One of the most well-liked and dependable methods for creating a smooth, long-lasting surface on walls and ceilings is cement-sand plaster. Knowing how to make and apply this kind of plaster correctly is essential, whether you’re remodeling your house or starting a new building project. When done right, it offers a durable protective layer in addition to improving the visual appeal of your area.
Achieving the ideal blend is crucial. The strength and workability of plaster can be greatly impacted by the proportions of cement, sand, and water. It takes more than just following a recipe to ensure that the plaster will stick to the surface well and not crack over time. Care must be taken when mixing the plaster.
The most important factor in technique is application. Inadequate application can result in an uneven finish or a surface that deteriorates over time, even if you’ve created the ideal mixture. A polished appearance that endures over time can be attained with a few basic guidelines and some practice.
Step | Description |
1. Mixing | Combine cement and sand in a 1:3 ratio, then add water gradually until you achieve a thick, creamy consistency. |
2. Surface Preparation | Clean the wall of dust and debris, then dampen the surface with water to improve plaster adhesion. |
3. Application | Apply the plaster mix to the wall using a trowel, spreading it evenly in thin layers. |
4. Smoothing | After applying, smooth the surface with a straightedge or float to remove any excess material and ensure an even finish. |
5. Curing | Keep the plaster moist for several days by spraying water to prevent cracks as it dries. |
- Composition and features
- The ratio of components for cement-sand plaster
- Additional components for plaster
- Preparing the walls before applying plaster
- Splashing
- Soil
- Cover
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Composition and features
Because of its composition, cement-sand mortar is regarded as one of the simplest:
- Binding agent. Portland cement grade 100 to 500 usually acts as this component. Depending on the brand of cement, the finished coatings differ in quality. For interior decoration of premises, it is better to use more expensive materials marked 400-500. For external surfaces, high quality coating is not required, so it is acceptable to use cheap substances 100-300. It is important to remember that for the decoration of surfaces in damp rooms, it is strongly recommended to use Portland cement M500.
- Filler. In compositions of this type, it is customary to use an inexpensive filler – sand. The technology of manufacturing cement-sand plaster allows the use of any type of sand, the main thing is that it is cleaned and sifted. But it is better to opt for standard yellow quarry or river sand for plastering with a fraction of 20-40 microns. Before use, it must be sifted to remove shells and silt impurities.
- Solvent. In this case, ordinary purified water of any origin is used: water supply, well, natural reservoirs, etc. The main thing is to ensure that there are no solid fractions in the liquid.
The traditional ingredients for making cement-sand plaster are listed above, but the following materials are also added to enhance certain aspects of the finished product:
- Lime paste. Used to reduce the weight of ready-made mixtures, increase their plasticity and moisture resistance of finished coatings. The lime content is usually small: no more than 1 part of lime paste is required for 2 parts of cement. In this case, cement and sand are mixed first.
- Gypsum. This material is added in the compositions to accelerate the process of solidifying the surface and set of strength. This is usually required when processing ceilings and inaccessible places. Proportions of gypsum and cement – 1: 3. It is extremely recommended to pour more gypsum, since the finished solution will harden too quickly.
- Liquid soap or gel for washing dishes. No more than 3% of the total mass of the solution is required. This substance increases the plasticity of the material and makes the contact of the plaster with the wall more dense.
- PVA glue. The content of this component in the composition of cement-sand plaster should not exceed 5%. With the help of glue at home, you can polymerize the solution, which will increase its adhesive properties and increase the service life of finished surfaces.
You should know this! The quality of the finish is directly impacted by every component of the plaster mortar.
The ratio of components for cement-sand plaster
The most common solution is mixed in proportions of cement and sand 1:3, but depending on the brand of binder, the ratio of sand and cement can change several times. Water is added little by little until the plaster acquires the desired consistency. As for lime, its content should not be higher than the cement content, therefore the proportions of cement-sand material with the addition of lime test are as follows: 1: 3: 0.5. If the average plaster layer is planned to be about 2 cm, then the cement consumption will be about 6 kg per square meter, and 18 kg of sand will be needed. For a standard 25 kg bag of cement, you will need 2 standard bags of sand.
The steps involved in making cement-sand plaster are as follows:
- Cement and sand are poured into a plastic container in the required proportions and mixed with a hand tool (trowel, float).
- A special mixing attachment is inserted into the drill chuck and the tool is connected to the network.
- Water is added to the container in portions, constantly stirring the solution.
The end product should be a uniform mass of gray color that is devoid of any inclusions and has the consistency of thick sour cream. After 15 minutes in the container, it is mixed once more. Finally, soap or glue is poured in.
