Plasterboard

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Plasterboard
Gypsum board stack
Gypsum board stack
origin
raw materials Plaster of paris , cardboard , e.g. T. fibers
Material properties
Thermal conductivity  λ 0.25 W / (m K) (DIN EN 12524)
Specific heat capacity  c 0.96 kJ / (kg K) at 20 ° C
Bulk density ρ 600 to 650 kg / m³
Vapor diffusion resistance  μ 10 (dry), 4 (wet)
commitment
Areas of application Paneling of non-load-bearing walls, suspended ceilings, dry screed

Plasterboard (GK) is a building material made of gypsum , generally in use as a gypsum board (GK) - and gypsum building board (GKB) - with two-sided carton -Bezug, in dry or Akustikbau . The sheets get their flexural strength from the cardboard packaging on both sides, which absorbs the tensile forces.

Gypsum boards (formerly gypsum plasterboard) are often confused with " gypsum wall panels ", but these consist exclusively of stucco, are 60 to 100 mm thick and have tongue and groove all around .

Metal stud frame in drywall

use

Due to the various properties such as low weight, easy and quick processing, high fire resistance and, compared to solid construction, less loss of space due to the construction of thinner walls, plasterboard is mainly used for the production of light, non-load-bearing interior walls , suspended ceilings , sloping roof cladding or screeds .

Due to its low water / moisture resistance, plasterboard should only be used indoors. With appropriate climatic conditions (high humidity) the cardboard layer can form a breeding ground for mold. Frequent condensation on the surface promotes the adherence ( adhesion ) of microorganisms.

Interior finishing and cladding

Plasterboard is used to create non-load-bearing interior walls that can later be easily dismantled or modified. They are also used as so-called dry plaster, in which plasterboards are either glued directly to the raw wall with tie- on binders or mounted on a substructure.

So-called coffers (also “coffers”, previously “ Rabitz boxes ”) are used to clad sanitary installations, electrical cables and other technical equipment . Such disguises are often found in the form of a pretext. Here the panels can be attached to a conventional substructure (see below). Two layers of plasterboard (impregnated if necessary) and a special primer must be used to fix tiles . The installation of maintenance openings for the installation lines is recommended.

Special use

Damp rooms

For damp rooms there are impregnated panels with the designation GKFI or GKBI , which are colored green for easy differentiation.

Gypsum building materials are not stable in permanently damp areas and lose their strength. Alternatively, cement fiber boards are used here. If wall plaster or a tile covering is to be applied, coated hard foam boards ( building boards ), calcium silicate boards , wood wool lightweight boards and stiff, plasterable mineral fiber boards are also suitable .

Soundproofing

A disadvantage of drywall compared to brick walls is their lower stability. Adjacent components such as B. the wooden construction of a loft bed can transmit noises to the plasterboard, which are amplified by the resonance of the flexible panels. For this reason, it is generally advisable to acoustically decouple connections to other components using thin strips of foam, felt or mineral wool.

Protection against airborne noise is achieved with plasterboard walls by the principle of flexible shells. For this, it is necessary that a continuous outer surface ( shell ) of the component is not connected to the second shell at all, or at least not rigidly connected. In the case of a wall, this is achieved, for example, by a double post construction. A suspended ceiling can be attached to the supporting ceiling using spring hangers.
The sound insulation is improved by a layer of a special mineral or soft fiber board , which dampens the air flow in the cavity and thus the sound transmission. Wall openings z. B. sockets, light switches, etc. reduce the sound insulation.
Gypsum boards, in perforated or slotted form, are also used as acoustic ceilings for room sound insulation . The blankets are this with a pad made of absorbent material such. B. acoustic fleece, polyester fleece or mineral wool.

Fire protection

Gypsum contains chemically bound water, which is split off as water vapor when heated up and can therefore cool the adjacent building components for a limited time.

With special plasterboard fire protection panels ( GK - F ) in the system (according to the manufacturer's instructions and the standards mentioned below), fire resistance classes of F90 ​​can be achieved without any problems. Fire-sensitive components underneath, such as steel structures, can also be protected against the effects of fire.

The previous GKF boards (plasterboard fire protection boards, or GKFI for impregnated boards) are referred to as type F (with improved structural cohesion of the core at high temperatures) or type D (with a defined density) according to the new DIN EN 520.

The fire protection standard of DIN 4102-4 specifies the maximum mounting distances for fire protection requirements. The largest possible screw spacing is, for example, 25 cm on the wall and 17 cm on the ceiling.

