A vital step in wall finishing that guarantees a robust, long-lasting, and smooth surface is applying cement-lime plaster. Because it combines the flexibility and workability of lime with the strength of cement, this type of plaster is widely used and can be applied to a variety of surfaces.
It’s crucial to correctly prepare the plaster mixture and the surface before beginning the plastering process. The level of preparation has a direct bearing on the outcome. Whether you’re painting a freshly painted wall or remodeling an existing one, paying close attention to detail in the early stages will streamline the application process and guarantee a durable finish.
This post will walk you through all the essential procedures for setting up and applying cement-lime plaster, from choosing the appropriate supplies to getting an impeccably smooth finish on your walls. You can improve the strength and visual appeal of your wall finishes by doing these steps.
- Where is cement-lime plaster used
- Advantages and disadvantages of the mixture
- Independent production of quicklime
- Slaking lime
- Preparation of cement-lime mortars
- Additional components
- Requirements for plaster
- Preparatory work
- Preparing surfaces before plastering
- Installation of paint beacons
- Application of cement-lime plaster
- Video on the topic
- Cement-lime plaster is durable or not? Reviews.
- How to cheaply and efficiently plaster the walls of a house with lime mortar.
- Cement-lime plaster
Where is cement-lime plaster used
These mixtures are typically used to finish interior surfaces in homes, but they can also be used in commercial, industrial, and public settings depending on the additional ingredients and the proportion of cement, lime, and sand. Finishing surfaces is also allowed on facades, basements, and covered loggias and balconies. This material is not appropriate for external surfaces in humid climate zones or for finishing walls where large furniture or equipment is intended to be hung.
Vital! Plastering walls with such compositions allows for an air humidity of no more than 65%.
Advantages and disadvantages of the mixture
When discussing the advantages of this content, the following points need to be made clear:
- Relatively low cost. If you prepare the mixtures yourself, they will cost 2 times cheaper than factory-made compositions. At the same time, ready-made cement-lime mixtures are 1.5 times cheaper than gypsum.
- Thermal insulation. Walls finished with cement-lime plaster require additional insulation only in cold latitudes.
- Vapor permeability. This feature ensures normal ventilation of the walls, which significantly increases the service life of the coating.
- Elasticity. This characteristic ensures the integrity of the surfaces during shrinkage of houses.
- Health safety. When heated, wet or in contact with chemically active substances, cement-lime solutions do not emit toxic substances.
- This material tolerates temperature changes, frosts and even prolonged direct exposure to fire without destruction.
- Good level of adhesion. Thanks to this, the plaster can be laid on most types of bases.
- Biological safety. Pathogenic bacteria and fungi do not develop on such coatings, in addition, lime prevents rodents from entering the home.
Although they are few, drawbacks do exist:
- Low mechanical strength, due to which the plaster layer can be easily damaged by direct exposure.
- Low moisture resistance, limiting the scope of application of solutions.
Independent production of quicklime
It should be noted up front that purchasing burnt lime is quicker and easier, but regular lime is required if you wish to complete the entire process. Because the material is used in many different industries, you can find out if there are any brick or building mixture factories nearby. If not, you’ll need to search online for a supplier.
You’ll need an oven for the next procedure. Once the temperature rises, it must be melted with coal. Add a little more coal and level the material in the oven to create an even layer. As soon as possible, lime is applied, and then a small amount of coal dust is sprinkled on top. The oven is then closed and left overnight. The lime is taken out of the oven and placed into a metal container in the morning. Because the material will still be very hot, you will need to wear safety glasses, gloves, and pliers. You must use a hammer to smash the lime once it has cooled before you can begin slaking.
To achieve a smooth and long-lasting finish, careful application, precise mixing, and appropriate surface preparation are crucial when working with cement-lime plasters. The base must be cleaned, the proper amounts of cement, lime, and sand must be mixed, and the plaster must be applied in layers. It’s an essential skill in wall finishing projects because by following these steps, you can achieve a strong and even surface that’s ready for additional finishing or painting.
Slaking lime
The following is the typical procedure:
- Quicklime is placed in a metal container and filled with cold water 1:1.
- After the end of the violent reaction, accompanied by boiling and hissing, you need to add a little more water so that the material is completely covered with liquid.
- Then you need to mix the solution, add water again, cover the container and leave the lime to infuse for 14 days.
Vital! Continue slaking until a homogeneous, bubble-free lime paste forms. If not, the plaster will crack as a result of the solution’s continued reaction with the walls.
Preparation of cement-lime mortars
Premium cement (M500) is needed to prepare a solution for finishing; M200 is good for rough work. Cement-lime plaster standard proportions are one part cement, one part lime paste, and 2.5 parts sand. Water regulates the final mortar’s fat content, so the amount needed depends on the plaster layer, the precise mixing ratio, and the necessary surface quality.
Mix the dry ingredients first, then add them to the lime dough, stir, and dilute with water to make plaster. You must calculate the plaster consumption per square meter in order to calculate the necessary amount of solution.
Additional components
There are instances where the coating’s quality needs to be raised or specific qualities added. You can use the following supplies for this:
- Expanded polystyrene chips. Sheets of this material are used for thermal insulation, so it should only be added to the plaster when finishing interior surfaces.
- Crushed mica. The mineral protects walls from ultraviolet rays.
