- Drywall history
- Drywall – production technology
- Drywall characteristics
- Wall drywall
- Ceiling plasterboard
- Drywall moisture resistant
- Plasterboard fire resistant
- Arched drywall
- Positive characteristics
- Negative characteristics
- Repair of plasterboard surfaces
In this article: how drywall was created; technology for the production of gypsum plasterboards; positive and negative characteristics; how to repair a damaged drywall area without completely replacing the sheet.
Smooth wall surfaces and calculated bends, semi-ovals and volumetric geometric figures – all this is within the power of a rectangular sheet, which, like a sandwich, consists of two outer layers of cardboard and an inner, gypsum one. More than a century ago, the very idea of such a finishing material aroused the laughter of construction contractors, who preferred, albeit complex and overly monumental, but familiar building materials. And yet, drywall, and we are talking about it, has become the main material in the decoration of office and residential construction projects. And the improvements constantly made to its design expand the areas of application, and today the gypsum board is much more complex than 100 years ago..
Gypsum used in this finishing material has been used since ancient times for plastering walls – the Egyptians were the first to use it in this capacity about 6,000 years ago. But the idea to place this natural material between sheets of paper came to the minds of the Americans Augustine Sackett and Fred Kane, the first of whom owned a paper mill. Sackett, like any active businessman, sought to expand his business – bringing the dimensions of gypsum boards to 91×91 cm and thickness to 0.6 cm, in 1884 he received a patent for “Sackett boards” and the machine that produced them. As Augustine Sackett argued a century ago, the sheets and boards invented by him made of layers of paper and gypsum will easily replace classical plaster, among other qualities, they do not form cracks, smooth internal surfaces are achieved in the premises and, immediately after installing such sheets, you can enter and live in such a house. Agree that Sackett accurately described modern drywall!
It should be noted that the “Sacketta board” did not receive much popularity, but the very idea of creating a finishing material of this kind captured the minds of inventors in the field of construction. 24 years after Sackett received a patent, another American inventor, Stephen Kelly, is granted a patent for an improved drywall design. In his invention, the sheet of decoration material is formed by gypsum sandwiched between two sheets of cardboard. A few years later, a gypsum company engineer, Clarence Utsman, finally brought the drywall sheet to its modern look by inventing the closed edge.
The first full-scale production of gypsum plasterboards was opened in England in 1917, and the now widely known German factory of brothers Alfons and Karl Knauf – in 1932. The popular gypsum plaster company Saint-Gobain opened its first gypsum board plant in 1957.
Despite the obvious benefits and convenience of using drywall in construction and finishing works, this material was not in great demand for many years. Drywall was considered a material only for repair work, convenient for partial replacement of worn-out plywood or chipboard boards. Customers did not trust the new material, preferring plaster, tested for centuries. The popularity of drywall came during the Second World War – the cities of Europe were in ruins and had to be restored as soon as possible, in addition, the lack of workers affected, because many construction specialists died in that war.
It was required to reduce the cost of building houses as much as possible, reduce the time for their construction and drywall in this matter turned out to be indispensable.
For example, in the United States, gypsum plasterboards are now widely used, they have completely replaced the once popular plaster – it is much easier to work with drywall. The special appeal of drywall on world construction sites lies not only in simplicity, but also in the refined technology of assembly, putty and painting works – even the tinting of paints has been brought to perfection!
Drywall – production technology
Each large enterprise that produces gypsum plasterboards under its own trademark is equipped with equipment for a five-stage production process: processing and preparation of gypsum stone; continuous supply of gypsum strip with laying between two outer layers of cardboard; cutting drywall sheets; drying; labeling and packaging.
At the first stage, the gypsum stone is crushed, fired, and mineral fibers and fire retardant additives are introduced into its composition. Then the crushed material is combined with water containing a blowing agent.
The second stage is the formation of gypsum plasterboard. The wet gypsum mixture from the mixer enters the conveyor belt, spreading with a layer of a given thickness on cardboard made of special construction paper, on top of the layer of gypsum is covered with another strip of cardboard. The width of the lower underlying cardboard is greater than the width of the gypsum strip and the upper layer of cardboard – as you move along the conveyor, the edges of the lower cardboard layer are rolled up, and the upper layer is glued to the gypsum (a special machine applies the adhesive layer), then all three layers of the future drywall are rolled together.
At the third stage, after the gypsum layer has completely hardened, a continuous strip is cut into plasterboard sheets – this operation is performed by a mechanical guillotine.
The fourth stage – the cut sheets are stacked on pallets and sent to drying chambers, where they are kept for an hour. During drying, moisture evaporates from the gypsum layer, due to which each of the dried gypsum boards gains the necessary strength.
The fifth stage completes the drywall production process. Freshly made slabs are finished to the specified dimensions, stacked on pallets, and the manufacturer’s markings are applied to them. On top of each pallet with fifty sheets of drywall, plastic packaging is pulled and the finished product is sent to the warehouse.
Regardless of brands and manufacturers, drywall is divided into:
Width 1200 mm, length 2000, 2500 or 3000 mm. The thickness of the gypsum plasterboard is 12.5 mm, light gray color of the cardboard with blue markings applied to it. Among other types, this one is the simplest in its composition, since does not contain any special additives and has the minimum necessary physical properties.
Has a width of 1,200 mm, a length of 2,000 or 2,500 mm. The thickness of the plasterboard ceiling sheet is 9.5 mm, the color of the cardboard is similar to the wall one (light gray), the same blue marking. From the name it is clear that this type of gypsum plasterboard is used in ceiling cladding, be it multi-level or curved ceilings, various arches and niches. The only difference between ceiling plasterboard and wall plasterboard is in a smaller thickness, otherwise their properties are identical. Due to the lesser thickness, this type of drywall is cheaper than all others..
