Plasterwork

As a plaster or plaster is called a covering of plaster, which is applied to masonry or concrete surfaces on exterior and interior walls and ceilings.

Depending on use, the plaster meets various purposes, such as producing a smooth substrate for coating, tile, painting or wallpapering, regulating the room humidity in interior plasters, insulation and water repellency in external rendering and the production of aesthetic appearance.

Word origin

Plaster was made ​​clean from the verb in the 17th and 18th centuries. The brush used since the 15th century, originally meant " the slug ( uncleanness, Schmutzklümpchen, lumps ) Remove " (the word is to the effect obtained approximately in the slug ). Hence the two meanings developed " clean, clean " and " embellish, adorn ". On the importance of cleaning build on today's composites such as house cleaning and spring cleaning. The importance of adornment can be found in old terms such as headdress or milliner, both terms stuck in the plaster " walls with mortar throwing ".

This cleaning means in the strict sense only the aspect of clean and ornamental Endbewurfs falls ( to the allfällig a color job is still attached ), the aspect of the leveling layer for tiling and wallpapering under the term mortar (Latin mortarius " the finely ground in a mortar "). Therefore, one generally speaks expressly of plaster when you mean the material and plaster / plaster when you mean the Endbewurf.

Types of plaster

Different types of plaster are on the materials used, typically on the binder ( lime plaster, cement plaster, cement plaster, gypsum plaster, clay plaster, silicate plaster and organic or synthetic resin plaster ), to the place of mortar production (factory - dry mortar, construction mortar), differentiated according to the preparation (hand cleaning, machine cleaning ), after surface treatment ( sgraffito, textured plaster, trowel throw plaster, trowel stroke plaster), according to the function ( insulating plaster, acoustic plaster, Restoration, MagnetStucco ) or after the application thickness.

Plaster coat

Traditional thick film plasters are used in which the material application is usually more than the strength of the maximum grain size of the aggregate. An exception are rough finishing coats whose maximum particle size of up to 8 mm (rarely up to 16 mm ) through the relatively thin cranking the mortar or the later partially made ​​washing out the binder and fine grain (similar to exposed aggregate concrete ) emerges decorative from the surface.

Thin plasters usually contain resins and other additives, which make by delaying dehydration, increasing the binding force and improve the processing properties of an application thickness of 3 mm, for example. Fillers can even partially undressed " to zero ". Thin plasters are often used for rehabilitation of old plaster surfaces and as final decorative layer of thermal insulation composite system. Often a reinforcement is incorporated in the form of a fiber fabric in order to avoid cracks.

Rough cast ( adhesion promoter ): Thin is rührter rough cast is like a net with a trowel or brush on a little absorbent or smooth surfaces ( eg concrete), it does not obscure, fired up. On highly absorbent (eg, low fired brick, plaster or clay) or uneven surfaces (different materials ) of the spray plaster is cranked all over.

Bonding: Instead of rough cast concrete surfaces to be generally organic bonding agents, eg used for pretreatment for gypsum plaster or mineral bonding agents for surface preparation of lime - cement plasters.

Flush ( base coat ): On normal absorbent substrates, the flush can be applied in thicknesses from 1 to 3 cm ( in special cases up to 10 cm ) directly on the ground. The base coat is to compensate for any unevenness. Varies required to compensate for film thickness by more than 5-10 mm, but a previous filling in the low areas is usually necessary because the plaster surface otherwise no longer be peeled off evenly. If they do not occur bundled to individual pipes and cables can, however typically often embed the flush. The base coat acts as a carrier for finishing coats ( plasters ). Traditional base coats contain as binder mostly different limestones (often with interests in cement) or gypsum. They are used indoors partly as a background for wallpaper or paint. Plasters with a higher proportion of cement to be used as base plaster or in damp areas (such as basements and bathrooms ) and as a base layer of hard wall coverings (natural stone, tiles).

Monomass: With Monomass the final plaster coat of plaster system in exterior and interior area is called. He can as thin plaster ( organically bound plaster, layer thickness = maximum grain starch) or thick layer plaster ( mainly mineral bound plaster, layer thickness> maximum aggregate size ) are executed. Mineral-bonded finishing coats are building physics cheaper, but need for a uniform appearance and the weather protection are usually a leveling and smoothing.

