Interior paints: types of wall paint

1. Types of interior paint

Interior wall paints are categorised according to their composition and purpose. In terms of composition, there are synthetic-based wall paints (nitrocellulose or oil-based paints) and water-based ones. However, when it comes to purpose, there are primers and top coats. When choosing which paint to use for a certain wall, you need to know what kind of surface the paint will be applied to because interior paints differ in this regard, too.

2. Water-based paints

Water-based paints are the most popular choice for interior walls. They do not emit a strong odour and are also free from dangerous chemicals and harmful solvents. Due to their fast drying time, the painting process is also less time-consuming. They give a flexible finish that is resistant to cracking. However, you need to bear in mind that if applying a water-based paint over an oil-based one, you will need to go over the latter with sandpaper to prevent the new coat from peeling.

3. Oil-based paints

These contain natural or synthetic oil as a base. They can be used on almost all types of surface and give an attractive finish. They are ideal for rooms with a high moisture content, such as bathrooms and kitchens, but they do have a stronger smell and longer drying time than water-based paints. However, they can help conceal stains or small imperfections on the wall and are also richer in colour than water-based paints. In the long term, they are durable although the clean up after applying them is slightly more complex - you will need paint thinner or turpentine to clean brushes.

4. Silicate wall paints

Silicate paints use water glass as a binder. They are very resistant, so are mainly used for painting exteriors. With these paints, a layer of hard silicates is formed on the surface, which serves to protect it. Silicate paints are used in interiors to paint over lime substrates. This type of paint is abrasive, so it should be handled with great care. Safety glasses and protective gloves must be worn when applying it.

5. Limewash

Limewash is most commonly used for painting interior walls. As the name suggests, it contains lime as a binder. Although it is somewhat more demanding to work with, it is highly recommended as it is the healthiest type of paint. Limewash is not waterproof, so it comes off when in contact with a wet cloth - this is how you can tell whether the existing paint on the wall  is limewash. This type of paint is most often used in older and listed buildings.

5.1. Preparing the substrate for painting

The most suitable base for limewash is, of course, cement-lime mortar. Concrete surfaces will be more problematic. Limewash is applied to the wall as follows: the surface is first covered with a primer; the primer is watered-down limewash and consists of 70% limewash and 30% water. If it’s a surface which has been limewashed previously, there will be no need for a primer. However, you will need to pay attention to whether the existing paint is also lime-based or mineral-based. Limewash can be applied to walls with a roller and brushes, but it can also be sprayed on.