Drywall Specifications and Features of this Material
Entering the building materials store, one can see plasterboard sheets of various grades and various purposes. Inexperienced developers find it difficult to navigate all this diversity. That is why it is necessary to know and understand the technical characteristics of drywall. From this article you will receive a maximum of information about the characteristics and properties of drywall sheets of all grades and purposes.
Content:
- Device and features of drywall sheet
- GCR types and their applications
- GCR categories
- GKL edge types
- Bending strength
- Drywall Flammability
- Dry Temperature Ratio
- Water absorption and softening coefficient
- Dry Conductivity
- About the loads that drywall can withstand
- How much does one square meter of material weigh?
- About sheet thickness
- Symbols of drywall sheets
Device and features of drywall sheet
If repairs are being made somewhere, then it is safe to say that drywall certainly acts as one of the building materials. It is very popular and in demand, as it is great for decorating apartments and houses. This material is inexpensive, completely harmless and non-combustible; it has good soundproofing properties. It can take away excess moisture from the air, and then easily give it away if the air dries. It is pleasant and easy to work with drywall - it is not capricious and simply processed.
Builders especially like the lightness of drywall sheets - this is a big plus both during installation and during transportation. When working with drywall, there is little waste, and garbage collection is much faster. Application in the construction of drywall - this is the so-called "dry construction".
Easy to use material
It is very convenient that a dry tool is not necessary for drywall at all - the minimum that is available in every house is enough. Complex structures from this material can be created due to its special properties. It is enough to wet the drywall sheet, and you can do anything with it. For example, bend it in the form of an arch, build a niche or realize an intricate design project. After drying, the structure will retain its shape. By the way, smooth surfaces are also excellent.
Thanks to the use of drywall, you can significantly reduce the time spent on finishing work. Take, for example, the manufacture of a partition. If you make it from traditional building materials (say, brick), you will have to spend three times as much time. And drywall does not cause allergic reactions, which is also a positive quality.
What are the disadvantages inherent in drywall
Unfortunately, there are properties and characteristics of drywall, which do not add to its advantages. So, this material cannot boast of strength and water resistance. In addition, it is difficult to attach anything to it. It is useless to make holes in the drywall with nails - only dowels with screws can hold a shelf or a picture on themselves. But still, it’s not worth hanging anything particularly heavy, as this can lead to the complete destruction of the wall.
Insufficient water resistance
Insufficient strength
Difficulty mounting on the wall
Drywall device
Nothing complicated - the design matches the name. Gypsum core with additives and cardboard lining on the outside. Special glue holds it firmly. Types of drywall with various properties are available depending on the application.
Types of drywall and their application
Drywall wall (GKL)
Sheets can have a length of 2.3 or 2.5 m. The width of any of them is 1.2 m. This material is 12.5 mm thick, its color is gray. On the cardboard marking is indicated in blue.No special additives to the core are provided; material properties are standard.
Drywall Ceiling
The length of the sheets can be 2 or 2.5 m, and the width is 1.2 m. The thickness is less than that of the wall material - it is 9.5 mm. Light gray cladding cardboard is also marked in blue. This type of gypsum plaster is used for cladding ceilings, as well as for the manufacture of niches, arches and multi-level ceiling structures. The properties are similar to the previous form, differing from it only in thickness. Thanks to this, he, by the way, is the cheapest.
Moisture-resistant drywall (GKLV)
The sheets are 2.3 and 2.5 m long. They have a standard width of 1.2 m. The thickness is the same as that of the wall material (12.5 mm). The facing cardboard is green, the marking is blue. Apply GCR data in rooms with excess humidity, which they easily tolerate. This characteristic of moisture-proof drywall can be improved by additionally covering the walls with waterproofing material. Also in this quality can serve as a paint, primer or layer of tile. This material and the core, and cardboard have a special composition, so they are not afraid of moisture. For this, antifungal impregnation and special additives are used.
Fireproof Drywall (GKLO)
The length of its sheets can be 2, 3 and 2.5 m, and the usual width and thickness are 1.2 m and 12.5 mm. The facing cardboard has a light gray color, and all designations on it are red. Use GCR data where fire safety requirements are high. For example, it may be the cladding of a chimney or fireplace. Such drywall in the core has a large number of fibers and additives intended for reinforcement. This design, reinforced by the outer cardboard lining, it is difficult to overcome the fire. After all, it turns out like a double frame.
Note that the durable cardboard used in any GCR does not burn and does not contribute to combustion. Maximum - he is charred. But the core is able to resist fire only in a fire-resistant type of drywall. In case of fire, it does not collapse and retains its shape.
Moisture-resistant drywall (GKLVO)
Combines the properties of moisture-proof and fire-resistant gypsum plasterboards.
Drywall arch (flexible)
Its light gray sheets have only one length - 3 m. Width, as usual, 1.2 m. But the thickness of the material is small - only 6.5 mm, so basically it is mounted in two layers. Arched drywall make various products of curved shape with different bending radius. They can be bent so easily thanks to fiberglass threads that strengthen the core. However, due to this, the price of the sheets is quite high. And the fact that they have to be put in a double layer further increases costs.
GCR categories
There are two quality categories for rectangular drywall sheets - “A” and “B”. The last of them allows some errors in geometric dimensions. The equipment used is old-style. However, the bulk of manufacturers produce gypsum board only "A" category, so they do not consider it necessary to indicate this in the specifications. But you need to know about it.
