Everything you need to know about interior plastering – fundamentals, types, and applications

Interior plaster has an impact on the indoor climate, safeguards the building structure, and can greatly enhance the comfort of living. Whether it is for a new construction or renovation project, selecting the appropriate interior plaster is pivotal for achieving the desired visual appeal and creating a pleasant atmosphere within one's living space.

Interior plasters are not only functional, but they also play a vital role in enhancing the aesthetics and creating a sense of well-being in a room. However, selecting the right plaster can be challenging due to the wide range of options, each with its own unique advantages and characteristics. Whether you are seeking a breathable wall solution for a healthy indoor climate or a special texture that visually enhances a room, choosing the appropriate topcoat as well as basecoat is crucial

This article provides you with a comprehensive overview of the various types of interior plaster, their characteristics, and how to select the best plaster for your specific needs. Join us on this journey and explore the full range of possibilities that modern wall design has to offer.

An Introduction to Interior Plastering

The topic of interior plastering may appear simple at first glance, but it hides a complex world behind it that has a significant impact on the ambiance and functionality of every room. Interior plaster is not only a protective layer for the walls, but it also adds the final touch to them. In this regard, a distinction is made between the base plaster, which levels the substrate, and the decorative plaster, which serves as a design element. If the substrate consists of leveled plasterboards, a base plaster is not necessary as they are already smooth enough

The base plaster – also known as the undercoat – can be painted, wallpapered, or decorated with a top coat, also known as a decorative plaster.

Given that the interior of our home or workplace is the place where we spend a majority of our time, it is crucial to make the right choice when it comes to interior plastering. This is because it plays a significant role in determining whether a room feels warm and welcoming or rather cool and functional

The history of plasters

For millennia, people have been utilizing plasters to safeguard and enhance their dwellings. The history of plasters is as ancient as the history of architecture itself. In early civilizations, basic materials like clay or mud were utilized as plasters to fortify walls and shield them from weathering. As time went on, the technique progressed, leading to the usage of a variety of plaster types that served not only a protective purpose but also a decorative one

During the Renaissance and Baroque periods, elaborate plaster works flourished. Nowadays, we have access to a wide range of plasters that build upon centuries of experience in processing and applying building materials.

The Fundamentals of Plastering

Plastering walls is both an art and a science deeply embedded in the construction industry. It involves more than just covering a wall with a layer; it requires proper preparation and treatment to ensure durability and aesthetics

The primer, a type of undercoat, is the first step. It ensures that the plaster adheres well to the wall and serves as a foundation for the subsequent base coat. The base coat forms the initial thick layer, which is applied directly to the wall and gives it structure and strength. Finally, the top coat is applied onto the base coat, and if needed, another coat of primer may be applied beforehand to achieve a smooth, textured, or refined surface, which is often the visible end result

Throughout the entire process, it is crucial to use the correct materials and techniques to ensure that the interior plaster is not only visually appealing, but also functional.

When choosing interior plaster, you should consider the following questions:

Grain size and its significance

The grain size of a plaster refers to the size and texture of the particles. It plays a crucial role in determining the appearance and texture of the finished topcoat. A fine grain (for example, 0.5 – 1 mm) creates a smooth and uniform surface, which is highly valued in modern interior spaces. In contrast, a coarse grain produces a rustic and textured wall, often preferred in traditional or rural environments. The grain size not only affects the aesthetics, but also the application of the plaster. Larger grains are easier to apply and can better conceal imperfections. When working with a topcoat that has a fine grain, it is important to be meticulous in order to achieve a uniform surface

It is therefore crucial to select the appropriate grain size based on the desired end result and the specific requirements of the project. If a decorative plaster is desired on the base coat, it is important to choose a fine-grained plaster for the base coat. For our decorative doppo Ambiente wall filler, we recommend a maximum grain size of 1 mm for plastering

The role of the binder

The binder in a plaster plays a central role: it binds the individual components of the plaster together and ensures its adhesion to the wall

There are various types of binders, and their selection influences both the characteristics of the plaster and its visual appearance. For instance, lime, a traditional binder, produces breathable plasters that contribute to regulating the indoor climate. Gypsum allows for a smooth, finely textured surface and a thinner layer thickness. Additionally, interior plasters with binders based on clay or cement, as well as organic-based plasters with synthetic resin, are also viable options. It is recommended to seek advice from a professional.

