9.30.2.2.(1)

Intent 1:

To limit the probability:

• of inadequate rigidity of underlay panels, or
• that the performance of underlay will fall significantly below expectations.

This is to limit the probability that the underlay will be unable to bridge any irregularities in the subfloor and will telegraph them to the finished flooring, which could lead to the displacement or cracking of finished flooring.

Where finished flooring is required to provide water resistance, this is to limit the probability of the ingress of water into the subfloor, which could lead to compromised structural integrity of the supporting structure, which could lead to an inability to resist expected gravity loads, which could lead to structural collapse, which could lead to harm to persons.