The third in our series of expert advice on answering tough APC questions

This week's question focuses on building surveying (T006 Building Pathology) and the particular issues around the use of insulated cladding panels. Recent fire incidents have brought an additional spotlight on the issues associated with the use of these panels. Through a relatively technical question the assessors can gauge the candidates knowledge of this particular product in terms of both its direct performance and the wider implications of use.

The Question

  • The sample scenario

You have been instructed by an institutional investment client to inspect three units on a small industrial estate. Your inspection shows the units to be steel portal framed with either exposed aggregate or colour coated steel cladding panels that you notice are relatively thin. The manager of one of the units mentions during your inspection that the cladding panels are foam insulated.

  • The question

Please explain what you understand by the expression ‘foam filled cladding panels’, and the issues associated with the use of such panels.

Behind the Question

This is a question that could be answered at level 1, 2 or level 3. The idea is to generate a short discussion between the candidate and the assessor which would enable the panel to determine what level of expertise the candidate has, and whether this corresponds with the declared level on the forms he and his Supervisor and Counsellor have declared. The candidate should always seek to develop his ideas in an answer of this nature, and to expect some gentle probing to ascertain his depth of knowledge, application of that knowledge and at level 3, their ability to present reasoned advice. Because the question topic has had an element of recent debate, the assessors are also seeking to establish the extent to which the candidate maintains an awareness of current development and issues affecting the industry.


A sample answer at level 1 would involve a conversation with the candidate covering the issues at the following depth:

  • Demonstrate technical understanding In simple terms foam insulated cladding panels are composite panels with an inner insulating element of some type of foam. The foam used is generally Polyurethane or Polyisocyanurate, with a foaming agent to expand the material to fill the internal cavity.
  • Knowledge of related product issues In the past the potential use of HFCs or similar compounds as a foaming agent in the product manufacture has resulted in some buildings being clad with panels that could have significant environmental hazards if damaged or destroyed in a fire.
  • Knowledge of survey limitations Because of the changing composition of the foam infill used over time has arisen from various legislative revisions it is difficult to ascertain the exact nature of the foam in a particular panel infill without intrusive sampling and testing.

A sample answer at level 2 would include an expansion on the above issues to demonstrate the ability to apply the knowledge in areas such as:

  • Reasons for use of product Such panels were generally used because of their lightweight characteristic, coupled with good sound and thermal insulation properties.
  • Building modifications & compliance with current standards It must be remembered that some of the earlier panels, whilst they complied with Building Regulations at the time, will not measure up to current requirements, and these panels may prove to be difficult and costly to remove and dispose of in order to facilitate upgrading to current standards.
  • Deleterious materials & investment Modern foam filled cladding panels are, in the main, produced with colour coated steel panels either side of the infill. Such panels would comply with modern regulations, and can be specified with confidence, although only too often products that were in recent common usage become today's deleterious material. The candidate should be able to discus what is viewed as deleterious and explain why some investors have their own lists of deleterious materials.

At level 3 the answer would move into the area of reasoned advice on issues such as:

  • The context of recent events Greater knowledge should then be demonstrated by demonstrating an awareness of how specific types of panels have been identified as potentially having a contributory role in the consequences of recent fire events in the UK. These issues include their role in the speed at which fire spreads and further discussion into the subject regarding the concerns of some fire fighters regarding the integrity and stability of certain panels under fire conditions.
  • British Cladding Council advice The British Cladding Council called for a moratorium on the use of foam filled cladding panels in 2000, until more research was undertaken on their performance in a fire. Indeed the Council went so far as to urge the use of 'only built up systems or composites containing mineral fibre until the risks associated with foam filled panels have been fully investigated and quantified.'
  • Investment advice Because the client in this instance is an institutional investor, careful investigations would need to be carried out to determine when the panels were manufactured, the nature of the infill and budget costs for their removal and replacement.
  • Insurance implications Other potential concerns such as insuring such buildings also needs to be flagged to the client as the property is being considered for institutional investment purposes.