Difference Between Interior and Exterior Plaster

While both interior and exterior plaster serve the purpose of enhancing and safeguarding surfaces, there are significant differences in their composition and intended use

The purpose of interior plaster is to improve the indoor climate, regulate acoustics, and provide an aesthetically pleasing surface. While it is subjected to fewer weather elements, it should still be breathable and contribute to moisture regulation

On the other hand, the exterior plaster needs to be durable and resistant to changing weather conditions, UV radiation, and mechanical stress. Water repellency plays a key role here, without compromising breathability, in order to prevent the formation of mold. Additionally, exterior plasters often include special additives that enhance their resistance to algae and fungal infestation.

Types of Interior Plaster

The interior design of walls is as diverse as the desires and needs of the people who inhabit these spaces. Interior plasters play a crucial role in creating the aesthetic and functional appearance of interiors

There is an impressive variety of interior plaster types that differ in their composition, structure, and appearance. Each of these plaster types brings specific properties and advantages, ranging from moisture regulation to sound absorption. But which type of plaster is the right choice for your project? In this section, we will guide you through the different types of interior plasters, explain their characteristics, and highlight the situations in which they are particularly beneficial.

Lime plaster

Lime plaster has a long-standing tradition in the construction industry and continues to hold great esteem today, primarily due to its numerous positive properties. As a natural binder, lime offers a range of advantages that make it highly appealing for interior spaces

Lime plaster is breathable and actively contributes to regulating the indoor climate by absorbing and releasing moisture. Furthermore, it has antibacterial properties, which is particularly advantageous for allergy sufferers and helps create a healthy living environment. From an aesthetic standpoint, lime plaster creates a warm, matte surface that is available in a wide range of colors and textures

In combination with its environmental friendliness and durability, lime plaster is an excellent choice for those seeking a natural and simultaneously functional wall solution for the interior.

The application of pure lime plaster requires careful handling, as it is highly alkaline. This means that it should not come into contact with the eyes or skin, and it is important to wear protective clothing and glasses while applying it. Additionally, it is recommended to avoid contact between the damp plaster and metal parts, window glazing, or surrounding surfaces. However, it is worth noting that the high pH value not only poses risks but also effectively inhibits the growth of mold.

Gypsum plaster

Gypsum plaster is often the preferred choice in many interior spaces, and for good reason. It features a fine texture that allows for a particularly smooth and even surface, making it perfect for those who desire a flawless finish for their interior walls

Due to its quick drying times, gypsum plaster can be processed and painted or wallpapered swiftly, thereby expediting construction and renovation projects. Another advantage is its design versatility – with gypsum plaster, various textures and patterns can be effortlessly created

In addition, gypsum plaster contributes to a pleasant indoor climate due to its moisture-regulating properties. Gypsum plasters ensure a good indoor climate by maintaining a constant level of humidity and being breathable. As a result, they are highly suitable for dry rooms as well as for damp areas, although not recommended for wet rooms. In environments with constant moisture, such as swimming pools, the plaster may deteriorate over time. However, it can be effectively used in kitchens or bathrooms. Gypsum plaster is resistant to mold growth due to its lack of organic ingredients. Its ability to effectively smooth out minor irregularities and provide an optimal base for further wall treatments makes it one of the most popular types of plaster for indoor applications.

Clay plaster

Clay plaster represents a millennia-old tradition in construction and is in high demand today, particularly in ecological building and renovation projects. Its natural composition, free of chemical additives, makes it an ideal building material for creating a healthy and pleasant indoor climate

Clay plaster has the ability to absorb moisture from the air in a room and release it when necessary, effectively regulating humidity levels. This not only creates a comfortable living environment, but also helps prevent the formation of mold. Clay plasters are excellent at storing heat and can absorb up to nine times more moisture than plaster. Additionally, they have the ability to filter out allergens and fine dust particles. However, it’s important to note that clay plasters are water-soluble, which means their usage outdoors is limited.

From an aesthetic perspective, clay plaster provides a warm and earthy appearance that evokes a feeling of naturalness and comfort

Its versatility also allows for the creation of various textures and color tones to fulfill individual design preferences. For those who prioritize sustainability, health, and a wall design that embraces nature, clay plaster is the ideal choice for indoor areas.

