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Question

How long can structural floor boards for timber joists be left exposed on site?

Consideration

When considering how long structural floor boards can be left exposed on site, it’s important to consider the functional requirements, which state:

• All materials should be stored, installed and protected correctly in a manner that will not cause damage or deterioration of the product
• All materials, products and building systems shall be appropriately tested and approved for their intended purpose

With this in mind, structural floor boards should be stored, installed and protected as per the manufacturer’s instructions. However, as structural floor boards are built in as the work proceeds they may be left exposed to the elements and they will be subjected to various issues, especially during prolonged periods of precipitation.

Answer

For warranty purposes, structural floor boards for timber joists that are to be installed as the building proceeds and left exposed must have a third party product approval certificate which covers weather resistance for the period of time the boards are to be left exposed on site.

Any boards that are left exposed beyond the period stated in the third party approval certificate should be replaced.

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Every care was taken to ensure the information in this article was correct at the time of publication (September 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-3210