These types of materials release substantial quantities of asbestos fibres if disturbed. While RICS members undertaking inspections of properties are likely to be at the greatest potential risk of exposure to asbestos, any other members who visit properties could also be at risk. These include those working in non-real estate-related sectors, such as arts and antiques, who may be searching for artefacts in lofts and other generally unoccupied spaces.
This page explains the difference between sprayed and loose asbestos, where they have been used and their possible risks to surveyors and clients.
Sprayed asbestos
This was used primarily for fire protection and was typically sprayed onto structural steel and concrete soffits. It was often used in areas of high fire risk, such as plant rooms, underground car parks, etc. Thickness can vary from a few millimetres to several centimetres. A lot of this material has already been removed from buildings but often to a poor standard, and it is highly likely that residue or debris will remain in gaps and crevices in the structure.
Sprayed asbestos was also used for condensation and acoustic control. A typical example of condensation control is in a commercial kitchen, where the sprayed asbestos acts as a thermal barrier between a cold external concrete ceiling and the warm, humid air produced by cooking in the room. Applications for acoustic purposes can be found on boiler room slabs or applied to walls and ceilings in cinemas, theatres and telephone exchanges.
Sprayed asbestos is highly friable and can cause significant widespread contamination. Where sprayed asbestos has been applied to structural steels in voids that have been utilised as plenum chambers for mechanical ventilation purposes, the friable nature of the material means extensive contamination of the property is possible. It is unlikely that this will have been identified by an asbestos surveyor.
Loose asbestos
This can be found in many locations. It has not typically been used as a cavity wall insulant but can, in rare circumstances, be found in cavity walls where it has fallen or migrated from use as loft or floor void insulation. More typically, loose asbestos insulation is found in floor ducts or voids where it will have simply been used to provide insulation.
Loose and sprayed asbestos have been used for a diverse range of applications, including the filter media in World War 1 and 2 gas masks, underseal for vehicles, and insulation for buses and train carriages.
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Risk to surveyors
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Risk to clients
While the health risks posed by these materials can be significant, they will also have a considerable cost impact in terms of management, and potentially, removal and treatment. All work on these materials will need to be undertaken by licensed asbestos specialists and will involve high levels of controls, which may impact upon the day-to-day operation of the site. On any site where sprayed asbestos has been removed, carefully consider the effectiveness of this work as it may impact upon the client’s plans for the site. In the past, sprayed asbestos was typically removed by hand, often using wire brushes, resulting in residue being left behind. If encapsulated, this material does not present a risk unless or until it is disturbed. It is usually impossible to remove all this material unless the work is accompanied by the removal of plant and machinery from the area and, if necessary, the use of advanced removal techniques such as abrasive blasting.
It is unusual to find sprayed or loose asbestos in domestic properties, but they do occur in some locations in the UK. Typically, these uses can be traced to occupiers who have worked in the asbestos industry or those that have worked in industries where asbestos may have been removed, for example those refurbishing railway carriages.
Case studies
The client acquires a warehouse site based on known information. This identifies the presence of sprayed asbestos, which had been used several years earlier, and certification was available to confirm removal.
Residue sprayed asbestos post asbestos removal (© Thames Laboratories)
The client commences work on site and concerns are raised by contractors about dust and debris. Analysis of the dust reveals asbestos content. Closer examination of the certification issued following the removal of asbestos identifies several caveats that call into question the quality of the removal works. Subsequent examination on site identifies residue from spayed asbestos on the tops of the structural steels and purlins, as well as within the overlapping sections of roof sheets.
Encapsulated sprayed asbestos identified through use of expanded foam (© Thames Laboratories)
The client is a property manager who, during an audit of a site, identifies sprayed asbestos that has not been maintained in good condition. On examining the site, they discover the contamination of historic books that were stored on the site.
Poorly encapsulated in plenum ceiling void (© Thames Laboratories)
The client, following the purchase of a site, is midway through a refurbishment project and discovers that the removal of sprayed asbestos identified by the previous occupier was not done as expected. Sprayed asbestos residue was left within the joints on a block and beam ceiling. On review of the documentation, this had been noted on the clearance certification but not in the site asbestos management plan.
To complete the works to a sufficient standard, the joints within the block and beam ceiling need to be shot blasted to remove the residue material, resulting in additional unexpected cost and associated project delays.
Sprayed asbestos residue on ceiling (© Thames Laboratories)
