Plastering entails smoothing down rough spots on walls, ceilings, and roofs by modifying, turning, or rendering the surface. After spreading wet materials over the block or brick works, the appropriate machinery is utilised to smooth and level the surface. Plastering is done so that a hard, smooth surface can be achieved, which can then be painted and make a room seem great.
Current trends have seen the exterior walls of homes finished with brick, block, or aesthetically attractive stone. The thickness of wet materials that spread over a wall or roof shouldn’t be more than 0.3 cm.
There are, however, areas where the imperfections are larger than 3 centimetres. Undercoat, a low-priced coarse-grain material is used to render the surface, and then a finish coat, a thin coating of fine-grain materials, is applied on top.
Furthermore, walls built with irregular and various-sized stones may need three coatings. This is because heavy, damp plaster might cause the undercoat to buckle. As a result, it is recommended to apply a small layer, wait for it to harden, and then apply a second undercoat.
Plaster Types Based on the Material Used
Lime Plaster
The ratio of sand to lime in the lime mixture is 1 to 3, by volume.
The mixture serves double duty as both an undercoat and a topcoat. To prevent cracking and shrinkage, animal hair of around 5 Kg is added to 1 m2 of lime plaster. Lime plaster has the potential to be employed in the repair and renovation of historic buildings.
Cement Plaster
To create cement plaster or cement stucco, you just combine cement, sand, and water. It’s a popular option for completing walls inside and out. Cement plaster is an excellent finishing material since it is fireproof, insect-proof, and highly resistant to the elements.
In addition to concrete, brick, and stone are other suitable substrates for the application of cement plaster. Depending on the intended effect and the current state of the surface underneath, it can be put in either thin or thick layers. It’s also versatile in that it may be used to create finishes that range from flat and smooth to rough and textured.
Gypsum Plaster
Plaster of Paris, or gypsum plaster, is a form of plaster manufactured from gypsum, a soft sulphate mineral consisting of calcium sulphate dihydrate. It’s a popular option for completing walls inside and out.
Because of its consistent appearance and low cost, gypsum plaster is frequently used as a wall covering.
It’s versatile and simple to apply, and it works well on many different materials. Depending on the intended effect and the current state of the surface underneath, it can be put in either thin or thick layers.
Gypsum plaster may be sanded and painted soon after it is applied, which is one of its benefits. It’s a great insulator and can keep a room at a comfortable temperature and humidity level.
Plaster Background Surfaces
Plastering a wall or ceiling can be done in a number of different ways, each of which requires a different type of plaster and a unique method of application. Plaster has the mechanical adhesion needed to stick to the walls or ceilings behind bricks or blocks with rough and firm surfaces. After wet undercoat plaster has dried, mechanical keys are generated that adhere the hardened plaster to the surfaces.
The cement in undercoat plaster contracts only so much before cracking, but plaster keys prevent this from happening.
It is easier to get plaster to stick to machine-pressed bricks because of their high density and flat surfaces, which are the result of the water absorption capabilities of the pressing machinery.
Suction is the quantity of water absorbed by dense, smooth-surfaced bricks, which facilitates plaster adherence.
Lightweight concrete block is notoriously difficult to plaster because of its enormous suctions. To lessen the amount of water absorption, a liquid primer or water spray should be used before plastering.
Two options for low-suction surfaces are the polymer bonding agent and the polyvinyl alcohol (PVA) bonding agent. The earlier technique involves applying a coat of polyvinyl acetate with a paintbrush and then covering it with a layer of plaster while the PVA is still tacky.
In the latter, the link is supplied by silica sand grain after the polymer has dried, having been treated with a combination of silica sand and polymer.
Beads and stops made of galvanised steel are commonly used to reinforce corners and edges of drywall and sheetrock. The beads are used everywhere plaster meets a different material, such as where the ceiling meets the wall.
Galvanized steel stops are used wherever plaster meets a different material, such at corners, around doors and windows, and along skirting, for a professional look.
Types of Plaster Finishes
Pebble Dash Plaster Finish
It’s a plaster finish achieved by scattering stones or pebbles of an appropriate size (10-20 mm) over a recently put top layer of mortar and leaving them there to dry.
As a final layer, mortar prepared from cement and coarse sand in a 1:3 mix ratio is typically applied at a thickness of 1 mm.