Radiation protection

Plates clad with lead play a special role . The lamination serves to protect against X-rays and is primarily used in the medical field.

history

Augustine Sackett applied for a patent for the plasterboard in the USA in 1894 , but it was not industrially manufactured until 1910. The name Rigips-Platte is often used as a synonym for plasterboard in German-speaking countries, as the first plasterboard on mainland Europe was produced in Riga ("Rigaer Gips") since 1938 . The name Rigips derived from this is a product and manufacturer name that has meanwhile become a generalized brand name . In 1949, the RIGIPS panel was a completely new product for interior construction for the German construction market. It was initially manufactured by Vereinigte Baustoffwerke Bodenwerder GmbH (now: Saint-Gobain Rigips GmbH ).

In the course of harmonizing national and European standards, the name was changed from plasterboard to plasterboard.

Manufacturer

Production line for plasterboard

processing

If the cardboard layer is cut through with a cutter , the plaster core of the board can easily be broken back over an edge (as sharp as possible). The second layer of cardboard is then also cut through.

Gypsum boards are screwed onto a substructure made of wood or galvanized sheet steel profiles. The joints (only the longitudinal edges of the panel are about 4 cm wide on one side and about 1 mm deep) and the screws that are screwed in sufficiently deep are filled with filler to form a smooth surface. For a positive connection and prevention of cracks, the joints are embedded 6 cm wide overlapping glass fiber fleece strips or grid adhesive tapes for tensile reinforcement . After filling two or three times, the filled areas are sanded with sandpaper or special sanding grids in order to remove any burrs and unevenness. This can be done by hand with a sanding board, but particularly on the ceiling, it is advantageous with a motor-driven sanding plate that is articulated overhead on a rod. Dust protection for breathing and eyes is necessary; wearing gloves reduces the degreasing of the skin by the plaster dust.

Connections to adjacent components are often grouted with permanently elastic acrylic grout, in damp rooms with silicone . The acrylic joints in particular tend to age and then later on in an uncontrolled manner to tear. It is better to stick a separating strip (foam film) to the adjacent component, cut off the protruding separating strip and then fill it with a spatula. Then the grout can be applied. Aluminum corner profiles are filled in at outer corners to protect against damage.

Finally, the mostly gray panels are painted over with paint as desired or prepared with a primer for further processing. Especially before applying wallpaper, you should prime, otherwise you cannot separate the wallpaper from the cardboard coating during a subsequent renovation.

Screed panels are laid in two layers and usually on a leveling fill , glued at the offset joints and then screwed.

Substructure

walls

Today, metal profiles are mostly used as a substructure because, unlike the woods used in the past, they do not deform when exposed to moisture. Consequences such as stress cracks in the filling of the plasterboard and accelerated fire can be avoided. This is especially true for damp rooms or other areas with heavily fluctuating humidity, such as bathrooms, utility rooms, kitchens, garages or house entrances. If no major fluctuations in temperature or humidity are to be expected, rough sawn wood can be preferred to the more expensive metal profiles (which, however, is not permitted according to most of the applicable standards and processing instructions from the manufacturer). Plasterboard can also be placed directly on prepared masonry using plasterboard binder patches or strips.

A substructure made of metal profiles consists vertically of C-shaped and horizontally on the ceiling and floor of U-shaped galvanized sheet steel profiles in widths of 50, 75, 100 (more rarely: 125 and 150) mm. For door openings, special profiles with a higher material thickness, so-called U-stiffening profiles 2.0 mm, are to be used, which are non-positively connected to the so-called raw ceiling and the raw floor via fastening brackets of the same material thickness; alternatively, square timbers can be placed in the C-profiles . In the meantime, new I-shaped wooden profiles are also available, some of which consist of dried wood layers that are partially glued crosswise and which alleviate the problem of deformation. The 50 mm plasterboard framework and double paneling on both sides with 12.5 mm panels results in a wall that is 100 mm thick, and with single paneling it is 75 mm thick. In the case of double planking, the vertical panels with a width of 125 cm are offset by 62.5 cm, the transverse joints are offset by at least 40 cm. The first layer does not necessarily have to be filled (only required for fire protection and noise protection requirements). For sound insulation, a so-called connection seal, usually made of foam with a thickness of approx. 3.0 mm, is glued to the U-profile and the first and last C-profile (i.e. the profiles that are attached to the adjacent components) before the profiles are attached to the structure .