Additional components for plaster
Use the following materials to enhance or add characteristics to the material:
- Crushed mica. This material is necessary to protect the finished coating from exposure to ultraviolet waves. At the same time, the mineral for plastering walls significantly increases the alkalinity of the solution.
- Marble chips or flour. Most often, the substance is added to give the plaster decorative properties, but the stone also increases the strength of the surface.
- Quartz sand. Depending on the desired effect, the fraction of the mineral can be from 0.1 to 6 mm. Also increases decorative properties and improves resistance to acidic substances, including various detergents.
- Metal shavings. It is extremely rarely used for home repairs, but is used in industrial facilities to increase the strength of coatings.
- Expanded polystyrene. This polymer is used for insulation, so expanded polystyrene chips in the composition of cement-sand plasters will increase their thermal insulation.
- Crushed barite. It is used to protect coatings from radio wave exposure. Most often, barite plaster is in demand for finishing the walls of medical institutions, industrial premises and residential buildings located in contaminated areas.
It’s crucial to adhere to certain guidelines when applying and preparing cement-sand plaster in order to produce a smooth, long-lasting finish. To start, carefully combine the appropriate amounts of cement, sand, and water to form a uniform, workable mixture. Strong adhesion is ensured by appropriate surface preparation, which includes cleaning and dampening the wall. Using the appropriate tools to smooth and level the surface, apply the plaster in even layers, allowing enough drying time between coats to avoid cracking. You can achieve an aesthetically pleasing and long-lasting plaster finish by following these instructions.
Preparing the walls before applying plaster
Prior to anything else, the walls must be completely cleaned of all grease stains, paint residue, wallpaper, and other debris. Any reinforcement that protrudes from the wall must be ground down with a grinder, and any remaining material needs to be coated with an anti-corrosion liquid. All metal and plastic fasteners are eliminated from the surfaces.
After that, the resulting dust is removed from the walls and a primer is applied. This procedure needs to be performed at least twice, separated by at least four hours. This substance will improve adhesion and shield the walls from the growth of mold, mildew, and harmful bacteria.
Paint beacons are then installed after this:
- Measure 30 cm from the corner towards the center of the wall, and then install the first beacon. The product is checked for verticality with a building level.
- The same operation is carried out on the other side of the wall.
- Two threads are pulled between the parts, which will serve as a level for the rest of the beacons.
- Products are installed on the entire wall every 1.5 meters.
- After checking with a level, the beacons are fixed with the same plaster that will cover the wall.
Lastly, you must get ready all required supplies:
- For mixing – you need containers for dry components and the finished composition, an electric drill with a mixer attachment.
- For application – spatulas of different sizes, trowels, a rule.
- For grouting – graters, half-graters, a grinding machine.
Splashing
Compared to the main layer, a more liquid composition is used for the application of this first plaster layer. Using a spatula or trowel, the prepared plaster is gathered and then "thrown" to the surface. It is advised that home craftsmen use a trowel to process the walls if the master has experience, as this will eliminate the need for you to stretch and level the solution.
Note that the thickness of the splash depends on the substrate. Concrete is 3 mm, wood is 1 cm, and brick is 7 mm.
Soil
Installing the reinforcing mesh should come first. This can be used as a painter’s net or chain link, or for wooden surfaces, lath. The items are dragged onto the wall and fastened with screws in the middle and all the way around. Next, more mortar is moved to the wall using a wide spatula that has been gathered. Fill the space between the two beacons as a result, then use the rule to level the mortar while zigzagging upward from the bottom. Next, review the rule once more. It takes seven to ten days for the plaster to dry and solidify.
Cover
Since this is the final layer and needs to be of the highest caliber, plasters based on M500 cement that have gypsum or other mineral fillers added work best when applying them. In the event that the latter are present, the suggested layer thickness is 3 mm; otherwise, the layer thickness should match the filler fraction. Similar to the primer layer, the plaster is applied, but at the end it is rubbed with graters or half-graters and then ground with a grinding machine once it has dried.
To create walls that are both long-lasting and aesthetically pleasing, one must become proficient in the creation and application of cement-sand plaster. You can guarantee a sturdy and even finish that will endure over time by using the right mixing ratios, thoroughly cleaning the surface, and applying the plaster in layers.
In order to avoid cracks and make sure the plaster adheres well, it is important to pay attention to details like curing times and environmental conditions during application. Careful application techniques and consistency in the mixture will have a big impact on the result.
Even those who have never plastered before can tackle the job with confidence if they follow these instructions. An effective project requires careful planning and execution to produce a well-finished wall that improves the room’s overall appearance and longevity.