It’s important to thoroughly wash the dashing pebbles and then toss them wet onto the last layer. A wooden float or the flat of the trowel can be used to press the pebbles firmly into the mortar.
This plaster finish is recommended in the same settings as the roughcast finish since it shares the same advantages. Plaster with a pebbledash texture is commonly used to clad exterior walls and give the building a distinctive look.
Scrapped Plaster Finish
Many homes have a scraped plaster finish because it’s a nice compromise between smooth and rough. It’s a type of plaster where the top layer is scraped off with a steel straight edge, an old saw blade, or something similar after it has been levelled and allowed to harden for a few hours.
It’s possible to get a wide range of scraped finishes by employing a variety of tools and techniques.
The final coating of this plaster finish is typically between 6 and 12 mm thick, and the scrapping process removes around 3 mm. After the last coat has dried, that’s when you scrape it.
The texture achieved is determined by the grading aggregates used in the final layer, which is achieved by scraping the mortar’s surface skin away to reveal the aggregate. This plaster coating is more resilient against cracking than the standard coating.
Textured Plaster Finish
Plaster walls with a textured finish are commonly used as a part of an interior design scheme, either as a dividing wall or as a focal point.
To achieve a textured plaster look, stucco plastering is used, which has a naturally rough surface but may be smoothed over to make patterns.
A textured finish is achieved by combining cement, sand, lime, and water with additions like fibres, synthetics, acrylics, and even colouring pigments.
This finishing technique involves using a variety of tools on the freshly applied top coat to create a decorative finish or textured surface. This finish offers the same benefits as the rough one.
Stucco Plaster Finish
In terms of plaster finishes, stucco is among the best. This plaster is suitable for both interior and exterior use.
The standard application method involves applying the material in three coats, for a total thickness of around 25 mm.
The first layer, called a scratch coat, is followed by a brown coat, and finally a white coat, also called a finishing coat, is applied.
Exposed Aggregate Plaster Finish
White and colourful marble chips, obtained by crushing hard marble stones, must be between 6 mm and 12 mm in size.
The minimum thickness for the final plaster with exposed aggregate is 20 mm. The application process must be identical to that of the sand-faced surface. Pebbles to be utilised should be thoroughly washed and drained, and the mix ratio should be 1 cement to 1 marble chip.
A wet admixture should be placed onto a plastic undercoat employing a hard whipping motion perpendicular to the wall’s face while the undercoat is still wet. The top surface must be cleaned by washing and scrubbing with a water jet to get rid of any loose mortar.
Waterproof Plaster Finish
Plastering must be done with a cement waterproof compound of an approved make and manufacture. These chemicals must meet the requirements of IS:2645.
It is forbidden to use an admixture that contains calcium chloride. It is recommended that the materials be delivered to the construction site in their original packaging.
Dry cement, in the amount of 3% by weight or as specified by the manufacturer, must be well combined with the compound before use.
Waterproofing material must be thoroughly and integrally mixed with cement so that it does not escape in a separate stream as water is added during mixing.
Smooth Coat Finish
This particular plaster finish is extremely smooth and flat. Sand and cement are often mixed at a ratio of 1:3 to create a finishing mortar.
Mortar is spread onto the wall with a wooden float.
Sand Finish Plaster
Plastering typically requires 2 applications of mortar mix to achieve the desired finish. For the first layer, which is 12 millimetres thick, the cement-to-sand ratio in the mortar is preserved at 1:4.
After the first layer has been applied and allowed to dry for 7 days, a second coat with an 8mm thickness is applied.
The mixture of sand and cement is maintained at a 1:3 ratio, as specified. Whilst the layer is still wet, the sponge is used to blend in the necessary details.
Rough Plaster
Plaster with a bumpy and uneven surface is known as a rough plaster finish. The plaster is applied in a thicker layer than for a smooth finish, and then trowels, brushes, or sponges are used to provide texture and dimension.
The end product is a wall that looks natural and handmade, perfect for giving a room some personality.
Plaster kinds like cement, gypsum, and lime plaster can all be used to create rough plaster finishes. As the roughness of the plaster is varied, it may be used to create a wide range of visual and textural effects.
Depeter Finish
A decent-quality finish requires a thickness of between 12 and 15 mm for the final coat of plaster.
When the mortar has been applied, the Gravel Plinth’s components are manually crushed to the proper density. Colourful gravel plinths of varying sizes and shapes could be used to decorate the wall.
