If the plaster has come off the wall in places after repairs or has cracked, what could be the reason, and is it possible to fix the defect without new puttying

The last thing that anyone wants to see after a renovation is plaster falling off the wall or cracks appearing. These problems can be upsetting, particularly if the work initially appeared flawless. However, why does this occur and what can be done to stop it?

There are several reasons why plaster can split or come away from the wall. It could have to do with the substances employed, the way the surface was prepared, or even the room’s atmosphere. Resolving the issue successfully requires an understanding of its underlying causes.

Fortunately, it is frequently possible to fix these flaws without having to start from scratch. Through careful assessment and application of appropriate techniques, it is possible to restore your walls without having to resort to extensive re-puttying.

Inadequate preparation of the surface, improper material mixing, or ambient conditions like humidity are frequently to blame for plaster that has cracked or come off the wall in spots after repairs. If the wall is stable and dry, the damaged areas can be carefully cleaned and repaired, and the proper patching techniques can be used to address these defects without having to reapply putty in many cases. This method can repair the wall’s appearance while saving time and money.

Reasons for cracks in plaster, how to seal them and prevent them

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The causes of surface swelling, delamination, and cracks in wall plaster are discussed in the article. It also goes into great detail on how to patch up cracks in walls and stop plastered walls from breaking right away.

Reasons for cracks

Erroneous solution composition may lead to plaster swelling. If unseasoned lime—which contained unquenched particles—was used, the walls might develop tiny swellings after the lime was applied. The coating will eventually completely degrade. You must remove any bubbles from the plaster before applying a higher-quality composition to the surface to stop this from happening. Additional explanations

  • Cracks can appear when using poorly mixed or greasy solutions. Fat solutions are those that contain an excess of binders.
  • Cracks also occur due to surfaces drying too quickly. To prevent this from happening, you need to prepare the plaster strictly according to the instructions, scrupulously stir the composition before applying it to the walls.
  • It can come off the wall due to excess moisture on the wall or an excessively dry surface.
  • It is also recommended to wait until each applied layer dries, and apply the finishing coat to a completely dry wall.
  • On a new wall in a new building, it is worth using concrete contact before each new layer of plaster, this will ensure adhesion, which is absent without preliminary surface treatment.
  • You shouldn"t plaster the walls in an unheated room before frost.

Why do walls crack after plastering

A wall will undoubtedly crack if plaster composition is applied without adhering to technology:

  1. Aerated concrete is vapor-permeable, because of this, the plaster that is applied to aerated concrete must also be vapor-permeable. It is even better if it has a stronger vapor permeability than aerated concrete, otherwise the steam will accumulate in the coating, and it will crack.
  2. You should also remember that the finishing must be done in one day. Otherwise, the next day there will be a different air temperature, humidity, they will change the hardening conditions of the mixture, and the wall will crack.
  3. If moisture gets on and under the plaster during work, it may crack.

What to do?

The cement-based plaster needs to be thoroughly cleaned off and reapplied if it has come off the aerated concrete.

The constant changes in humidity can cause the plaster to come off. You must identify and address the cause of the humidity rise or fall.

If the old composition or low-quality mixture caused this, the only thing you can do is fully remove the old finish and apply a fresh one.

You should investigate the issue thoroughly. It’s possible that subsidence caused the issue, which surfaced as a result of failing to adhere to the manufacturer’s recommended plaster preparation time. Then simply start over.

It’s important to take your time drying the walls when applying the mixture in the heat. They are periodically moistened to accomplish this.

However, if cracks do show up, gypsum dough or a solution is applied to the walls. If the gaps are too big, plaster is applied after they are widened, cleaned, and moistened.

Try applying paper tape to the plaster peeling area. You will have to begin the entire task over if the tape breaks.

Plaster crack sealing has a unique algorithm of operations that includes some subtleties that need to be thoroughly examined.

The subtleties of caulking gaps:

  1. It is advised to buy a mixture of the same brand that was used previously.
  2. Do not work at air temperatures below +5°C and at humidity more than 80%.

What to do if the wall cracks again?

  • Cracked cement plaster needs to be carefully but thoroughly cleaned using a hammer and chisel. Any area that looks unsafe should be cleaned.
  • Then thoroughly rinse the crack to remove any remaining material, dirt, or dust. Wait until everything is completely dry. At the same time, you can prepare the solution. Before application, the crack should be moistened from the inside and covered with a new solution.
  • Next, attach the reinforced paper tape and wait and see what happens.
  • Then you can plaster the tape. Afterwards it should be sanded, and then the final finishing should be done.
  • A crack that is less than 5 mm wide is covered with assembly adhesive before applying the finishing putty.

