New types of building materials are systematically appearing on the market of materials for construction and repair, the names of which sound incomprehensible to ordinary citizens in terms of their technical characteristics and possibilities for practical use.
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What is gypsum plaster and where is it used?
The relevance and convenience of constructing gypsum partitions when it is necessary to divide a large interior space of an apartment, especially in new buildings, does not raise questions among professionals, but apartment owners who do not often undertake repairs or even redevelopment of their apartments, have a reasonable question: “Gypsum partitions - what are they and where are they used?”
Gypsum plasterboard slabs (essentially slabs cast from gypsum in a certain form) should not be identified with gypsum and alabaster slabs, although the main component in all these types of blocks is natural gypsum. The specified slab materials differ in the percentage composition of the components, and accordingly, in technical characteristics.
The gypsum composition includes:
- gypsum is the main and binding component, a natural, non-flammable material, does not emit odor, is non-allergenic, does not conduct electricity, does not mold, and is not destroyed by fungi and insects;
- mineral additives that increase the density and strength of the structure, the workability of the finished product, since natural gypsum easily turns into powder when working with it;
- hydrophobic additives, the purpose of which is to preserve the internal structure of the product from prolonged exposure to moisture and destruction.
Production and design features of gypsum plaster
The manufacturing technology, composition, dimensions, characteristics, control methods and acceptance of gypsum plaster products are regulated by GOST 6428-83. Products obtained according to the technological documentation established by the standard allow for quick, easy, inexpensive, structurally reliable high-quality, environmentally friendly repair of a room wall or its redevelopment with the construction of durable, lightweight, fire-resistant partitions. The specified standard was adopted in 1983. At present, manufacturers of gypsum plaster blocks and slabs, along with GOST, are developing TU, which allow for the manufacture of products with more advanced consumer sizes and characteristics.
The state standard establishes 2 types of gypsum boards:
- With grooves on the edges for joining two blocks, filled with mortar after joining.
Drawing of grooved gypsum plasterboards, which are no longer in production - With grooves and ridges of rectangular or trapezoidal shape. Such a butt joint is defined by GOST as a product of the highest quality. The shape of the ridge does not affect the quality and strength of the mortar joint.
Gypsum blocks with rectangular and trapezoidal groove/ridge shape
The standard sets maximum deviations from the accuracy of the dimensions of grooves and ridges, and for the connection of the 2nd option they are more stringent than for the 1st option. The price of the first category products is less than the price of the highest category blocks.
The current standard provides for the following slab sizes according to length and height:
- 600 x 300 mm;
- 667 x 500 mm;
- 800 x 400 mm;
- 900 x 300 mm.
Gypsum plasterboards are distinguished by:
- By structure:
- hollow blocks with a thickness of 80-100 mm, which, compared to hollow blocks, have a lower weight and better noise and heat insulation qualities;
Hollow moisture-resistant tongue and groove slabs - hollow, 35-40 mm thick, have greater strength and reliability.
Tongue and groove monolithic hollow gypsum slabs
- By degree of moisture absorption:
- normal (25-33%) - for dry rooms with normal humidity levels;
Conventional gypsum boards are used to construct partitions in rooms with normal humidity. - moisture-resistant (less than 5%) - for rooms with humidity over 60% (Portland cement is added to their composition, and they are painted green to distinguish them).
Moisture-resistant gypsum boards are used to construct partitions in rooms with high humidity
Choosing gypsum partitions – what to pay attention to
The practice of using gypsum blocks has shown that one should choose:
- for walls in the kitchen and bathroom – moisture-resistant (hydrophobic) blocks;
- if you have a wooden floor - hollow blocks, for a monolithic floor any type will do;
- for interior partitions - both types: hollow and hollow, taking into account that with high ceilings it is better to place stronger hollow blocks below.
Preparing for installation
As mentioned above, gypsum partitions are easy and simple to install due to their convenient dimensions and the presence of strong butt joints. Electric cables can be run inside and outside the partitions, and thin pipelines can be run through them.
It is also worth noting the perfect geometry of the slabs, the smooth surface that does not require subsequent plastering of the wall (only puttying of the seams).
Gypsum plaster is easily sawed using a hand or electric saw.
What needs to be done before installation begins
- Draw up a diagram of the partition and determine its dimensions (professionals do not recommend installing a partition with a wall length of more than 6 m and a height of more than 3.5 m), taking into account that it will not be possible to install a rounded or curvilinear structure.
- Select the type of blocks, the required quantity, and the assembly glue to fasten the blocks together.
- Prepare the necessary tools for cutting, chasing, cleaning seams, measuring the floor level, since the blocks must be installed on a perfectly flat base, and prepare other measuring devices.
- If necessary, prepare materials such as dry cement mixture for leveling the floor and underlay.
- Make markings on the floor for the doorway if it is planned in the partition.
- Bring the blocks into the room before installation for several hours to equalize the temperature inside and outside the block.
Repair of damaged slab
- Remove dirt and dust formed during cleaning from the damaged area.
- The cleaned area and the area next to it (for a few cm) should be treated with a deep penetration primer to stabilize the structure of the gypsum.
- Prepare a mixture of gypsum and PVA.
- Wet the damaged area with water, repair the damage with a plaster solution, and to strengthen it, apply a nylon mesh to the wet area and press it into the repair mixture so that it does not come out after drying.
- After drying, clean the surface.
- Restore decorative coating.
