Features of gypsum plasters and rules for their application

Gypsum plasters are widely used to create durable, smooth surfaces for ceilings and walls. Because of their reputation for being simple to work with, they are favored by both professionals and do-it-yourselfers.

Depending on the surface and desired finish, these plasters can be applied in different thicknesses and are adaptable enough for a variety of interior spaces. They also dry quickly, so you won’t have to wait a long time to proceed to the next phase of your project.

When applying gypsum plasters, it’s crucial to adhere to certain guidelines for the best results. A perfect, long-lasting finish requires careful surface preparation, mixing, and application methods.

Gypsum plasters are a popular option for both professionals and do-it-yourselfers because of their smooth finish, short setting time, and ease of use. To achieve a perfect finish when applying gypsum plaster, it’s crucial to properly prepare the surface, mix the plaster to the proper consistency, and apply the plaster in even layers. This post will walk you through the essential characteristics of gypsum plasters and offer helpful advice to guarantee a good application.

What gypsum plaster consists of

Gypsum powder is the primary component of this material and holds everything else together. It is formed from a naturally occurring mineral that has been ground and heated for an extended period of time. Plasters are made from gypsum of different fractions; the higher the quality of the surface treated, the smaller the mineral’s grain size.

Furthermore, gypsum plaster is composed of different polymer additives and a light, fine-grained filler that can be synthetic or natural in origin. The filler grains’ size and shape have an impact on how the future surface will look. Additionally, fillers greatly lower the amount of plaster needed and increase the surface’s durability. Polymer components improve the material’s adhesion to different bases and elasticity.

Paper bags with different weights are used to carry a powdered mixture of universal gypsum plaster. To prepare it, water is needed. Depending on the objectives, you can alter the plaster’s fat content by varying the amount of liquid. Make a liquid solution that will spread easily over the wall in order to decorate the finished coating or perform final leveling on a pre-prepared surface. Make a denser mixture for rough leveling, pothole sealing, and crack sealing.

General information

The typical technical features of gypsum plaster are listed below; these could change based on the supplier and the kind of material used:

1. Operating temperature range – +5…+30 °С.
2. Maximum layer thickness without reinforcing mesh – 5 cm.
3. Dilution proportions: dry gypsum plaster -1 part, water – 0.5 parts.
4. Consumption of this material per square meter – 8 kg.
5. Material setting time – 1 hour.
6. Complete surface drying – 3 hours.
7. Strength gain time – 7 days.
8. Thermal conductivity of gypsum mixtures – 0.23 W/m*C.

Advantages and disadvantages of plaster

This material’s advantageous qualities have led to its widespread use:

• Gypsum plaster mixture consists of 95-97% natural materials that do not emit toxic substances when heated or wet.
• After drying, a perfectly smooth coating of a pleasant shade is obtained, so further finishing with wallpaper, tiles or paint is optional.
• High adhesion to almost all surfaces, due to which the material does not lag behind the wall.
• The relatively small mass makes working with the material convenient, and also allows finishing ceilings.
• The plasticity of the solution allows it to be easily stretched over the surface, which significantly speeds up and facilitates the work.
• Gypsum-based plaster does not shrink, so it does not crack.
• Vapor permeability provides high-quality ventilation of the wall, due to which water will not accumulate under the layer of material.
• Gypsum does not support combustion and does not burn, therefore it is an absolutely fireproof substance.

There are a few drawbacks as well:

• Low moisture resistance, due to which the scope of application of the material is limited to dry rooms.
• You cannot cover surfaces with metal parts with gypsum plaster, since the material will constantly absorb moisture, which will lead to corrosion.
• High price, in comparison with other types of plaster.
• Low mechanical strength.

What does the consumption depend on

The thickness of the layer and the levelness of the walls have a major impact on how much gypsum plaster is used per square meter. A pre-prepared or simply non-curved surface (slope of no more than 5 mm) will require about 300 grams of gypsum plaster with a 1 mm layer thickness.

To calculate the plaster, you can use the following example. Let"s say there is a section of the wall with an area of ​​1 square meter with a slope of 3 cm. First, you need to weigh the surface at three points. In the first, the slope is 0, in the second – 1.5 cm, in the last – 3 cm. We sum up the obtained values, we get 4.5 cm, divide by the number of values ​​3, we get 1.5 cm – average slope. This is the thickness of the minimum layer for leveling. After this, we multiply the 15 mm layer by 300 grams of the solution required for a 1 mm layer, we get 4.5 kg per square meter. Next, you need to take into account that there will be a decorative layer about 3 mm thick, for it you need another 0.9 kg. As a result 5.4 kg, add 10% for stock and round up to a higher number. As a result, for this wall you will need 6 kg of facade gypsum plaster or universal mixture.

