Sanderson Weatherall, we have qualified and experienced design professionals within both Architecture and Building Surveying. We take a cohesive approach to understanding our design and how that fits into your building, whether new or existing. The skills and experience in the design process is not as simple as some people believe, and the added value is often only apparent when things go wrong. Do it properly, get it right first time, and reap the benefits. If you need advice on design or materials then please give us a call.

Topics: Blog

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