Choosing the Right Plaster Finish
The look and usefulness of your walls will be greatly affected by the plaster finish you choose. Several plaster coatings are available, each with its own set of advantages. If you want your walls to turn out the way you hoped, you need to be familiar with the steps involved in applying a plaster finish.
When choosing a plaster finish, one option to think about is the texture. Plaster can be finished in a variety of ways, some clean and modern, others rough and textured. The mood and look of a room can be affected by the texture used.
It’s also important to think about the colour of the plaster finish. White, beige, and even brighter tones are just some of the hues available for plaster. The mood or atmosphere you want to create in a room can be contributed to by the colour of the plaster used.
The longevity and practicality of your walls might also be affected by the plaster finish you choose. High-traffic areas or rooms that are subject to moisture may benefit from a plaster finish that is more resistant to moisture and wear and tear.
It’s also worth noting that the acoustics of a room can be modified by the type of plaster finish used. Plaster coatings with sound-absorbing characteristics are useful in noisy environments.
If you want your walls to look and perform the way you want them to, mastering the appropriate plaster finish is essential. When selecting a plaster finish, it’s essential to think about things like texture, colour, durability, and acoustics. If you want to make sure you have the correct plaster finish for your needs and preferences, it’s a good idea to consult with a professional wall plasterer.
Conclusion
Plastering is the process of modifying, turning, or rendering the surface of a wall, ceiling, or roof to remove imperfections. This is done to get a nice, hard, smooth surface that can be painted to make the room look fantastic.
Modern residential exteriors are typically finished with brick, block, or an aesthetically pleasing stone. Any wet material used to cover a wall or roof should be at least 0.3 centimetres thick; this includes the undercoat, which is made of coarse grain material, and the finish coat, which is made of fine grain material.
In addition to being resistant to fire and insects, cement plaster is also highly weatherproof.
Gypsum plaster is also adaptable, allowing for a wide variety of finishes, from sleek and flat to textured and rough. Due to its consistent visual appeal and low cost, gypsum plaster is frequently used as a wall covering.
It’s flexible enough to be applied in either thin or thick coats, and it’s ready to be sanded and painted soon after it’s been put up. An excellent insulator, it helps maintain a room’s ideal temperature and humidity. If you want to plaster a wall or ceiling, you’ll need to buy special plaster and learn how to do it properly.
To create a plaster finish known as “pebble dash,” stones or pebbles of the appropriate size are scattered over a fresh coat of mortar and allowed to dry in place. Mortar is typically applied at a thickness of 1 mm, and is made by mixing cement and coarse sand at a ratio of 1:3.
After the plaster has been levelled and allowed to harden for several hours, the top layer is scraped off with a steel straight edge, an old saw blade, or something similar to create a scrapped plaster finish.
Cement, sand, lime, and water are the base ingredients for plaster, and various additives such as fibres, synthetics, acrylics, and even colouring pigments are mixed in to create a textured finish. Plastering with stucco is ideal as both an interior and exterior coating.
The plastering work must be completed using a cement waterproof compound that has been approved for use and complies with IS:2645. Exposed aggregate must be at least 20 mm thick, and marble chips must be between 6 mm and 12 mm in size.
After applying a plastic undercoat, a wet admixture should be washed and scrubbed with a water jet to remove any debris. To achieve a smooth coat finish, two coats of mortar mix are applied to the surface.
Walls can have a rough, medium, or smooth plaster finish, or even a depeter finish, which all have distinct visual and functional effects.
Sound-absorbing plaster coatings are helpful in noisy settings. Talk to a professional wall plasterer to make sure you get the right plaster finish for your requirements and tastes.
Content Summary
- In addition to concrete, brick, and stone are other suitable substrates for the application of cement plaster.
- Because of its consistent appearance and low cost, gypsum plaster is frequently used as a wall covering.
- Plastering a wall or ceiling can be done in a number of different ways, each of which requires a different type of plaster and a unique method of application.
- Plaster has the mechanical adhesion needed to stick to the walls or ceilings behind bricks or blocks with rough and firm surfaces.
- Suction is the quantity of water absorbed by dense, smooth-surfaced bricks, which facilitates plaster adherence.
- Lightweight concrete blocks are notoriously difficult to plaster because of its enormous suction.
