What Is Finished Plaster?
Once the walls are constructed, the next operation which follows is Plaster Finishing. It is done to ensure the evenness of the top surface of the walls and to achieve an aesthetic finish.
Use of mortar to cover the wall surfaces of readily constructed walls and ceilings in order to achieve an elegant and even finish. In this article, we will be discussing various types of plaster finishing and their properties.
In this article, we will be discussing various types of plaster finishing and their properties.
Types of Plastering Finishes
Types of Plaster Finishes used in Building Construction are:
- Pebble Dash Plaster Finish
- Scrapped Plaster Finish
- Textured Plaster Finish
- Stucco Plaster Finish
- Exposed Aggregate Plaster Finish
- Waterproof Plaster Finish
- Smooth Coat Finish
- Sand Faced Finish
- Rough Cast Finish or Spatter Dash Finish
- Depeter Finish
1. Pebble Dash Plaster Finish
It is a Plaster Finish in which small pebbles or crushed stones of suitable size (generally varying from 10 to 20 mm) are thrown onto a freshly applied final coat of mortar and left exposed.
The mortar for the final coat is usually made by mixing cement and coarse sand in the mix proportion of 1:3 and is placed in about 1 mm thickness.
The pebbles used for dashing should be well-washed and thrown wet onto the final coat. The pebbles may be tightly tapped into the mortar with a wooden float or with the flat of the trowel.
This finish of plaster possesses all the advantages of the roughcast finish and is recommended in similar conditions. The pebbledash plaster finish is mostly used for covering exterior walls and providing an aesthetic appearance to the structure.
2. Scrapped Plaster Finish
In many homes to create a good blend of smooth and rough surfaces, a scrapped plaster finish is created. It is a plaster in which the final coat, after being leveled and allowed to stiffen for a few hours, is scrapped with a steel straight edge old saw blade or other such tools to remove the surface skin.
Various types of scrapped finishes can be obtained by using different types of tools in different manners.
In this plaster finish, the final layer is usually 6 to 12 mm thick of which about 3 mm is removed in the scrapping process. The scrapping is done after the setting of the final coat has taken place.
In the process of scrapping, the surface skin of the mortar is removed to expose the aggregate and the texture obtained depends upon the grading aggregates used in the final coat. This plaster finish is less liable to crack than the plain finish.
3. Textured Plaster Finish
A textured plaster finish can be typically found on boundary walls or part of a feature wall to create a textured interior décor installation.
A textured plaster finish is created by making use of stucco plastering, finished with a rough surface but often smoothed over to create repetitive patterns.
For a textured finish mix of sand, cement, lime, and water is used blended with various additives such as fibers and synthetics acrylics, and even coloring pigments.
In this finish, ornamental finish or textured surfaces are produced by working with various tools on the freshly applied final coat. This finish possesses all the advantages of the rough finish.
4. Stucco Plaster Finish
Stucco plaster finish belongs to a type of plaster that provides a superior finish. This plaster can be applied to inside as well as outside surfaces.
It is usually placed in three coats which make the entire thickness of the plaster roughly 25mm.
The first coat is known as a scratch coat; the second one is a finer coat of brown coat and the third is known as a white coat or finishing coat.
5. Exposed Aggregate Plaster Finish
White and colored marble chips shall be of 6 mm to 12 mm size shall be used which obtained from crushing hard marble stones.
Exposed aggregate finish plaster shall be 20 mm thick. The procedure of application shall be the same as for the sand-faced finish. Mix proportion should be 1 cement: 1 marble chip and the pebbles to be used shall be well washed and drained.
The admixture shall be thrown wet onto the undercoat while it is still plastic using a strong whipping motion at right angles to the face of the wall. Loose mortar on the top surface shall be cleaned or removed by washing/brushing with a water jet.
6. Waterproof Plaster Finish
Cement waterproof compound of approved make and manufacture shall be used for plastering. These compounds shall conform to IS:2645.
Use of admixture consisting of calcium chloride shall not be permitted. The material should be brought to the project site in its original packing.
The compound shall be well mixed with dry cement in the proportion of 3% by weight or as recommended by the manufacturer.
Care shall be taken while mixing, to see that waterproofing material gets well and integrally mixed with cement and does not run out separately on the addition of water.
7. Smooth Coat Finish
This type of plaster finish is smooth in nature with leveled surface. The proportion of 1:3 is used for Sand and cement for making mortar used in finishing.
The application of mortar to the wall is done using a wooden float.
8. Sand Finish Plaster
This plaster finish is usually completed in 2 coats of mortar mix. The ratio of cement sand is kept 1:4 in mortar for the first layer with 12mm thickness.
