How to Level a Wall Corner

What happens if walls and corners are uneven? Wallpaper patterns break, they wear down in some areas, bamboo coverings peel off (despite permanent adhesive), pictures hang crookedly, and tiles begin to crack — this is far from a complete list of problems caused by such surfaces.

Uneven corners cause just as many problems and must also be leveled. There are several ways to achieve perfect condition: plastering with guides, using aluminum or plastic profiles, or sheathing with drywall sheets. Each option has its own nuances and is chosen based on existing conditions. Details on each below.

Plastering with Guides

If the indentations and protrusions at the corner are minor, and plane deviations do not exceed 1 cm, it is advisable to level them using plaster mix. For this, you’ll need a straight, flat, long pole, or a straightedge. Placing it vertically against the wall at the corner allows easy identification of the most prominent areas.

If possible, these irregularities should be chiseled or sanded down. Protrusions that cannot be removed will serve as guides — the extreme points of the future surface.

Guides can be marked with a pencil. Using a plumb line and level, determine the top and bottom points (for convenience, mark them on the floor and ceiling). At these points, create end guides with ready-mixed plaster, which will serve as the reference for leveling.

Always use a level to avoid further tilting. The same procedure is performed on the adjacent wall. The mix must set so that the guides are not damaged. Only then can plastering begin.

Plaster is first applied between the guides, then spread over the entire plane. After application, the corner area is leveled. A straightedge, special corner trowel, or regular trowel can be used. Apply the mix with a short trowel, and spread it over the surface with a long one.

Aluminum or Plastic Profile

To simplify the process, a special bent metal profile with mesh (contra-shulz) can be used. This adds extra protection, ensuring the corner will definitely be flat. The procedure is similar to the guide method, but the profile ensures perfect flatness.

After identifying problem areas, the corner is filled with plaster mix. The profile is pressed into the plaster and leveled. After installation, excess plaster is removed with a trowel.

This method eases work but requires additional effort to align the protruding mesh edges with the wall. The width of the plastering grip will be 20–30 cm on each side.

It’s unlikely the deviation can be corrected in one go; the mix must be applied multiple times. Once dry, the plaster can be sanded with sandpaper to hide the mesh edge.

Leveling with Drywall

This method is used when plane deviations are significant. Applying large amounts of plaster is not only uneconomical but sometimes impossible. The layer required to fix defects may exceed the maximum allowable thickness for the mix. In such cases, using drywall sheets is the most rational solution for leveling walls and corners.

Regardless of the chosen leveling method, remember that uneven corners can only exist on uneven walls. Therefore, first assess the wall’s flatness — you may need to level the wall itself.