Structural floor boards for timber joists and their weather resistance


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.


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. 


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

Download a PDF version of this article

Download a pdf version of this article

Download a PDF version of this article

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.

Ref: TS-3210

Related Articles

Panelled roof cassettes

Don't miss the deadline for submitting product approval documents when using roof cassettes on LABC Warranty sites. Read more...
Read More

Rain gardens

The design, positioning, and maintenance requirements around the use of rain gardens.
Read More

Key risk areas for gable spandrel panels

Key risk areas when using gable spandrel panels on sites covered by LABC Warranty.
Read More