Plaster inside walls - DIY instructions for plastering
- Properly plaster the interior walls
- Mix plaster
- Wet the wall
- Plaster the wall
- Second layer of plaster
- fill in
- Extra: plaster outer walls
There are a few reasons why walls need to be plastered. The most common case of renovation and new construction is the case or when pipes and pipes have been newly laid. Defects have to be repaired and the walls have to be plastered again. With a little practice, you can do this as a hobby craftsman, but there is a lot to consider. Of crucial importance is the choice of the plaster, because plaster is not the same plaster and the preparation of the substrate. Plaster in the true sense is a coating of mortar and different binders. It creates smooth surfaces, but at the same time protects the inner walls and improves the moisture regulation in the interior.
Which plaster types are differentiated ">
Hand plaster - used by hobby craftsmen most often, the ready-mixed plaster is thrown with the trowel on the wall and this mass is equal then leveled with a Abziehlatte or grape box. It is important to distribute them in a correct way. Depending on how the top coat should look like, it must then be smoothed, felted or simply straightened. The layer thickness of this plaster must be 8 to 10 mm at the end.
Thin and Spachtelputz - can be processed manually or by machine, but you need an absolutely flat surface. The layer thickness is 2 to 5 mm.
Machine plaster - Mortar is mixed in the plastering machine with plenty of water and sprayed by compressed air through a hose on the walls and ceilings. This must then be distributed manually flat with a leveling device or grape box. This layer is at least 10 mm thick.
It does not matter which plaster and which type of plaster you choose, it is important to work quickly. The wet plaster must be applied and smoothed quickly and evenly, otherwise an uneven surface is created and the projections and transitions are visible. These places must be sanded off again at the end. To plaster a wall is not very difficult, but who is meticulous and wants to have a really smooth surface, usually has to practice a little until it succeeds. If you want to, you should start with a wall in the cellar, in the utility room, in the hobby room or in the garage until you get the hang of it.
Plastering alone is very exhausting. You have to imagine it like this:
- A sack of gypsum plaster (30kg) is sufficient for a plaster thickness of 10 mm only for an area of 2.5 m², that's not much.
- For a plaster thickness of 1 mm to 1 m², 1 liter of material is needed
- For 10 m² and 10 mm thickness, this is 160 kg that has to be distributed.
- Wall trowel - to be plastered against the wall, if possible made of stainless steel, to avoid rusting in the gypsum plaster
- Trowel - to raise plaster
- Grape box (float) - for smoothing and rubbing freshly applied plaster, for greater strength and a more uniform surface
- Smaller trowels (cat tongues) for narrow areas (around windows and on door frames)
- Sponge board - for felting the plaster surface during setting
- Clay gauge - helps to apply the mass evenly, consists of strips and corner rails
- Cleaning machine (can be borrowed at the hardware store) - difficult for laymen, since it must be extremely fast
Plaster does not stop at every wall. The prerequisite is that the substrate is dry, firm and stable. That's why he needs to be examined. In a new building is usually all right, but especially in old buildings or even renovations of not so old houses you have to proceed very carefully.
If cracks, crumbly parts or mold are visible, the wall needs pretreatment. Of course, loose parts and dirt must be removed. As a test, whether the wall holds, you can apply a strong adhesive tape and then pull off this jerky again. Nothing should stick to the band itself. Depending on the damage or contamination, the wall can be cleaned with a hard broom or sandblaster . An important test is to lightly moisten the wall surface with water and observe the drops.
- If they remain, the substrate is not absorbent
- If the water dries in slowly, it is normally absorbent and ideal for plastering
- If it absorbs quickly, the surface is very absorbent
- This sample is crucial for the further procedure
- The suction behavior determines which primer has to be used
- Normal absorbent substrates only need a deep background
- Highly absorbent substrates, on the other hand, require an adhesive emulsion
All rough bumps must be removed before starting the plastering work. Soil and all surfaces that should not be plastered should be covered or covered over a large area.
