InSite | New guidance on prefabricated products

New guidance on prefabricated products

Published date: December 18 2023

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What are the warranty concerns?


Offsite manufactured prefabricated false chimneys, dormer constructions, canopies and more recently external mouldings such as feature corbelling products are being marketed, some with and some without third-party product conformity accreditation.


For those products and systems that do hold third-party approval certificates, there is often no evidence of durability or weather resistance to satisfy our warranty functional requirements.


As well as this, the installations of some of these products and systems on site have either been found to not follow the manufacturer’s approved installation recommendations design, or there is little consideration to how the product interacts with the adjoining construction, particularly in respect to resisting weather resistance or movement. In some instances this has led to water penetration through to the structure occurring which required remediation works post completion.


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What we require to mitigate risks


For our warranty purposes, we require that any proposed off-site manufactured product or system used as part of the structure or water proof envelope of the building must be appropriately tested and approved for their intended purpose.


To satisfy that requirement, all prefabricated glass fibre false chimneys, dormer constructions, canopies or external mouldings must have a valid third party product approval issued by a UKAS or European equivalent product conformity accredited organisation which is accepted by us.


What information is required?


The documents required for individual site specific review must include:


1. A valid third-party product conformity approval which identifies the product, its intended scope of use, what exposure environment conditions the product/system have been tested to. The approval certificate should also clearly identify what has been tested and performance achieved. There should also be confirmation that the manufacture of the product/system has been carried out under a recognised quality management process.


2. For warranty purposes where such products/systems are to be used on our sites, they must be clearly identified at the start of a project and a full specification including the third-party certification documentation be made available to our warranty surveyor.


3. The developer/builder must also demonstrate that they will follow the manufacturer’s installation procedure details as identified in the third-party approval. These details should be made available to our warranty surveyor upon request.


4. Where a product/system is used within 5km of the coastal shoreline anywhere in the UK, the product and any metal fixings used must be appropriately durable for the aggressive environmental conditions and meet the service life requirements in our Technical Manual.


5. All components used in manufacturing of the product/system should satisfy Appendix C of our Technical Manual.


Transitional arrangements 

At the time of publication (December 2023), in order to transition this requirement, we will be requiring for all warranty plots commenced after the following dates that manufacturers of the above products and systems will:


• From 1st January 2024 to 31st August 2024 have appointed a third party product conformity body to commence a formal assessment. A statement of intent from the UKAS (or European Equivalent) product conformity accredited organisation should be provided to the warranty provider upon request.

• From 1st September 2024 to 31st May 2025: Only manufacturers products that have engaged a third party Product conformity body and formally commenced assessment will be accepted on our Warranty projects.

• From 1st June 2025: All such products used must have a valid published third party product conformity certification in place.


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Every care was taken to ensure the information in this article was correct at the time of publication (December 2023). 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 Premier Guarantee technical guidance please refer to your Risk Management Surveyor and the latest version of the Premier Guarantee Technical Manual.
Ref: TS-3671