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Everyone wants to make their home unique and one of the ways is stucco decorations. Once upon a time, all the elements were made by hand, it cost incredible money and was not available to everyone. Modern technologies make it possible to mass-produce not too complex elements, which has reduced their price. And the stucco work in the interior looks amazing, even in modern interiors, in kitchens and in relatively small rooms.
Types of stucco and materials
Stucco decorations are distinguished by the scope: for decorating buildings and interiors. They are made from different materials. Gypsum, polystyrene and polyurethane are used mainly indoors. This is due to the characteristics of the materials: gypsum is afraid of moisture, polyurethane and expanded polystyrene – direct sunlight. For decoration of buildings, special stucco moldings made of polymer (glass fiber reinforced concrete), sand concrete, fireclay are used. But the price of these decorations and the cost of installation is high.
Is Styrofoam Worth It?
Styrofoam (styrofoam) interior decorations are the most affordable on the market. They are very light and flexible, mounted very simply – with glue. Due to their flexibility, they can be installed on uneven walls. And everything seems to be not bad, but, due to the peculiarities of the material, the surface is slightly grainy, not too dense. Polystyrene stucco molding is generally incomparable with plaster decor – the difference is too visible. But it’s inexpensive.
When using moldings, cornices or other products made of expanded polystyrene, it is better to paint them after installation, otherwise the products will turn yellow after a while. Stucco is painted with water-based paint, but it can be done with any other composition that is compatible with the base.
Styrofoam moldings should be used only if the budget is very limited or if you will soon be doing repairs again. In other cases, it is better to choose between polyurethane and gypsum.
Plaster or polyurethane?
In the interior, usually either polyurethane or gypsum moldings are used. But what to choose? What to give preference? To answer the question, you need to know the advantages and disadvantages of stucco molding from both types of materials.
Gypsum stucco is more diverse, always has a clear pattern, is made from natural material, does not age, does not change performance (if it does not get wet). But it is heavier, more fragile, due to which it is more difficult to install. The downside is the higher cost. Although, if you take high-quality polyurethane stucco, it costs almost the same. But there is still a difference – due to the cost of installation (it is higher for gypsum, since it is more difficult to install).
Polyurethane stucco molding is lightweight, does not break or crumble, is not afraid of dampness, and is easier to install. But she has her own, and a serious, drawback: very often cracks appear at the joints over time. Most of all, it “cracks” if the interior stucco molding was mounted on concrete, brick, wooden walls, on cellular concrete. It is rare to see cracks if the decor is glued to plasterboard walls. This is due to the different response of materials to changes in temperature and moisture. In drywall and polyurethane, they are close, so the joints “do not tear.” Other materials have this problem. It is also worth mentioning that the number of cracks depends on the qualifications of the installers: for some, one crack appears per room or for several rooms, while others have several of them in each room.
Manufacturers of polyurethane stucco moldings advise using special glue for joints, making the connection not in a straight line, but at an angle of 45 °, do not spare expensive glue during installation and apply it to the joints to be glued in excess. The glue that comes out is wiped off, or cut off after drying. These are additional, and labor-intensive operations (especially cutting off dried glue, as well as adjusting the pattern when connecting at an angle), so not all teams use them. Much more often, polyurethane stucco is glued end-to-end, and the glue is applied in a very thin layer, and if it is not enough, the voids are sealed with putty. The strength of such a connection is low, and therefore cracks appear. And in large numbers.
Mounting methods
Stucco molding in the interior of any type is attached to the adhesive, just this composition is different for different materials. The surface to which the stucco elements are glued must be pre-leveled, cleaned of dust, dirt, and dried. Decor elements must be brought into the room, kept for at least a day, but two is better. During this time, the temperature and humidity of the decor and the base will even out.
The adhesive composition is applied both to the stucco element, and to the surface to which it is glued, it is evenly distributed. Then you need to wait 10-20 minutes, then put the decor element in place, align, press well and hold for a while – until the glue grabs. If heavy or bulky elements are mounted, they can be fixed with a few self-tapping screws. Then the fasteners can be removed (or left), the holes can be sealed with putty, sanded after drying.
