Tips to Repair Wall and Floor Cracks

Cracked Floor TilesCracks can be very dangerous for houses, especially when they occur on the whole building or on a two storey building. It would be much better to plan for home renovation because structural cracks might endanger the family members’ lives. Yet, if it is only a hair crack, or structural crack on some points only, you can use another way to deal with it without having to do a big house renovation.

Therefore, the first step to do is to find the type of cracks:
Hairline cracks
This crack is less than 1 mm in width and does not penetrate to the other side of the wall due to imperfections at the time of finishing the walls, such as: wall plaster that is not watered first, bad stucco composition, not quite dry plaster, or wall paint with bad elasticity.

Expand the section of the hairline cracks to determine the crack level so when patching the cracks you can make sure that it reaches the right wall depth. Then fill it with wall filler, sandpaper after completely dry, then seal it with a sealer before repainting the wall.

Structural cracks
This crack is more than 2 mm in width and can be seen on the other side of the wall. This is because of:

  • The dropped or settled foundation due to soil’s poor bearing capacity or the less dense soil. This could be due to poor soil conditions or changes in soil characteristics caused by natural disasters such as floods, soil movement or earthquake.
  • The size of the foundation that does not match the load it bears or the poor foundation construction process.
  • Damage to the column and block, like cracked or bent. It can be due to the lack of the number or size of the main iron and binder iron (stirrups), the low quality of concrete used, or the poor making process.

Solution :

  • For the cracked column, create additional columns near the crack to split loading on the broken column or you can strengthen the column by injecting / grouting with epoxy liquid and widen the size of the column.
  • For small cracks in the columns and beams, just add the plaster so the iron is not in contact with the outside air which can lead to rust.
  • For the settled foundation, you should make a new foundation next to the old one by detecting the most severe cracks on the wall above it. Dense the soil under the new foundation and make a new pole to help distributing load to the upstairs.
  • For the cracked block, if possible you should add a column under it so that the block’s load distribution will reduce. If not possible, inject the block (grouting) using epoxy or chemical liquid that is binding and easy to dry. After that, expand the block size with reinforcement from the outside.

Floor cracks
Crack on the floor, especially on the second floor, is marked by the outbreak of tiles caused by the cracked concrete underneath. This could be due to an earthquake, the quality  of concrete that does not meet the standards, or  a technical fault during the concrete floor construction.

For cracked concrete floor, remove the damaged tiles and scrape the cracks, inject/grout with epoxy liquid on the cracks, plaster them, and install the tiles back.

If these cracks are signs of structural damage, this can not be considered a small problem because it involves the lives of its inhabitants. You should consult it with people who understand the structure of the building (civilian experts) to analyze the extent to which the location of the damage.

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