GKL edge types
The standard width of the sheets is 1.2 m. They are made in accordance with GOST 6266-97: inside the two layers of strong cardboard there is a hardened mass of gypsum with special additives for reinforcement. The lateral, longitudinal sides of the sheet are wrapped in cardboard.
There are several types of edges used in the production of drywall. This is done for more convenient processing of joints between sheets. It is worth remembering that all the ends of the GCR are always only rectangular. If there is a need to join precisely these sides (short), then they need to be beveled about a third.
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PC (straight edge) is used when joints do not need to be repaired. |
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Criminal Code (edge with thinning) is needed if a reinforcing tape and putty are used for sealing. |
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PLC (semicircular face edge) is used when working with putty and in the absence of reinforcing tape. |
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PLUK (semicircular face edge with thinning) can be used when working with putty and with reinforcing tape, and without this tape. |
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ZK (rounded edge) is used if the joints are to be repaired with plaster. |
Bending strength
This characteristic is determined by the minimum load at which the drywall sheet is able to collapse. Calculation is carried out in kilograms. To check, take a sample 40 cm wide and test it on supports, the distance between which is 40 times greater than the thickness of the sheet.
- Minimum load for drywall sheet 10 mm thick. is 15 kg.
- The minimum load for drywall sheet with a thickness of 11 - 18 mm. is 18 kg.
Drywall Flammability
Drywall is not a combustible material; moreover, it can withstand fire for a long time. As a matter of fact, any gypsum-containing materials can boast of such qualities.
- GOST 30244 defines combustibility - it is for gypsum plasterboard G1;
- GOST 30402 defines flammability; in drywall it is B2;
- GOST 12.1.044 determines the ability to form smoke, according to this indicator drywall refers to the group - D1;
- GOST 12.1.044 determines toxicity; drywall belongs to the group - T1.
In case of fire, the characteristics of fire-resistant drywall allow it to withstand the fire. The gypsum itself cannot burn, and after the destruction of the cardboard, the core simply crumbles. To increase fire resistance, partitions are made of two sheets of drywall. So cardboard between two sheets is able to resist fire for a longer time.
Dry Temperature Ratio
All the negative temperatures that are possible in nature, gypsum boards perfectly withstand. Neither their destruction nor fatal changes in physical properties occur. As soon as the temperature rises, the sheet is completely restored. GCRs feel best at room temperature - after all, they were created for internal work.
Water absorption and softening coefficient
For grades of drywall with moisture resistance (including those which, in addition, are fire resistant), moisture absorption of not more than 10 percent is permissible. Drywall also has one more important parameter, the softening coefficient Kp, which is calculated by dividing the tensile strength in a water-saturated state (Rн) by the dry strength (Rс).
If we talk about sheets of ordinary drywall, then their strength with strong moisture is significantly reduced. Such materials are sold quite a lot, and they all have a small softening coefficient of approximately 0.8. But the GCR has a slightly different value for this parameter - 0.45. This means that after wetting, the strength of this material will greatly decrease.
Dry Conductivity
To begin with, it should be noted that drywall retains heat quite well. The thermal conductivity coefficient of drywall is from 0.22 to 0.35 W / (m × K). This is not bad - because during the repair, you can immediately make the walls even, and slightly improve their thermal insulation. It should be noted that this method of thermal insulation of walls is inexpensive, fast and effective. And if you make a gap of 3 to 10 mm, an additional air layer will appear, helping to even better save heat.
To achieve a good result in thermal conductivity, various heaters are laid in the cavity between the insulated wall and drywall. This can be, for example, mineral wool or ordinary polystyrene. The farther we move the drywall plate from the wall, the thicker you can make an additional thermal insulation layer.
About the loads that drywall can withstand
If we want to hang a shelf or a cabinet on a drywall, we must remember that the load should not exceed 30 kg per square meter.
How much does one square meter of material weigh?
Sheets of the type GKLV and GKL weigh no more than 1 s (kilograms per square meter). Fire-resistant sheets - not less than 0.8 and not more than 1.06 s (kilograms per square meter).
About sheet thickness
Drywall, which is sold in stores and in the market, most often can be 6, 9, 12 mm thick.The thinnest GCRs, having a thickness of 6 mm, are used for the "wet method" - they make complex curved products (arches, design structures, niches) from them. A thickness of 9 mm is well suited for bending sheets in the "dry way" and creating the same arches - experienced craftsmen usually do this. Ceilings are also made from nine-millimeter gypsum plasterboards in order to reduce the weight of the structure. The thickest sheets are used for wall cladding and creating partitions. Other sizes are extremely rare on sale, and therefore they, as a rule, are not of interest to the average buyer.
Symbols of drywall sheets
To decrypt what is written on the sheet, recognizing the characteristics of drywall, as follows:
- Letter designation of sheet type;
- information about which group the sheet belongs to;
- longitudinal edge information;
- length, width and thickness in millimeters;
- manufacturing standard - GOST 6266-97.
For example, take the drywall sheet of group “A” from the company KNAUF. Its length is 2500 mm, the width is standard, the semicircular edge, thickness is 9 mm.
On the sheet you can see the following markings:
GKL - A - PC - 9 × 1200 × 2500 GOST 6266-97.
or
GKL - PC - 9 × 1200 × 2500 GOST 6266-97.
