Anyone who hears plaster thinks of mortar, straightening slat, trowel and lots of dirt. In the meantime, plaster has become a generic term that covers everything from the 20 mm lime-cement basic plaster to the 3 mm clay filler compound that can be brought to the wall. With our guide for how to use different types of plaster for walls you will find out exactly what you need to consider when plastering your walls.
We will show you the different types of plastering and what you should pay attention to when plastering the walls. From abrasion to floor and roll plaster, we will show you how it works:
Plastering the wall: Rubbing back
If the basic plaster is applied by trowel and removed with the levelling bar, let it be put on for about 20 to 30 minutes. What follows is rubbing back. You drive with a grater board circularly over the surface to eliminate last bumps, ridges and holes. The art is to find the right time for rubbing. The plaster must not be too dry. This is the basic plaster that becomes a bed for the decorative plasters
Different types of plaster for walls: Decorative plaster
These are pasty masses stirred with water, which can be applied to the wall as an alternative to wallpaper or paint. However, a basic plaster must already be available. Decorative plasters are only between 1 and 3 mm thick, so they cannot compensate for major unevenness. The layer thickness depends on the grain size of the aggregate (usually sand). Synthetic resins are often used as binders, but there are also purely mineral variants. Decorative plasters are basically structured in the surface.
By the way: You should not plaster on old wallpapers!
Plastering the wall: basic plaster
The basic plaster is the masses, which are raised directly on the bare bricks. It is used to protect the supporting masonry from mechanical damage and to create a flat, smooth surface for subsequent wall coverings such as wallpaper, decorative plaster or paint. As a rule, basic plasters contain mineral binders such as cement, lime or gypsum or combinations thereof. Basic plasters are machine-applied and removed by hand, which is less intended for self-made people than for professionals. The layer thickness for floor plasters is between 15 mm and 20 mm.
Different types of plaster for walls: Isoplaster
Its surface and also the isoplaster itself are set so large-pored that it can perfectly absorb the humidity from the room air up to many times its own weight. Thus, it does not settle down as condensation and the mold formation is permanently prevented.
The plaster ground
The right primer is important for any type of decorative plaster. It fulfils three tasks: it compensates for the different suction behavior of the wall as far as possible, it greatly improves the adhesion of the plaster and it covers color differences of the wall. The latter is especially important for the friction plasters, where you can rub the grains on the wall and the wall paint (unless white) can shimmer through the grooves later. Plaster primers are slightly more pasty and coarse-grained than conventional primers to ensure adhesion. In any case, you can save yourself a pre-treatment with a low ground.
Plaster rails serve as an aid to achieve an even cleaning thickness. They are attached to the wall surface to be plastered and to bedcloths (“corner protection strips”,) then the straightening slat is applied and the plaster ingenuation is removed. The corner guards are also used to secure the sensitive outer corners of plastered walls against demolition. Plaster rails are made of different-strong metal or plastic, as “adhesive” are plaster bats, into which you press the rails and align them with lot and flush. The distance between two rails is usually 120 to 150 cm. These rails are not used for decorative plastering because it is too thin.
Different types of plaster for walls: friction plaster
Friction plaster has its name, because after application the contained grains are rubbed with a grater board or the trowel in the plaster. This creates the well-known grooves and channels, which later give the plastered wall the rough surface. Depending on the grain size (1, 2 and 3 mm), the friction structure becomes coarser or finer. You can rub the grains in all directions, but for a uniform structure pattern, the friction direction should be maintained on the entire surface.
Different types of plaster for walls: Roll plaster
This is a misleading term, because the plasters so called can’t be applied with a roll. Roll plasters must also be plastered on the wall in the traditional way with a trowel in 1 to 3 mm thickness. However, it is so fine that you can then easily structure it with a color or structural roll.
In the meantime, however, there is a single “real” roll plaster on the market, the so-called “Easy Putz”. You can actually apply it to the wall with a roll and also structure it.
Different types of plaster for walls: spatula cream
For some time now, so-called spatula creams have been on the market, which are also suitable for decorative design. In composition, they are similar to fillers. You achieve a structure by applying the mass not with a trowel, but with a small spatula. The resulting ridges and unevenness are therefore desirable as a “Mediterranean” effect.
Render or filler compound
Simply put, these are very fine-grained plasters with grain sizes from 0.1 to 0.5 mm. They are used to smooth and equalize an uneven, holey wall. The fine grain also serves to be able to extend the plaster with the smoother virtually to zero and thus leave no approaches on the wall surface. Spatula compounds are unsuitable for decorative design with sponge board, tassel or roll, because they are applied too thinly. For particularly critical substrates or for wet rooms, you also get flexible resin-coated filler compounds.
Different types of plaster for walls: spray-plaster
This is a kind of primer for a basic plaster. Basically, this is nothing more than a very liquid plaster, which is “thrown” against the wall with the trowel. The effect is that the surface of the wall becomes uneven and thus larger, the basic plaster, which is subsequently applied, i.e. finds a larger contact and adhesion surface.
Coating plaster is an almost liquid mass that can be plastered on the wall by a soft brush. According to the consistency, the layer thickness is then only between 0.1 and 0.2 mm. Due to the small thickness, the tassel naturally leaves its traces on the whole surface, which you can use with a little practice for surface design. Even such extremely thin plasters still have the good properties that decorative plasters generally have, especially the moisture-regulating effect on the room air. Although string plasters also find support on old, fixed wallpaper, we always advise to remove old wall coverings completely.
Stretchable metal lattice
The lattice called stretch metal is created by the fact that metal plates provided with offset slots are pulled apart and stretched. This gives it an enormous bending stiffness for the small material thickness. Stretch ingenuities are used as plaster carriers for the basic plasters. They are mainly used over cavities or with changing wall building materials to absorb the tensile stresses that often occur there and thus to plaster the wall without cracking.
A general generic term for all decorative plasters is the structural plaster. The wall is structured in some form after the process has been pulled up. The classic tools for this are roll, tassel and brush, trowel sponge, felt board and grater board.
Important: In this type of plastering, the rolling direction must be maintained on the whole surface!
The term is Italian and means “glossy plaster”. Stucco is an ancient technique with which smooth walls are decoratively plastered. It is originally a pure lime plastering technique, in which three to eight layers are applied to a very smooth base plaster of lime and sand. The grains of the layers become more and more fine. It is important that the smoother is guided at high contact pressure during removal, so that it becomes a smooth, homogeneous and shiny surface. On the top layer you can paint a marble texture almost wet in wet.
Dry plaster includes basic plasters that are not plastered as pasty mass, but as whole, large-format panels. The most famous are the plasterboard, which you add mortar bats on the back and press against the wall. As with the wall, the joints must also be closed and sanded with a joint compound. It is tricky to set the plates in a flow-like manner, which is ensured by the long water scale. The advantage of dry plasters is that they leave no building moisture in the room, immediately offer an absolutely flat surface and can also be managed well by self-makers.
Disadvantage: The layer thickness is slightly larger than with normal basic plaster.
Gerhardt Richter is a writer and a trainer at trade technical colleges, specializing in carpentry, plumbing, mechanics and construction.