If the source of the cracks has been found and removed, how can numerous tiny cracks on the surface of a wall be sealed?

Sealing every crack is the first step, after which the reinforced mesh is attached. Sealants can be used, but they need to be suitable enough to be applied to limestone walls.

If the wall is composed of concrete, the internal crack must first be lubricated with PVA glue before being covered with a cement mixture.

Why does plaster fall off the wall after repairs

After repairs, plaster comes loose from the wall because the plastering technique was not followed.

Prepare the mixture precisely as directed by mixing it well. If all went according to plan, you would require 20 kg of sand-cement composition or 9 kg of composition based on gypsum for each 1 cm layer covering 1 m². Using a clean tool, you must mix the composition in clean buckets.

How should a mixture consisting of cement and gypsum be prepared correctly?

  1. If you are making a gypsum composition, then the entire composition is slowly poured from the bag into cold water, wait a little while, and then mixed again. Do not mix old and new compositions.
  2. If you pour a lot of water into the sand-cement mixture, it will eventually shrink a lot, which will lead to cracks in the wall.

If the wall swells at the site of the crack

Moreover, the plaster could peel off. This occurs as a result of the surface being overly dry when the solution was applied. Alternatively, this solution was used in conjunction with a weaker solution. You should clean the peeling plaster off the wall, moisten the wall, and then reapply the plaster to rectify the situation.

Remember to thoroughly inspect the wall and determine any additional areas where the material may peel off before beginning any work. Remember that the strength of the solution should change in decreasing order when you create it and spread it on the wall. In other words, the plaster should be stronger at the beginning than it gets later.

Additionally, plastering over an overly damp wall can cause swelling. You should remove the material, dry the surface, and reapply the solution to make things right.

Tips and recommendations

When puttying walls, you should abide by the following advice and suggestions:

  1. Before applying the putty, you should wet the wall with plain water. This can be done with a spray bottle.
  2. The temperature in the apartment should be less than +24°C, but more than +5°C.
  3. The wall should not be exposed to direct sunlight or drafts.
  4. The solution in a layer of more than 2 cm should be fixed with beacons.
  5. Before applying the next layer, you should carefully inspect the previous layer so that there are no cracks on the wall.
  6. Gypsum-based plaster is applied in a layer that is less than 1.5 cm, and cement-based plaster in a layer less than 2 cm.
  7. We must not forget that on brick, concrete, stone surfaces, plaster is spread in a layer less than 0.5 cm, and on wood – less than 0.9 cm.
  8. You need to read the instructions written on the bag of dry plaster.
  9. The components should be mixed, observing a certain order.
  10. The walls are reinforced.

You must carefully adhere to the plaster application technology in order to avoid future wall cracks. Keep the room free from drafts and direct sunlight.

If cracks do show up, they must be cleaned and the walls must be painted again.

Problem Solution
Plaster detaching due to poor surface preparation Remove loose plaster, clean the surface, apply a bonding agent, and patch the area with new plaster
Cracks from settling or structural movement Fill cracks with flexible filler, then sand and repaint; if cracks are severe, consult a professional
Excess moisture causing plaster to fall off Identify and fix the moisture source, allow the area to dry completely, then repair the plaster

Plaster that has cracked or come off can be difficult to deal with, especially after making repairs. These problems are typically primarily caused by improper plaster application, improper material selection, or inadequate surface preparation. Over time, structural changes or issues with moisture can also seriously harm plaster.

It may not be necessary to start over with fresh puttying if you see tiny cracks or small sections of plaster peeling off. Patching these flaws carefully can solve them in many cases. You don’t need to completely redo the plastering to restore the surface; all you need to do is clean the damaged area, apply a primer that works, and use the appropriate filler.

On the other hand, extensive or widespread damage could indicate more serious problems that need more involved repairs. In these situations, the most long-lasting course of action may involve treating the underlying cause and applying a fresh coat of plaster. When choosing the best course of action, always take into account the particular circumstances of your wall as well as the degree of the damage.

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Veronica Gerasimova

Interior designer, author of books on the design of residential premises. I will help you make your home not only functional, but also beautiful.

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