Abstract: Lightweight construction panels, such as gypsum plaster-board, are commonly used to provide internal partitions in buildings It is known to cover, either partially or fully, the panel with an aqueous material such as gypsum plaster or jointing compound. It has been found that known panels expand when they absorb water. This gives rise to several undesirable results such as the gypsum plaster or jointing compound cracking as the panel expands as moisture is absorbed. The present invention provides a panel comprising a gypsum matrix including fibres in an amount of at least 0.8 wt % relative to the gypsum, a polymeric additive in an amount of at least 0.8 wt % relative to the gypsum, and at least one phosphate additive. A panel having such a composition has been found to have desirable characteristics.

Abstract: According to the present invention, there is provided a wet accelerator for use in the manufacture of a gypsum product, said wet accelerator comprising water, particles of calcium sulphate dihydrate and a stabiliser. Additionally, a method of preparing a wet accelerator and a method of producing a gypsum product are described.