Independent preparation of the solution

Three primary categories of materials are available for home production:

1. With wood sawdust. 4 parts gypsum, 1 part wood sawdust, 1 tile adhesive.
2. Gypsum-chalk solution. 1 part gypsum, 3 parts crushed ground chalk, 5% wood glue from the total mass of the mixture.
3. Lime-gypsum solution. 1 part gypsum, 1 part lime dough.

The following are the guidelines for getting ready:

• Measure out portions of components in special containers.
• Mix dry components.
• Add a little water and mix with a construction mixer or a drill with an attachment.
• Leave to infuse for 3 minutes, then mix again.

Note: Both homemade and store-bought mixtures made from dry ingredients can be prepared according to these instructions. To make lime-gypsum mortar, gypsum is first soaked in water, then mixed with the lime dough.

Preparing walls for plastering

Prior to applying gypsum compounds for rough finishing on walls, the following actions must be completed:

1. Remove old coating and clean the surface from grease stains, dust, wallpaper and paint residues.
2. Tap the surface with a hammer to identify weak wall fragments and remove them.
3. Fill cracks, potholes and chips with polyurethane foam or cement mortar.
4. Prime the walls 2 times with an interval of 4 hours.

Vital! Because the applied gypsum mixture tends to fall off quickly due to its large thickness, installing a reinforcing mesh is necessary.

• First of all, markings are applied to the wall – dots every 40 cm.
• Drill holes in the marked places and install dowels.
• Using metal scissors, cut the mesh into fragments of the required area and shape.
• Apply the product to the wall and fix it with screws.

It is necessary to reinforce the mesh with wire if it is not installed tightly or vibrates when touched. The wire should be threaded through the cells in the Z-shaped pattern.

Procedure for applying gypsum plaster

The prepared solution should be applied in a single layer that is no thicker than 5 cm in the absence of a mesh or 8 cm in the presence of one. After gathering the solution on a trowel or spatula and moving it to the surface, the solution is stretched using the same tool. Next, you must level the material using a rule. This is accomplished by applying the tool to the wall’s bottom and moving it upward in zigzag motions.

You should know this! If the gypsum plaster is still on the rule’s blade, it cannot be used because it dries so quickly.

It is required to apply a trapezoidal rule to the surface an hour after the solution has been applied to the entire wall. Next, using a wide spatula, all imperfections are puttied and smoothed out. Using a spatula, you can also remove any remnants of the rule. In about 30 minutes, the next procedure should begin. You will have to wait a little longer, though, if you can press a finger through the surface.

The steps are as follows:

• The surface is generously moistened with water.
• Wait until the wall becomes matte.
• Take a sponge float, press it against the wall and make circular movements.
• Smooth the entire coating with a wide spatula.
• Wait 5-7 hours and repeat the procedure.

Such plastered surfaces don’t need to be puttied again.

This could be regarded as the plaster application’s completion. While there is no longer a need for additional steps, it is still important to create a comfortable drying environment for the solution. The space shouldn’t have any drafts or heating appliances running. The coatings should also be shielded from direct sunlight. To get rid of the extra moisture, the room needs to be ventilated after three days. Conditions for temperature: +5 to +25 degrees.

How to apply plaster using a machine

Plastering machines and other similar equipment are available in today’s construction markets. It should be mentioned right away that because of its high cost, renting is preferable for occasional or short-term use. The device is made up of a container that can hold the completed solution or its component parts, a feed hose, and a nozzle that adjusts the material supply’s intensity. A control panel, a compressor, and a power cable are also present.

How plaster is applied:

1. Load the finished mixture into the container.
2. Connect the equipment to the network and take the feed hose in your hands.
3. Direct it to the wall, while holding it 30 cm from the surface being treated.
4. Turn on the plaster supply and move from the bottom up.
5. Layers of material should overlap each other.
6. At the end, the material is leveled and rubbed in the same way as in the case of the usual application option.

How long does gypsum plaster dry

In a room with adequate ventilation and a specific temperature, the material fully dries and gains strength within 7 to 14 days. Upon full drying, the coating takes on a uniformly light hue. You can now move on to the next step of finishing. If tiles were selected, mounting them only requires the application of glue. In the event that painting is scheduled, the wall’s humidity level cannot exceed 1%.

Vital! It is not permitted to speed up the drying process of coatings by using heating equipment.

Gypsum plaster is a cost-efficient and adaptable wall finishing solution that produces a smooth surface perfect for a range of decorative uses. Professionals and do-it-yourselfers alike favor it for its simplicity of use and speedy drying time.

Still, the best outcomes depend on applying the technique correctly. This include properly priming the surface, properly blending the plaster, and evenly applying it.

You can make sure that your walls have an eye-catching, long-lasting finish by adhering to these guidelines.

Video on the topic

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