When stucco is strengthened, irregularities, height differences, and pattern mismatch are very often formed at the joints. These shortcomings are eliminated with the help of fine-grained sandpaper, folded in several layers. This “tool” processes the joint until it matches. Moreover, when polishing polyurethane, a yellow material appears under a layer of white paint (primer) – polyurethane itself. To make the seam invisible, it is better to remove the entire primer layer to the material, then apply putty, sand after drying.
This is a common technology for installing stucco moldings in a room. But there are features of each of the materials, and we will talk about them in more detail.
Features of gluing polyurethane and foam moldings
Polyurethane stucco molding of good quality, with a clear pattern, looks no different from gypsum. Tactilely (by touching), it is easy to determine the difference, but “by eye”, especially under the ceiling, is almost impossible. But polyurethane stucco has two significant drawbacks: cracks that appear at the joints over time and a change in size.
A change in the size of polyurethane stucco for the interior becomes noticeable after six months or more. If for some reason you didn’t glue part of the decor, leaving some details “for later”, in a few months you simply won’t be able to join them. Even if before everything just became and combined. Moreover, the difference will be not only in length, but also in width. “Shrinkage” can be 2-5 mm, depending on the density of the material and the shape / size of the element. Therefore, do not leave imperfections, mount the entire decor at once.
As is already clear, due to the “shrinkage” of polyurethane (and also due to different thermal and thermal expansion of the decor and walls / ceiling), cracks appear at the joints of the elements. To reduce the number of cracks, the elements must be joined at an angle of 45 °. Please note: all joints are made at an angle. Not only in the corners. Even if two straight elements are joined – cornices, skirting boards, moldings – their edges are cut at an angle, increasing the joint area. Thus, the amount of glue increases, the strength of the connection increases, it “breaks” less often.
How to glue plaster molding
Gypsum stucco molding in the interior can be more diverse, it is possible to make individual decorations or assemble a unique pattern from ready-made small fragments. Gypsum decor is also mounted with glue, but its composition is different. There are differences in the method of application: before applying the glue, gypsum fragments are dipped into water for a couple of seconds. Then an adhesive composition is applied to the surface, with a spatula with small teeth evenly distributed over the surface. Further, everything is familiar: we put it in place, press it, leave it to dry.
When installing large fragments of gypsum stucco, notches a couple of millimeters deep are applied to their back surface, after which an adhesive is applied. After installation, massive elements are fixed with self-tapping screws. Their number depends on the mass of the fragment and on your desire. All holes are puttied, after drying they are polished. The joints are also sealed, there are no problems with them.
Stucco in the interior
Generally speaking, stucco products can be divided into two categories: ready-made decor and individually made products. Unique decorations are made only from gypsum – the technology allows, but the cost of such decor is much higher. Therefore, they often combine – where possible they put parts from mass collections, supplementing with individual fragments.
Ready-made decor is of various types: skirting boards, moldings, cornices, columns, semi-columns, pilasters, rosettes, corner elements. These elements are available in polyurethane, foam and gypsum collections. Companies involved in the manufacture of gypsum decor usually make a number of small details that can complement the standard design.
This is not yet an individual production, but it is far from a mass production, especially since you can choose the decoration to your liking by combining different elements.
In a classic interior
Stucco decorations are typical for interiors decorated in the styles of the classical direction. But such rooms should be high and spacious. Then even the most complex decorative designs look organic.
Stucco and modern interior style
The current pace of life dictates its own rules for interior design: everything should be more concise. How, it would seem, is it possible to combine stucco decorations and modern design? It’s even possible. The most common way is to arrange the corner between the wall and the ceiling with a cornice. It can be wide or not very wide, it can be patterned, ornamented, or simply smooth with a few protrusions. This decoration fits into most modern interiors.
If the design is not too ascetic, curly elements, sockets, various decorative panels, cornices and other “things” are quite suitable.