- Marble dust, flour or chips. This material increases the mechanical strength of cement-lime plaster, as well as its decorative properties.
- Crushed barite. This mineral is practically not used for residential premises, since it protects coatings from radio wave radiation.
- Quartz. The fraction of this mineral can be from 0.1 to 6 mm. It has the same effect as marble, but additionally protects against acids.
Requirements for plaster
The following conditions must be satisfied for the plaster coating to have the required performance indicators and a long lifespan:
- All ingredients must first be cleaned of various debris (stones, shells, clay) and filtered through a sieve. It is also better to strain the prepared solutions. For spraying and soil, a sieve with a 3 mm mesh is suitable, for covering – 1.5 mm.
- The spray should contain more cement to increase strength, but at the same time more water to make it easier to apply.
- The use of additional components is possible only if necessary. Otherwise, the cost of the solution will be unreasonably high.
You will need to add water if the solution is hard to apply and tear. Should it disperse across the surface, additional dry ingredients must be added.
Preparatory work
To complete this step, you will require the following supplies and equipment:
- Hammer and set of chisels for removing old coating
- Scrapers, metal brushes and spatulas for cleaning the surface.
- Solvent and rag for removing paint.
- Hammer for tapping the surface.
- Sander and set of circles.
- Primer and paintbrush or roller for applying it.
- Container, drill with attachment or special construction mixer for making mortar.
Preparing surfaces before plastering
Take off previous coatings first. Sand the base, knock off the plaster, and remove paint using a solvent or a machine. Scrape and soak the wallpaper. Next, give the wall a thorough inspection while tapping it with a hammer. The fragile pieces should all be taken out, and polyurethane foam should be used to seal any wall cracks. After another round of sanding, the surface is cleared of dust.
Vital! Before starting any work, make sure you find the electrical wiring and turn off the power in the room.
After that, apply a primer to the surface. It is preferable to repeat this twice, separated by four hours. Installing a reinforcing mesh is necessary if surface reinforcement is needed. Regular screws are used to secure the product in the center and around the periphery. For interior work, this process is frequently not necessary.
Installation of paint beacons
These items are metal profiles oriented vertically, which are required for level plaster application. Instructions for installation:
- Installation begins from opposite ends of the wall. Retreat 30 cm from the corner, then use the level to draw a vertical line from the floor to the ceiling.
- Several portions of the solution are applied along this line, on which the first beacon is attached. The finished structure is checked with a level.
- The same operations are carried out for the opposite end of the surface.
- A screw is screwed into the upper and lower parts of the installed beacons, with the help of which two nylon threads are pulled. The gap between the thread and the beacon should be no more than one mm.
- Under the threads at a distance of 1.5 meters beacons are mounted along the entire wall.
- At the end, all products are aligned according to the thread level, pressing them to the required depth.
You should know this! When choosing them, beacon quality must be taken into account. They must be smooth and stiff.
Application of cement-lime plaster
We refer to the top layer as splashing. It makes sure that the plaster and wall are in the densest possible contact. To do this, a more liquid solution is made and then merely thrown onto the wall using a trowel or spatula. Although alignment is usually not necessary, it is preferable to use one of the hand tools to stretch the mixture slightly across the surface.
The primer is the next layer. Given that this is the plaster’s central component, its thickness may reach 5 cm. Using a broad spatula, the material is applied up to the beacons’ level, and then the surface is swept with a rule. You have to work your way up from the bottom, moving in zigzag patterns, and then repeat the process.
When using a rule, the solution that is still on the tool’s blade should be thrown onto the wall’s upper sections.
Following that, you should take the beacons off and wait a few hours for the solution to take effect. Using narrow spatulas, the corners and areas close to the ceiling and floor are completed after the resulting furrows are sealed with a mixture of the same consistency as for the main work.
Final application. This layer is finished, so its thickness shouldn’t be greater than 3 mm, and the coating should have a good quality. After applying the material and leveling it with spatulas and cells, they are polished and treated with graters once they have dried.
Note: You can start additional finishing work only after 14 days, to allow the wall to strengthen and dry out.
Step | Description |
1. Surface Preparation | Clean the wall from dust, dirt, and loose particles. Dampen the surface with water before applying the plaster. |
2. Mixing the Plaster | Mix cement, lime, and sand in the right proportions. Add water gradually to achieve a thick, creamy consistency. |
3. Applying the Base Coat | Apply the first coat of plaster with a trowel, pressing firmly to ensure good adhesion. Let it set slightly but not fully dry. |
4. Smoothing the Surface | After the base coat has set, apply a second, thinner coat. Smooth the surface with a straight edge or a trowel. |
5. Final Finishing | Once the plaster is partially dry, use a damp sponge or float to create the desired texture or smooth finish. |
Acquiring a long-lasting and visually appealing wall finish requires mastering the preparation and application of cement-lime plaster. Even though the process is simple, it does require careful attention to detail, particularly when it comes to evenly applying the layers and mixing the components in the proper proportions.
Cracking and poor adhesion can be prevented by making sure the mixture is prepared correctly and the surface is well-prepared. After taking your time and paying close attention to each step, you’ll have a level, smooth surface that will be a solid base for any additional wall finishing.
The proper method for cement-lime plastering can have a big impact on the result, whether you’re working on new construction or renovations. You can accomplish expert results that improve the longevity and beauty of your walls with time and practice.