Gypsum board-surface treatment: Moisture protection capability (NT BUILD 344)

  • Report #: NT BUILD 344
  • Approved: May 1989
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The purpose of this test method is to determine the moisture protection capability of a surface treatment on gypsum board. The testing is carried out with a view to estimate the moisture protection of layers applied to gypsum boards behind wall coverings consisting of ceramic tiles, since it cannot be taken for granted that such coverings – in particular the joints – are waterproof. This also applies to the jointing between the tiles, even if this has been very carefully executed and with a special grout. Water inevitably penetrating the joints can only evaporate through the joints between the glazed ceramic tiles or diffuse through the wall to the other side of the wall. The consequence hereof will be that even walls briefly exposed to water-spraying will remain wet for a considerable period of time. It is therefore important that the materials behind the ceramic tiles either are not influenced by water or that the materials are protected by a special waterproofing layer.


The test method is used to examine the extent to which a waterproof layer between a gypsum board and a ceramic tile protects the gypsum board against moisture when used in shower rooms.

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