Plaster aerated concrete - what do you have to pay attention to?

The material properties and the granular structure of aerated concrete can cause problems when plastering. Not all plaster types are suitable for aerated concrete, and there are other things that need to be considered. Which materials are suitable and how to proceed, is shown in the following detailed step by step instructions.

Material properties of aerated concrete

Aerated concrete has a very light, porous structure. The numerous air pockets (pores) ensure that the weight of the aerated concrete block remains very low, but also that aerated concrete blocks can absorb a great deal of water. The adhesion of plaster is thereby adversely affected.

The friable structure can also easily lead to damage to the porous concrete block occur. Before plastering, all damaged areas must be repaired.

Plaster aerated concrete - what do you have to pay attention to?: plaster

When repairing it is necessary to use a so-called stable filler. It must also be demonstrably suitable according to the package specification for aerated concrete. Repair mortar is also available for aerated concrete.

Plaster finish indoors

The plaster version is best done in two layers inside. Above the flush is still attached a top coat.

Gypsum plasters, which adhere better to the aerated concrete, are particularly suitable for flush-mounting. There are no restrictions for the finishing plaster.

thin plasters

Thin-film plasters can only be used on non-load-bearing walls indoors. There, layer thicknesses between 3 and 5 millimeters are possible.

Exterior plaster on aerated concrete

Outside, lightweight mineral plasters are used, which can be applied in one or two layers. Thin-film plasters are also possible in exceptional cases, but this is always dependent on the individual case. Here you should always seek the advice of a trusted professional.

Special emphasis should be placed on outdoor weatherproofing and waterproofness. He must also be impermeable and stretchy. This already limits the selection of possible plasters significantly.

In some cases splashing may be necessary for better adhesion. A plaster reinforcement is mandatory at the transition to other building materials.

Interior plaster with aerated concrete step by step

  • aerated concrete wall
  • Plaster plaster as a concealed plaster
  • Finishing plaster (optional)
  • putty
  • adhesive paint
  • Cleaning trowel, trowel
  • mop bucket
  • Drilling machine and agitator or alternatives

1. Check the plastering surface

First, check the plaster base for damage and repair with filler (stable and suitable for aerated concrete). Fill all open joints.

The wall must be free from contamination, clean and free of grease. Then apply a coat of adhesive.

2. plaster rails and Purzarmierung

Install reinforcement in the transition area to other building materials to avoid cracks. Install plaster rails at a distance of approx. 50 cm.

3. Flush

Apply plaster and remove cleanly along the attached plaster rails. Ensure even adhesion of the plaster. Then cure as specified by the plaster manufacturer.

4th surface plaster

Apply top coat to the hardened flush.

Tips & Tricks

It does not always have to be plastered. Non-load-bearing walls can also be sanded, primed and simply painted with a vapor-permeable paint. Gluing ceramic tiles with special glue directly onto the straight wall can also be a way to avoid plastering.

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