Cover

With suspended ceilings , so-called hangers are common with which the galvanized sheet steel profiles are attached to the ceiling, these are so-called CD profiles and UD profiles in 28 mm. Edge profiles (U-profiles) ensure the connection to the walls. Metal anchors are generally used for the suspenders that are subject to tensile loads , since plastic anchors melt in a fire (fixing the hangers with plastic anchors is normatively not permitted in most European countries, and there is currently no manufacturer who recommends plastic anchors for installing the hangers released - keywords: plasticizer shrinkage and embrittlement) and can cause the ceiling to collapse. The edge profiles have no load-bearing effect, so they can also be attached to fire protection ceilings with plastic dowels. (Attention! Since such a ceiling must be constructed exactly in accordance with the present test certificates, the system provider must always be consulted!) However, it is essential to ensure that the first CD profile is a maximum of 100 mm from the wall remotely mounted.

In addition to suspension with metal profiles, a somewhat more complex and heavier suspension made of rough sawn wood is also possible.

Special feature of the attic extension

In the case of an attic conversion, plasterboard panels less than 20 mm thick should not be attached directly to the wooden rafters from below. It is better to install a substructure made of wood or plasterboard profiles to compensate for and protect against cracking before installation. With this type of installation, it is important not to damage the vapor barrier .

material

Usually either natural gypsum, which is obtained in mining, or REA gypsum are used in the production. This also explains the regional focus of the manufacturing plants in places where natural gypsum occurs or, since German reunification, in the direct vicinity of lignite power plants where FGD gypsum is a waste product. In principle, both materials are equivalent. In practice, however, it has been shown that panels made from REA gypsum are somewhat lighter. Natural plaster is much more suitable for the production of custom-made products, where the panels have to be bent, as they are more resistant to breakage. The reason for this is the arrangement of the individual gypsum crystals, which is more chaotic with natural gypsum than with REA gypsum.

Drywall screws (SBS coarse for wooden substructures, fine for metal substructures) are used for screwing. These screws are phosphated (black surface coating) to avoid chemical reactions with the plaster and the resulting discoloration. For the metal profiles, self-tapping screws are better than just pointed.

For some years now, punches have been used on construction sites to cut or bend standardized sheet steel profiles; they work faster, quieter and cleaner than cut-off machines or hacksaws.

additions

Fibers made of plastic, glass or cellulose are sometimes mixed into the plaster of paris; these plaster of paris fiber boards are more statically loadable and can also be used in damp rooms.

Formats

The following table describes the most common plate formats. In addition, special formats are also available in stores.

Thickness
(mm)
Standard width
(mm)
Standard length
(mm)
9.5
12.5
15.0
18.0
600 to 1250
(special width
1200)
2000 to 4000 *
2000 to 4000 *
2000 to 4000 *
2000 to 4000 *
20.0
25.0
600 + 625 2000 to 3500 *
9.5 400 1500 and 2000
* Lengths in steps of 250 mm each

There is also the “one-man plate” with dimensions of 1500 × 1000 × 10 mm, 2000 × 600 × 12.5 mm and 2600 × 600 × 12.5 mm. However, these then do not fit the standard grid of 62.5 cm for stud walls.

Norms

In Germany u. a. the following standards ( DIN ) must be observed:

  • DIN EN 520 gypsum boards - gypsum board terms, requirements, test methods
  • DIN 18180 plasterboard - types, requirements, testing (edition 2008 applies in Germany)
  • DIN 18181 plasterboard in building construction - basics for processing
  • DIN 18182 accessories for the processing of plasterboard
  • DIN 18183 assembly walls made of plasterboard - execution of metal stud walls
  • DIN 18184 plasterboard composite panels with polystyrene or rigid polyurethane foam as insulation
  • DIN EN 520 replaces DIN 18180 (in coexistence until March 1, 2007)

In Austria, the following standards regulate production, processing and planning in the area of ​​plasterboard:

  • ÖNorm B 3415 gypsum boards and gypsum board systems - rules for planning and processing
  • ÖNorm B 2340 Measures to meet the requirements for the airtightness of the building envelope of wooden and prefabricated wooden houses
  • ÖNorm B 3358 Part 6 Non-load-bearing interior wall systems Part 6: Stud wall systems with plasterboard (plasterboard)
  • ÖNorm B 3410 gypsum boards for drywall systems (plasterboard) types, requirements and tests
  • ÖNorm B 5330 Part 10 Doors Part 10: Steel frames for stud wall systems with plasterboard
  • ÖNorm EN 520 gypsum board terms, requirements and test methods

Web links

Commons : Plasterboard  - collection of images, videos and audio files

Individual evidence

  1. Gips-Datenbuch 2013 (PDF) Bundesverband der Gipsindustrie e. V.
  2. Etex Group bundles gypsum activities under “Siniat” , Euwid, accessed on July 9, 2015