If there are corners whose adjacent walls are to be plastered, corner profiles made of sheet metal are used ( outside corners, not at 90 ° angles). Place the profiles directly on the corner and apply the plaster profile mortar in small quantities at the edges. The sheet is pressed with a leveling plate. Smooth out excess and swelling mortar. The plaster must dry for at least 1 hour before it can be further worked. Apply plaster profiles, also plaster slats or cleaning strips. They serve as an orientation, how thick plaster must be applied. They remain like the corner profiles on the wall and disappear at the end completely under the plaster layer. The profiles must be exactly vertical. You choose a distance between 1 and 1.5 m.
Properly plaster the interior walls
After a good preparation, it can now go to the actual plastering. First, the plaster is mixed, then made the wall a little damp and then the first layer of plaster follows.
Mixing plaster is straightforward. What is needed is a large vessel, clean water and the actual plaster, usually in large bags or sacks. You just have to follow the instructions of the manufacturer and stir the mass according to its specifications. It is important that it is well mixed, which works best for small quantities with a large mixing spoon. For larger quantities, we recommend an electric stirrer . Drills with stirring attachment usually do not develop enough power. Often a wheelbarrow is used for mixing, which is also not recommended, because you can not well and evenly stir by the different height.
Wet the wall
If the plaster base is well prepared, which means that the possibly required primer has been applied, the wall should be wet, as the expert says. Water is simply sprayed onto the wall, preferably with a paste brush, ceiling brush or alternatively with a painter's quast. You should not stingy with water, because the wall to be plastered should be moist.
Plaster the wall
Ideal for applying the mass is a wall trowel or a spatula. With both tools, the mortar mass can be thrown against the wall. The throwing has the advantage that the mass passes through the pressure in fine scratches and grooves, which is not the case with normal application. Alternatively, a smoothing trowel can be used, with which the mortar is applied. Here is exercise is required, the throw is not easy.
- Cleaning edges and corner profiles are ideal for large plaster surfaces. They protect the edges from damage and wear.
- Quick cleaning strips are very helpful when leveling slate walls. It is mounted on the day before with a distance of approx. 1 m perpendicular and flush to the walls. When applying and removing the plaster, the strips then prevent the removal of the excess plaster from the uneven walls.
- It is important to work fast.
- Spread a complete layer over the entire wall
Second layer of plaster
If the required layer thickness has not yet been reached, the cleaning strips are still visible or individual spots have not yet been compensated, a second layer is necessary. The mortar mass is no longer thrown against the wall, but applied with the trowel and mounted on the wall. It is important to remove the protruding plaster, so deduct. It is best to use a standard or teaching.
At the very end, the wall must be filled. But it must be dry, which is only the case after a few days. The length of the drying time depends on the type of plaster and application thickness. As long as the plastered surface is still dark, that means the plaster is still very damp. The brighter it gets, the drier the surface. Only when it has dried properly, can it be sanded off and then filled with sand.
The filler must be mixed according to the manufacturer's instructions. Then it can be roughly applied with a surface spatula and then distributed all over. Always work from the bottom up and very evenly. When everything has been spackled off, peel off the wall from bottom to top and smooth it out completely. If there are still uneven spots after drying, repeat the process until the wall is smooth.
Now the wall can be painted, wallpapered or decorated with decorative plaster.
Extra: plaster outer walls
In principle, there are no major differences between the plastering of interior and exterior walls. The plasters are different, however. In the outdoor area usually machine plaster is used. This not only has visual tasks, it also protects the house facade. Although hobby craftsmen can plaster their house from the outside, but should get quite untrained yet experienced support to do so. Again, it depends on the ground. He must be clean and even. For bricks or aerated concrete, a primer with adhesive emulsion is recommended.
- Also important here is the wetting of the wall. The mineral plaster is brought to the wall in sections and distributed.
- Cleaning compound must not dry out
- No temperatures below 5 ° C and above 30 ° C
- During the entire time and the drying time protect the plastered wall from strong sunlight or driving rain.
You can plaster walls yourself, even as a hobby handyman, but it takes time and costs strength. Building a wall or a room is certainly not the problem, a whole newly built house, however, already, because that takes ages, according to experience. Experts usually only need half the time to less and their results are often more satisfying. But who really has to save, can do it himself, but should take his time. It is advisable to practice on walls that hardly anyone ever sees.