Technical update: substitute materials


Materials are often substituted during a construction project and this can be due to a variety of reasons, from shortage of materials to value engineering. Substitute materials can be an issue as they often are:

  • Of an inferior quality, performance or durability
  • They do not have the appropriate third party product conformity approval certificate, or are being used out of scope from the approval
  • Individual components from an accredited system have been replaced.  Please Note:  the system outlined in any third party product conformity approval certificate must be exactly the same as what is being constructed on site. Any deviation would invalidate the third party product conformity approval certificate.

Where materials are substituted, it is important they still meet the functional requirements of Appendix C of our Technical Manual. The guidance in Appendix C also states that all products must:

  1. Meet the requirements of British Standards, Codes of Practice or equivalent European Standards current at the time of application, AND/OR
  2. Hold full third party product conformity approval from an independent approval body which is accepted by the Warranty provider. This would either be a UKAS or European equivalent product conformity accredited organisation, which looks at the product/system as whole and reports on its suitability and scope of accepted use.
  3. Where a corresponding Euro Standard exists, bear CE marking in accordance with the Construction Products Directive. This shall be supported by evidence of testing carried out on the product - CE marking is acceptable until 30th June 2025 for construction products to the GB market.


Where materials are substituted it is important they are carefully chosen to ensure they meet the functional requirements of our Technical Manual, in particular ‘Appendix C’. The developer should alert the warranty surveyor of any material substitutions as early as possible. 


Can materials from the original design and specification be substituted?

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Every care was taken to ensure information in this article was correct at the time of writing. Guidance provided does not replace the reader’s professional judgement and any construction project should comply with the relevant building regulations or applicable technical standards. For the most up to date LABC Warranty technical guidance please refer to your risk management surveyor and the latest version of the LABC Warranty Technical Manual.

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