Initially, the first layer is applied and then cured for 7 days, which is followed by the second layer with a thickness of 8mm.
As per requirement, the ratio is kept at 1:1 for the sand and cement mixture. The use of a sponge is done after when the layer is wet to add the required characteristics.
9. Rough Plaster
Rough finishing of plaster requires a Cement Sand Aggregate ratio of 1:1:3 for finishing work, having a coarse aggregate size of 3mm to 12 mm.
In this Finishing of the plaster surface, the mortar mix splashed on the wall, and then it is finished rough with the help of a float made of wood.
This finished plaster is more durable, waterproof and crack proof and crazing proof.
10. Depeter Finish
It is like most last finishing plaster coats which is having a thickness of around 12 to 15 mm for a good quality finish.
The materials of the Gravel Plinth are compressed to the required degree manually after the application of mortar. Gravel plinths could be used in different colors and shapes to give a colorful appearance to the wall.
Wall Plaster Material
To obtain the required characteristics for surfaces such as aesthetics, Heat insulation, durability, and much more properties there is the necessity to add some special materials with cement paste.
The followings are the wall plastering materials,
- Acoustic Plaster
- Asbestos Marble Plaster
- Barium Plaster
- Granite Silicone Plaster
- POP or Gypsum Plaster
- Keene’s Cement Plaster
1. Acoustic Plaster
There is usually a need to add gypsum in the mortar mix for surface finishing to resist the formation of a honeycomb. In the process of formation of a honeycomb, the surface coat is likely prone to undergo chemical reaction resulting in the formation of gas bubbles which in turn leads to the formation of small openings on the surface which eventually looks honeycomb-like structure.
The acoustic plaster has small pores opening it which absorb sound. Therefore, Types of plaster finishes are most used to cover a cinema hall and media room to a minimum of the eco echo effect.
2. Asbestos Marble Plaster
Asbestos Cement in addition to crushed fine marbles mixed with cement to obtain a perfect Surface Finish.
3. Barium Plaster
X-ray cabinets are very much prone to radioactivity which enforces the mixing of barium soleplate in mortar during the finishing works to ensure the safety of people working in such areas from radioactivity.
4. Granite Silicone Plaster
It is a plaster finish achieved by mixing silicon and granite with mortar. The use of such plaster finishes is done for constructions with superior characteristics.
It is an elastic in nature and quick in the setting. This plaster eliminates cracks on the surface
5. Gypsum Plaster
Plaster of parties is obtained by heating gypsum at 165° to 170° degree temperature. Plaster of plaster is get liquified within 5-8 minutes of heating
While Using POP appropriate retarder is combined with it to enhance the setting time of mortar. For crack repair and ornamental work, a POP is used with lime for good bond strength and finishing.
It is a lightweight, soundproof, and fire-resistant material used in construction.
6. Keene’s Cement Plaster
For manufacturing Keene’s Cement Plaster, POP is mixed with alum in fixed proportions. These types of plaster are used for decorative purposes as it looks attractive after hardening which and form a polish-like white glass after hardening in a few days.
In conclusion interior or exterior plaster finishes are vital elements in the construction and designing of building, exterior plaster finishes provide both protection and aesthetic appeal, shielding the structure from weather elements while enhancing its overall appearance.
Interior plaster finishes contribute to the visual appeal and functionality of interior spaces, providing smooth and even surface for further treatments such wall-papering and painting and they offer versatility in texture options, allowing for creative and customized interior design.
Skilled craftsmanship, proper surface preparation and attention to details are essential for achieving high-quality plaster finishes which is plaster finishes play a significant role in creating beautiful and functional spaces.
By utilizing the exterior and interior plaster finishes, designers and architects can enhance the aesthetic, protect the structure and create inviting environments which meet both design requirements and function requirements.
Can these plastering finishes be used interchangeably between exterior and interior surfaces?
While some plastering finishes can be used for both exterior and interior surfaces, certain finishes are specifically designed for either exterior or interior use. It is important to consider factors such as durability, weather resistance, and maintenance requirements when selecting a plastering finish for a particular surface.
Can plastering finishes be painted or coated?
Yes, most plastering finishes can be painted or coated with suitable materials. It is important to prepare the surface properly and select appropriate paints or coatings for good adhesion and longevity of the finish.
Can plastering finishes be repaired if damaged?
Yes, plastering finishes can be repaired if damaged. Depending on the extent of the damage, the repair process may involve patching, reapplication of plaster, or retexturing the affected area to match the existing finish.
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