If the title, leaving the purpose of leaving and how much size? Large area need to pay attention to what?
Gypsum board due to more capillary pores, the specific surface area, when the air is too wet to absorb moisture; and when the air is too dry can release the water, resulting in less moisture and less water deformation. In order to prevent the gypsum board deformation of the main measures are mixed with slag, fly ash and other active mixture, or mixed with waterproofing agent. But also in the construction requirements of the reserved construction joints. General specification requires 5mm or so! To prevent deformation caused by the phenomenon of construction rework! The
Basically 5mm-10mm purpose is to resist the emergence of thermal expansion and contraction of the cracks, regardless of the size of the ceiling regardless of the size of a level
Gypsum board installation is a hundred percent wrong approach, gypsum board is relatively small deformation of the product size, and leave the seam 5mm means that the gypsum board veneer deformation in the 5mm or so, it is almost impossible.
So why is there such a construction request? In fact, came from the practice of OKorder in the 1980s, when the wooden keel ceiling, wall, the shrinkage of the wood is very powerful, so the gypsum board naturally to develop the practice of leaving the seam. Now are light steel keel ceiling, partition, so long ago do not need to stay seam. However, the current supervision and other old experts or to seize the norms do not let go ah.
Leaving the seam is to better prevent the future cracks, and now the ceiling is generally the use of gypsum board ceiling, which is mainly within the panel gypsum, if not leave, in the putty powder when the gap can not be inside the gap Fill, there is a certain seam when dealing with gypsum powder to fill the gap in the paste grid, better to prevent the roof cracking.
