Where flooring has moved or cupped due to the effects of moisture and heat, there are limited standards that indicate acceptable limits of cupping.
Industry standards for level for laid board exist in some States. These state that the floor shall be finished to an acceptable level surface with no more than 0.75mm vertical gap between the boards in use. However, these generally relate to newly laid floor and not floors that have been subject to excess moisture or heat.
AS 2796 gives only a milled board standard for cupping. Again this is for new boards.
- For all Grades – Cupping of 1mm maximum per 100mm board width.
Boards that are refinished after exposure to excessive moisture or heat are likely to creak. In this case, an elastomeric compound would need to be gunned on to the support joists at the interfaces with the flooring from below the floor. If the moisture content of the boards is still too great after this refinishing, the subsequent continued drying of the boards may result in crowning.