Drywall moisture resistant
Width 1,200 mm, length 2,000, 2,500 and 3,000 mm. The thickness of the moisture-resistant plasterboard is 12.5 mm, the cardboard is painted green, marked in blue. It is intended for rooms in which moisture is constantly present, its properties will remain unchanged if the side facing the inside of the room has additional protection against moisture – a layer of primer or waterproofing, a layer of paint or tiled cladding. The composition of the gypsum layer of moisture-resistant gypsum board contains hydrophobic additives, which allow these panels to withstand a high level of humidity.
Plasterboard fire resistant
Width 1,200 mm, length 2,000, 2,500 and 3,000 mm. Has a standard thickness of 12.5 mm, light gray cardboard color, marked with red. It is used for cladding rooms with special fire-prevention requirements, they are sheathed with fireplaces and chimneys. A gypsum layer of drywall of this type contains a greater number of reinforcing additives and fibers, its two cardboard layers, together with reinforcing components, play the role of a double frame that prevents fire. The cardboard frame of drywall of any kind does not support combustion and does not burn, it only charred and, after its complete burnout, only the inner gypsum layer of fire-resistant drywall continues to retain its shape and degree of resistance to combustion temperatures for some time, while all other types of drywall will be destroyed.
Width 1,200 mm and length 3,000 mm, has a thickness of 6.5 mm and a light gray color of the cardboard layer. This type of drywall is designed to build various curved design elements, regardless of the bending radius. The gypsum layer of arched drywall is additionally reinforced with fiberglass, which allows it to be bent without violating the integrity of the sheet. Among other types of drywall, its price is the highest, and this is taking into account that for greater strength of a curved arch, you have to mount an arched drywall in two contacting layers – a sheet of such drywall is very thin.
- light weight. Drywall sheet with an area of 3 m2 depending on thickness, weighs no more than 33 kg;
- environmental safety and lack of toxicity. The components of a drywall sandwich – paper and gypsum – do not emit any harmful substances even when burning;
- flexibility. The drywall sheet is unusually flexible – the bend of dry gypsum board allows you to get an oval shape of a large radius (from one meter to 3), moisture allows you to reduce the bending radius several times;
- ease of installation. It will not be difficult for an experienced builder to install 60 m2 gypsum plasterboards on walls in just 8 working hours;
- humidity regulator function. Gypsum, an intermediate layer of drywall, absorbs up to 15% moisture from the humid atmosphere of the room and returns it back if the air becomes dry;
- allows any type of front finishing, be it painting, gluing wallpaper or tiles;
- irreplaceable when arranging boxes for wiring, building a complex lighting scheme, etc.;
- depending on the type and brand, it can be used to level almost any surface, internal and external, horizontal and vertical.
- low strength, requiring the introduction of additional reinforcing components into the gypsum composition, which increases the cost of drywall;
- low resistance to high levels of humidity (over 75%) in the room, the need for additional protection of gypsum plasterboard surfaces. Damage to the outer waterproofing layer will cause a rapid accumulation of moisture in the gypsum and its swelling;
- on the walls where drywall sheets are installed, it is impossible to place household appliances, pieces of furniture and decor that are heavy. For weighty objects, the installation of mortgages is required, the location of which, after the installation of drywall, cannot be changed otherwise than by destroying part of the surface formed by the drywall;
- drywall boards that have not undergone special treatment, in conditions of constant humidity, will become a habitat for mold.
Repair of plasterboard surfaces
The process of installing gypsum plasterboards itself is described in this article. But what if fragmentary replacement of plasterboard sections is required? Let’s see what we can do here …
So, there is a hole, the area of which is large enough. First of all, you will need to purchase drywall for replacement, its thickness should be the same as drywall from the area being replaced. Having marked the area around the hole, we cut it out so that the edges of the profile frame are exposed on the sides by at least half of their width. The sides of the cut-out area must have a geometrically correct shape, otherwise it will not be possible to insert a new piece of plasterboard into this place. We put the prepared fragment into the hole, fasten it to the profile with countersunk screws, putty the seams and grind it with sandpaper. Next, a layer of primer is applied and painted in two layers. It is worth noting that it is almost impossible to “get” into the color that the walls of the room in which you have just replaced the drywall fragment are already painted – the fresh paint will stand out against the general background.
We figured out the repair of a major damage, but what if a small area is damaged, the area of which does not exceed, for example, 10-15 cm2? A more cunning approach is needed here. Having drawn a rectangle around the perimeter of the damage and drilled holes in the corners, we cut out this area. Now you need to prepare a plasterboard rectangle for replacement – its sides (attention!) Should be 30-40 mm larger than the length and width of the rectangular hole. In the center of the prepared rectangle, you need to drill two holes at a distance of 50-60 mm from each other, into which you need to thread 200 mm of twine of the corresponding diameter, tying the ends together on the front side – you get a ring of twine threaded through the holes in the plasterboard fragment. Now you need to grease the edges of the plasterboard rectangle with glue from the outside (front) side, carefully bring the hole inside, holding the twine ring. We align its position – each side should go over the edges of the cut hole from the inside, then pull the rope towards you and press a piece of drywall to the hole so that the glue seizes. After the glue has completely dried and the plasterboard piece is securely fixed in the hole, cut and remove the twine, putty the recess formed after the repair in the wall to half its depth. After the first layer of putty has hardened, we apply the second – finishing layer, bringing it by the rule to one level with the general plane of the wall. The finishing layer of putty is dry – we rub it with sandpaper, primer, paint in two layers.