Further classifications:

By Material

• Lime plaster: Is usually used as a cleaner for historic buildings, due to its low strength and better voltage recording. Needed to process the experienced and skilled craftsmen and longer drying times.

• Clay plaster: clay plaster is used in Central European climate primarily indoors.

• Cement plaster: Classic plaster for interior and exterior. Frequently as Kalkzementleichtputz ( includes smallest polystyrene beads or mineral supplements, such as pumice or expanded glass ) used on facades and in damp conditions.

• Gypsum plaster, gypsum -lime plaster or gypsum -lime- cement plaster: Smoothed or verriebener plaster for indoor use. Suitable for further coating with wallpaper. It may be used in damp rooms to load class W3 ( ie domestic kitchens and bathrooms ) are used, but not similar in commercial wet rooms, garages ( Stress class W4).

Outside gipshaltiger plaster is only exceptionally used in the monument restoration for adjusting historical plaster mixtures.

• Cotton cleaning: wall and ceiling coating for interiors, consisting of cotton fibers and various fillers and functional materials. As the binder acts cellulose. Cotton cleaning and other natural fiber coatings are usually used as a finishing coat instead of a wallpaper or a rubbing or scraping plaster.

After surface design

• Roughcast: Through traditional and often regionally differentiated treatment during or after the application of different surface effects. The Rauputzen include, for example Rapp plaster, sgraffito, Graupenputz, Knott litter etc.

• The surface structure of brushing is after application by processing with the trowel, the trowel, the brush or other tools designed (eg trowel plaster line ).

• Reibeputz: Depending on the grain size of the aggregate, the surface of the plaster is smoothed in the treatment with the trowel or structured ( eg Munich rough plaster, plaster worm )

• Felt plaster: The plaster is leveled with a felt float and rubbed, giving it an almost smooth surface.

The rubbing and felts of external rendering should be avoided as it leads to the enrichment of the binder on the surface and thus to its hardening and susceptibility to cracking. For the same reason, interior plaster should not be handled excessively long with grater or felt float.

• Straight flush: Using trowel, flat iron or polished stones ( Tadelakt ), the surface of slow-setting lime or clay plasters one or more times smoothed ( stucco lustro ). Modern resin bonded smooth plasters are also spackled and sanded. Skim coats in the outdoor area is susceptible to cracking, often little moisture dispersant and appears in raking light often uneven.

• Schlämmputz and weld cleaning is typically used to clean up or revision of cracked old plaster or as a thin ( steinsichtiger ) coating on natural stone or brick walls.

• In medieval buildings such as castles often the Rasa - Pietra - plaster was applied. ( = Elapsed stone). In this technique, the mortar between the bricks has elapsed, until the wall forming an almost flat surface, the head block but remained uncovered. Sometimes were also drawn with the trowel joints in the wet mortar to obtain a joint pattern ( "Joint Line" ).

By Function

• Insulating plaster: Usually only used in the renovation of old buildings, since much better insulation values ​​are achieved by a thermal insulation system on the outside of the wall. With the use of internal insulation of the exterior walls, the required values ​​of the Energy Saving Ordinance ( U- values ​​<0.07 ) can also be difficult to achieve because of the insulating plaster thicknesses of> would have to have 10 cm. However, can be eliminated by a Innendämmputz mold problems, the Wiederaufheizbarkeit little-used areas is accelerated.

However, the disadvantage of the conventional cementitious Innendämmputzes is a lack of diffusion ( water may be through the wall poorly absorbed and emitted again ). In case of insufficient ventilation mold growth can be even faster. In addition, the cold spot is shifted inward ( Frost penetrates deeper through the outer wall, since the heating can not heat the wall ), with the result that more work will durchfrostet wall and may develop cracks ( by water frozen ). For the so-called condensation Innendämmputz plasters were developed with very large capillary volume in recent years, which have solved the mold problem.

Duration Damp masonry usually leads to salt efflorescence. Soft plasters, such as Luftkalkputze, are hereby tender.