Silicate plaster

Silicate plaster, a construction coating material consisting mainly of mineral components but also containing a small amount of synthetic resin, has become increasingly popular in recent years, primarily due to its exceptional durability and environmentally friendly properties

Silicate plaster, based on the natural binder potassium water glass, is known for its high diffusion capability, which guarantees excellent breathability and thus a pleasant indoor climate. Moreover, silicate plaster is highly resistant to algae and fungal infestation, making it an excellent choice for exterior applications. However, it also offers benefits indoors due to its anti-allergenic and pollutant-binding properties. From an aesthetic perspective, silicate plaster provides a matte and even surface that comes in a wide range of colors and textures

Other specialized types of plaster

In addition to traditional types of plaster such as lime, gypsum, or clay plaster, there are several special types of plaster that each have their own unique advantages and characteristics. One example is decorative plaster, also known as textured plaster, such as the doppo Ambiente Wall, which enables creative wall design with various patterns and textures

Each of these types of plaster has its specific areas of application and can be chosen according to individual needs and preferences. They all offer a wide range of design possibilities and can contribute to giving a room that special touch.

Mineral plasters versus synthetic resin plasters

Mineral plasters, including lime, cement, and silicate plasters, are derived from natural raw materials. They possess exceptional breathability, moisture regulation, and contribute to a healthy indoor environment. These natural qualities make them environmentally friendly and often a suitable choice for historic buildings or eco-friendly construction projects

On the other hand, synthetic resin plasters are based on synthetic binders. They are known for their exceptional elasticity and ability to effectively compensate for movements in the underlying surface. This significantly reduces the risk of cracks. Synthetic resin plasters also exhibit excellent adhesion to various substrates, allowing for thinner application compared to mineral plasters. Additionally, they offer a wide range of design possibilities in terms of color and texture.

Application and technique

The art of plastering requires not only the right materials, but also the correct technique and application. The process often starts with the application of a primer, which ensures good adhesion of the plaster to the wall. In most cases, a reinforcing fabric is also embedded in the base coat to prevent cracks and enhance the stability of the plaster

The technique of applying plaster varies depending on the type of plaster and the desired result. Some plasters are directly applied to the wall by using a spatula, while others are sprayed or rolled on. Each technique requires specific tools and a particular approach to achieve optimal results. Factors such as drying times, mixing ratios, and any potential additives also play a role in the process

The correct application and technique are crucial for the longevity, appearance, and functionality of the plaster. Those who are unsure should always seek the advice of professionals.

Conclusion and maintenance

After the plaster has been properly applied and dried, a meticulous finishing is essential to maintain its beauty and functionality in the long term. Often, a protective coating or a top plaster finish is applied to minimize dirt and wear and to enhance the appearance of the surface. The final finish may vary depending on the type of room. In damp areas, such as bathrooms, the lime-white cement plaster double ambient wall offers a balancing property for high humidity. Additionally, the highly elastic double Ambiente Pro+ is also ideal for both wall and floor applications. For other wall surfaces that require a special highlight, we also recommend the distinctive and individual double ambience wall.

However, it is not only the completion, but also the regular maintenance of the surface that is crucial. Cleaning should always be done using products suitable for the specific type of plaster, while avoiding aggressive chemicals. The manufacturer’s safety data sheet and technical specifications provide valuable information in this regard

If necessary, plaster surfaces, decorative coatings, or paint can be refreshed or recoated after a few years to maintain them in pristine condition

Frequently Asked Questions

What is the difference between the base coat and the finishing coat?

The base coat serves as the initial layer directly on the wall and its purpose is to level out unevenness, stabilize the wall, and create an ideal foundation for the top coat. The top coat is the final layer that is applied directly onto the base coat. It determines the aesthetic appearance of the wall and can have various textures, colors, and effects based on preferences.

Can I use any type of interior plaster in a damp room?

No, not every interior plaster is suitable for damp rooms like bathrooms or cellars. In these areas, it is important to use a special plaster that is resistant to moisture and prevents the growth of mold. It is crucial to choose a plaster that is specifically designed for use in wet environments.

How does the grain size affect the final result of the plaster?

The grain size of a plaster refers to the size and texture of its particles. A fine grain size creates a smooth and even surface, while a coarse grain size produces a textured and rustic wall surface. The choice of grain size influences both the tactile sensation and the visual appearance of the plastered surface.

What role does the binder play in the plaster?

The binder is a crucial component of the plaster. It binds the individual components together and ensures that the plaster adheres to the wall. Depending on the type of binder, the properties of the plaster, such as breathability, durability, or flexibility, can vary. It also determines how the plaster can be processed and how it will behave over time.