How to prepare and paint the walls and how to calculate how much paint to buy?

How to prepare and paint the walls and how to calculate how much paint to buy?

The walls should be properly prepared before painting. Fill any defects and damages with gypsum mortar, and then sand with sandpaper. If the wall is not even, it should be corrected with gypsum plaster and sanded. Before painting, a freshly plastered wall must be primed so that it does not absorb the paint. Wash off old paint layers with water and soap, to remove dirt and dust, and then plaster the defects and level the surface with sandpaper.

If we have walls covered with dark paints or wallpapers with a pattern and we intend to paint them in light colors, we should first prime them. If individual walls in the room (or their fragments) or the ceiling we want to paint in different colors, we will encounter particular difficulties in the corners and angles. In that case, it's best to wait, until one paint is dry, cover the edge of the painted wall with masking tape (with low adhesive strength), and then paint the other wall with paint.

Walls with old paint coatings should be washed with water with the addition of painter's soap before painting.
We start painting from the corners and from the upper strip (in contact with the ceiling) and lower (in contact with the skirting board). In the corners, use a narrow brush at corners and at the edges of other surfaces (ok. 5 cm) – we dip it in the paint to the middle of the bristle length, and wipe the excess paint on the edge of the can or litter box. In order not to soil the skirting board or the floor, it can be covered with masking tape. We secure other wall elements in a similar way, e.g.. light switches.
We paint the main surface of the walls with a roller or a brush with a bench. We start the work from the top and move downwards, starting from the right corner – Thanks to this, we will not catch the brush on painted fragments (left-handed people should start painting from the left side). However, this is not a mandatory rule. When the paint is dry, apply another layer, painting in the same way.

How much paint do you need to buy?

To calculate how much paint we will need, we need to measure the entire surface to be painted. The area of ​​a wall is its height multiplied by its length. So a wall with dimensions 5 x 5 m has an equal area 25 m2. When buying paint, check how large the surface is intended for the contents of the can. But let's not forget, that these are only estimates. In fact, the amount of paint needed will depend on the method of painting and the type of surface.