- To lessen the amount of water absorption, a liquid primer or water spray should be used before plastering.
- Two options for low-suction surfaces are the polymer bonding agent and the polyvinyl alcohol (PVA) bonding agent.
- The earlier technique involves applying a coat of polyvinyl acetate with a paintbrush and then covering it with a layer of plaster while the PVA is still tacky.
- Beads and stops made of galvanised steel are commonly used to reinforce corners and edges of drywall and sheetrock.
- The beads are used everywhere plaster meets a different material, such as where the ceiling meets the wall.
- It’s a plaster finish achieved by scattering stones or pebbles of an appropriate size (10-20 mm) over a recently put top layer of mortar and leaving them there to dry.
- A wooden float or the flat of the trowel can be used to press the pebbles firmly into the mortar.
- Many homes have a scraped plaster finish because it’s a nice compromise between smooth and rough.
- Plaster walls with a textured finish are commonly used as a part of an interior design scheme, either as a dividing wall or as a focal point.
- This finishing technique involves using a variety of tools on the freshly applied top coat to create a decorative finish or textured surface.
- The first layer, called a scratch coat, is followed by a brown coat, and finally a white coat, also called a finishing coat, is applied.
- The minimum thickness for final plaster with exposed aggregate is 20 mm.
- The application process must be identical to that of the sand-faced surface.
- Plastering must be done with a cement waterproof compound of an approved make and manufacture.
- This particular plaster finish is extremely smooth and flat.
- Sand and cement are often mixed at a ratio of 1:3 to create a finishing mortar.
- Plastering typically requires 2 applications of mortar mix to achieve the desired finish.
- For the first layer, which is 12 millimetres thick, the cement-to-sand ratio in the mortar is preserved at 1:4.After the first layer has been applied and allowed to dry for 7 days, a second coat with an 8mm thickness is applied.
- The mixture of sand and cement is maintained at a 1:3 ratio, as specified.
- Plaster with a bumpy and uneven surface is known as a rough plaster finish.
- The plaster is applied in a thicker layer than for a smooth finish, and then trowels, brushes, or sponges are used to provide texture and dimension.
- Plaster kinds like cement, gypsum, and lime plaster can all be used to create rough plaster finishes.
- A decent-quality finish requires a thickness of between 12 and 15 mm for the final coat of plaster.
- When the mortar has been applied, the Gravel Plinth’s components are manually crushed to the proper density.
- Colourful gravel plinths of varying sizes and shapes could be used to decorate the wall.
- The look and usefulness of your walls will be greatly affected by the plaster finish you choose.
- If you want your walls to turn out the way you hoped, you need to be familiar with the steps involved in applying a plaster finish.
- When choosing a plaster finish, one option to think about is the texture.
- The mood and look of a room can be affected by the texture used.
- It’s also important to think about the colour of the plaster finish.
- It’s also worth noting that the acoustics of a room can be modified by the type of plaster finish used.
- If you want your walls to look and perform the way you want them to, mastering the appropriate plaster finish is essential.
- When selecting a plaster finish, it’s essential to think about things like texture, colour, durability, and acoustics.
- If you want to make sure you have the correct plaster finish for your needs and preferences, it’s a good idea to consult with a professional wall plasterer.
Frequently Asked Questions About Plastering
Is plaster a costly material?
Plaster is more expensive than gypsum. Cement and cement lime plaster are cheaper alternatives. The substance used is chlorine, which is highly toxic in its pure form.
Is white cement the same as plaster?
White cement is not the same as plaster; it has a different consistency. The former, made of gypsum, is used to make casts for medical purposes (such as when repairing a fracture), while the latter is put on walls to make them shine.
Is plaster dangerous to one’s health?
Many people fear working with plaster because of its inherent dangers. Though it is not dangerous in the right hands, the substance is generally considered safe for everyday use. Anything embedded in the plaster runs the risk of being trapped and subjected to extreme heat.
Is plaster suitable to use on walls?
Plaster is the best option for repairing gaps in plaster walls because its properties are more likely to match the wall material. Plaster isn’t often used to repair drywall, but it does a great job of reinforcing interior walls.
Is plaster easy to maintain?
When you want to clean your Venetian plaster walls, all you have to do is wipe them down. In order to lengthen the life of walls, routine maintenance such as cleaning and sealing is recommended.