Cement or gypsum plaster: which is better to choose
Various materials are used to level the surfaces. It is necessary to decide which stucco is needed in each particular case - gypsum or cement - based on many parameters: type of base, operating conditions, type of future decorative coating, etc. Understanding this issue is not difficult if you know the characteristics of each plaster.
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Features of cement plaster
Any plaster mixture, regardless of composition, must perform such functions as leveling, such as sealing cracks and joints, improving the heat and sound insulation characteristics of the structure, creating a fireproof layer.
But this or that composition of the material already determines its additional properties, for example, water and frost resistance, creating a strong, smooth or textured surface, etc. Gypsum plaster and cement have much in common, but the differences between them are even greater.
Advantages and disadvantages
If earlier only cement, sand and lime were the constituent components of such plaster, today mixtures with many additives improving its characteristics are produced. It has become lighter, more flexible, it adheres better to the surface being trimmed, and gives fewer cracks during shrinkage.
Therefore, the advantages of modern cement plasters can confidently include the following:
- Mechanical strength. Compared with other coatings, cement mixtures after solidification form on the surface real armor - strong, reliable, resistant to mechanical stress. That is why they are most often used in places with increased operational load.
- Moisture resistance. Due to the high density of the material, it almost does not absorb either water or moisture from the air, reliably protecting the base from its effects. Therefore, the choice: gypsum or cement plaster is simply not worth it when surfaces are to be finished in wet rooms or in the open air.
- High adhesion to mineral substrates - concrete, brick, cinder blocks, etc. With them, the cement plaster not only has a mechanical bond, but also a chemical bond, the materials penetrate each other, so the coating holds firmly and does not break for a long time.
- Affordable price. If you compare not only with gypsum, but also with other types of plasters, cement is cheaper than the rest.
But nothing perfect happens, and this material has its own negative features that must be considered when choosing plaster.
- The main disadvantage is the large weight of the coating, which creates a significant load on both the walls and the foundation.
Tip. The instruction requires preliminary calculations on the permissible load, especially when repairing old foundations. To do this, determine the thickness of the leveling layer.
- Susceptibility to shrinkage and cracking. When the water dries and evaporates, the plaster loses its original volume and becomes cracked. Therefore, it usually requires the application of either an additional layer of plaster, or surface putty.
- Putty is also necessary if walls or ceilings are prepared for painting (see How to prepare for painting the wall: detailed instructions), wallpapering, since the surfaces after cement plaster have a rough, rough texture.
- The complexity and complexity of the application. It is quite difficult to work with such material, not only because of its weight, but also because of poor ductility.
- A large period of solidification. For the plaster layer to gain normal strength and completely get rid of moisture, it takes up to several weeks, which affects the timing of repairs.
Tip. To meet deadlines, purchase ready-made mixtures with special additives that accelerate solidification.
In addition, cement plaster adheres very poorly to wooden, ceramic, plastic, painted surfaces. They must be coated with special primers with abrasive filler, notches, use plaster mesh. But this does not guarantee a high-quality result.
Application area
Given all these features, it is already possible to understand in which cases it is desirable to use cement plaster. This is primarily the alignment of surfaces in unheated rooms (loggias, balconies, porches, utility units, garages) and rooms with high humidity (bathrooms, pools, cellars).
And exterior decoration of facades, socles, fences and other street structures. Especially those that must withstand aggressive atmospheric and mechanical influences.
Note. There is a separation of materials for their intended purpose for internal and external plasters. The latter must necessarily be frost-resistant to withstand many cycles of thawing and freezing without loss of properties.
Features of gypsum plaster
Answering the question, cement or gypsum plaster is better, one cannot but study the composition, properties and characteristics of the latter. Moreover, modern gypsum-based mixtures are also improved by introducing various modifying and plasticizing additives into them.
Advantages and disadvantages
The advantages of this material over the above are many.
These include:
- No shrinkage. When the mixture applied to the surface hardens, cracks do not form on it; therefore, to obtain an even base, one layer is often enough.
- Ability to apply multiple layers. If for leveling it is necessary to eliminate serious level differences, gypsum plaster can be applied an unlimited number of times.
- Light weight. Accordingly - lower consumption, less load on the base, reduced transportation costs.
- Plasticity, ease of application. Due to the fact that the gypsum mortar keeps well on the surface and is smoothed out, even a novice builder can do the finishing himself.
- Vapor permeability. Gypsum has the ability to absorb excess moisture from the air and give it away at low humidity, thereby improving the indoor climate. Such coatings are called “breathe”, without interfering with natural air exchange.
- Heat and sound insulating properties. Experiment yourself, which is more pleasant and warmer to the touch - gypsum plaster or cement.
- Drying speed, for which several days are enough, even when applying a fairly thick layer.
Well, one of the main advantages can be considered the ability to finish with this material almost any surface, including wood, ceramic and polymer, on which cement plaster does not hold.
About the disadvantages:
- Inability to use in conditions of high humidity, in which the gypsum coating swells and begins to fall off the surface.
- Insufficient mechanical strength.
- Higher than cement compositions cost.
The last drawback can be leveled if rough leveling is done with cement plaster, and finishing - with gypsum mixture.
We immediately answer the question of whether it is possible to apply gypsum plaster on cement. It is possible, but the rough plaster must first completely dry, after which it must be treated with a primer for better adhesion of the layers.
Application area
Now it became clear that gypsum plaster is not suitable for external work, and there are some restrictions for internal work. Primarily for use in bathrooms, toilets, kitchens and other “wet” rooms.
This is possible, but only if the composition is characterized by increased moisture resistance or will be applied under the tiles with careful sealing of grout joints.
But for residential premises and for wall decoration with wallpaper or paint, the best material can not be found. Especially if you are going to do this work yourself.
Conclusion
Cement plaster or gypsum is better in one case or another - it depends on the properties of the materials that you are now aware of. It is clear that for finishing the facade of the house, its basement or basement, preference should be given to durable and moisture-resistant cement mortars. And the walls in the nursery or living room are better covered with gypsum - smooth and environmentally friendly.
Universal materials that have all the advantages of both materials also exist, but they have their drawbacks. If you have already made a choice and want to get acquainted with the application technology, watch the video in this article and study the relevant materials on our website.