• Pure Luftkalkputze be used as a sacrificial plasters, which are used especially in conservation to receive the above-mentioned salts damage the building over a given period of time, after which they are cut off and replaced. This is especially useful for restoration measures after floods or generally after draining a building.
• In the common base plasters are predominantly cementitious plasters barrier, which only allow the water vapor to pass, but not the upcoming liquid water. Thus, the salts crystallize often at the interface between masonry and plaster to solve the plinth plaster over a large area from.
• Restoration are highly hydrophobic, provided with special air -entraining agents, lime-cement plasters, their special pore structure for the evaporation of water leads within the plaster layer, whereby the remaining damage the building salts are incorporated in the plaster structure. Visible structural damage caused by moisture / salts are thereby minimized as long as, until the pores are filled with salt. One criticism is that the cement content itself may contribute to the salt load of the masonry. Restoration - WTA are by the Scientific and Technical Association for Building Preservation and Conservation certified products. The certification as well as the application of Restoration - WTA is governed by the corresponding WTA leaflets.
• See also: Hydroment

Materials

Plasters can be made of many materials. Traditionally, they consist of binders, aggregates and water. Quartz sand, gravel, minerals and crushed brick are mineral aggregates. Supplements such as straw, animal hair, fiber and flour, inter alia, are often added for reinforcement, structure formation or color and lightweight aggregates such as vermiculite, foamed glass granulate, cork, expanded clay, EPS, inter alia, to reduce the thermal conductivity. So-called compensation and additives such as plastics regulate the technical characteristics.

For the distinction of brushing after the material is usually a distinction according to the binder, as this has a decisive influence on the properties and the use of the plaster.

The binders are distinguished as follows: mineral -based plaster and organic plasters. Mineral plasters are inorganic binders, particularly common lime, cement, clay or silicate (water glass), especially in traditional and / or ecological construction methods. Often lime and cement are mixed in order to improve the processing properties. Organically bound plasters have organic binder, plaster ( interior plaster ) so-called synthetic resins (dispersion), if necessary, with shares of silicone resin, acrylates and Others

Processing

Plaster can be applied by machine or by hand. Depending on the surface of the finished plaster is called rubbing, structure or spreading plaster. Different grain size of the aggregates and by different treatment of the fresh plaster ( wall ironing, Trowel strokes, scraping, sweeping, ... ) produce different effects.

There is usually a cleaning system consisting of several layers. Mineral plasters are fired up usually in a rather thick layer (about 1.5 cm) and can be used as an alignment layer for irregularities in the surface. Many plastic plasters, which form the outer conclusion of a thermal insulation system, on the other hand reared very thin.

To prevent the formation of cracks in the plaster and to increase its resistance, a reinforcement ( reinforcement) may be useful. For this purpose, incorporated, for example, glass fiber cloth in the plaster layer.

Function

Plaster used to produce a pleasant appearance of visible surfaces, to protect these surfaces from harmful influences and as a basis for protective and decorative coatings, such as tiles or wallpaper. He also met physical building functions: control of humidity by absorbing and releasing water, thermal insulation, protection of components against water (for external plaster ), sealing of wasserberührtem masonry eg in swimming pools or clarifiers.

Some plasters have a special aesthetic function. For instance, the fresco, in which the still wet plaster is painted. The color penetrates deeper into the substrate than with other techniques of painting, resulting in extra long durability of the artworks. Even the stucco marble or Stuckolustro allows elaborate design variants. This is created by the addition of certain additives and pigments, followed by polishing and waxing the top layer of plaster a marble-like surface.

A particular feature of building physics meet, for example, thermal insulation plaster systems, which usually consist of a thicker insulating layer and a thin top coat, acoustic plaster, which absorb a great deal of sound, or Restoration, which are suitable for durchfeuchtetes, salty masonry.

Modern lightweight plasters or ultra - lightweight plasters were developed in order to plaster the more lightweight and highly insulating wall formers.

Executive Craftsman

The craftsman who processed the plaster, the plasterer, plasterers, or cleaner, regionally also daubed, masons, Rabitzer, Plisterer or Ibser. The plastering of top coatings such as noise or roll trim is now also performed by the painter.

Important rules

VOB Construction Contract procedures for building works - Part C: General technical specifications in construction contracts (ATV)

• DIN 18345 external thermal insulation composite systems.
• DIN 18350: plaster and stucco
• DIN EN 13914 -1 -2: plaster and stucco
• DIN V 18550:2005-04 plaster and plaster systems - Design