There are various reasons, such as a new building or a renovation, that make plastering of interior and exterior walls necessary. Many do-it-yourselfers shy away from this because the application of new plaster sounds difficult at first. But the fear is unfounded, with simple instructions you can plaster your walls and facades yourself in no time at all.
With precise instructions, it is no longer a problem to plaster walls yourself so that they are ready for the further processing of decorative plaster, wallpaper and paint. The plaster is the most important basis and must be applied evenly, a little manual skill makes the work much easier. But it’s not nearly as difficult as you might think – every homeowner can learn plastering in just a few steps. There is not much difference between exterior and interior plastering, only the material differs. While some plasters are suitable for both indoor and outdoor use, there are specific materials that can only be used indoors. With the right plaster, however, the walls can be plastered and finished in no time at all.
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materials and preparation
Your shopping list:
- suitable plaster
- Plaster and corner profiles
- throwing blade
- Trowel and smoothing trowel
- cover film
- Painter’s Puff (optional)
- mixing bucket and water
- Primer (for concrete or old plaster)
- Drill with mixing paddle
If you have decided to apply plaster yourself inside or outside, some preparation is required. First of all, it is important to decide what role the plaster should play in the future. If it is intended to serve as a substrate and wallpaper or paint is to adhere to it, the surface structure only has to be quite large. However, if the plaster is intended as a permanent surface, a fine structure is recommended. You can achieve this through your application technique. Whether outside or inside, the instructions for applying plaster are almost identical, only the material is different.
Plaster outdoors is usually applied as visible wall protection, but it does not only fulfill optical purposes. Outside, the plaster also serves as thermal insulation and protection against weather and rain. It is therefore very important that you use a suitable plaster for a wall outside. Indoors, the demands on the plaster are lower, it is not exposed to such strong weather influences as on an outside wall. However, there is also plaster that is equally suitable for inside and outside. These products are ideal if you want to plaster a surface in both areas.
Prepare and cover work area
Before you start plastering indoors, you must carefully cover furniture and floors. Since a throwing technique is used when applying plaster, it often creates dirt that is difficult to remove. Careful coverage saves you from annoying cleaning work. When working, be sure to wear old clothes or a protective suit, because you too will come into contact with the plaster. Light switches, sockets or outside roller shutter boxes must be protected with masking tape and masking film.
Not every surface is equally suitable for receiving plaster. Walls that are too dry or too damp ensure that the plaster cannot adhere properly. However, with a little guide you can test the condition of the walls yourself. It is very important that the wall surface is free of dirt and dust. A layer of grease also means that the plaster cannot adhere properly. Depending on the substrate, a previous priming with, for example, deep primer may be necessary.
Wall test in four steps
1) Visual diagnosis:
Superficial defects that make it impossible to apply plaster immediately can be seen with the naked eye. These include large cracks, crumbling areas or existing mold. Remove all loose parts and dirt before priming/plastering. Existing mold must be treated with suitable means, otherwise it can spread under the plaster.
2) Scratch test and wipe check
If the surface chalks, it is also not suitable for plastering immediately. You can easily recognize a chalking surface. Take a pointed object, such as a box cutter, and carve a grid into the wall. Now wipe your hand over it and look at your palm. If nothing got stuck, the plaster can be applied. If, on the other hand, your hand is full of chalk, the surface must be pre-treated.
3) The adhesive tape check
You can easily test whether your walls are actually free of dirt using conventional adhesive tape. Please take an adhesive tape from the hardware store, not a craft adhesive film, as this is too weak. Press the strip of tape firmly onto the surface and then pull it off with a jerk. If residues stick to the belt, the surface is not yet clean enough.
4) The water
check You can use a simple water check to check whether the walls are highly absorbent. Fill a flower sprayer with water and lightly spray an area of about one square meter. If the drops remain on the surface, the surface is not very absorbent. If the water is immediately soaked up, the subsoil absorbs very strongly. Ideally, the water is slowly absorbed from the surface.
Clean and putty
Before you start applying plaster to the walls, you need to do some cleaning. First check the substrate for damage, such as dowel holes or cracks. These need to be repaired. For this purpose, commercially available filler must be mixed according to the instructions on the package. You must carefully apply this to the damaged areas and smooth them out. Allow the filler to dry thoroughly (observe package insert). Only when all cracks and holes have been repaired can you start plastering.
To clean, take a long-handled broom and sweep the walls thoroughly. A hand brush or a vacuum cleaner can be used in the corners. Grease stains must be removed with a detergent solution before treatment. Dishwashing liquid is ideal for removing grease residues that would make it difficult for the plaster to adhere.
The plaster must be mixed exactly according to the manufacturer’s instructions. Small amounts of plaster can be stirred with a cooking spoon, for larger amounts a whisk is essential. Place this on your drill press and stir the plaster evenly at a moderate speed. The material can only be applied to the walls when there are no large pieces left. A 10 liter building material bucket or a large tub is suitable for mixing, depending on the amount of plaster required.
In order to create the smoothest possible plaster level, corner and wall profiles must be set. These serve as a guide for the thickness of the plaster layer and ensure that the result is smooth and even. First attach the corner profiles. To do this, apply the prepared plaster at a distance of 50 cm. along the edge in small chunks. Use a spirit level and a straightedge to carefully press the corner profile. Plaster that oozes out must be smoothed out immediately with a trowel so that there are no bumps. First place all the corner profiles before you start laying the wall profiles.
With the plaster profiles you have to make sure that they are exactly vertical, so the spirit level is indispensable. Attach the plaster profiles to the walls at a distance of approx. 1.5 meters. The profiles remain on the wall, they do not have to be removed again. As with the corner profiles, the plaster battens are attached to the wall with some plaster and pressed firmly. You can now see from the batten depth how deep your plaster layer may be on the walls.
Whether you need a primer depends on the condition of the wall. However, it is advisable to apply a primer instead of having problems with the distribution of the plaster afterwards. If the previous wall test showed that you want to treat very absorbent walls, you must wet them well with water before applying the plaster. This prevents the liquid in the plaster from being absorbed too quickly by the wall. A paint brush is a good tool for spreading water on the walls.
If the walls to be treated are drywall panels, old plaster layers or concrete, a primer is generally recommended. Prepare the primer according to the instructions on the packaging and spread it generously and evenly over the walls with a roller. It is important that the primer is completely dry before you start plastering.
Plaster is applied to the walls inside and outside in two layers. Start with the base layer. You apply this with a throwing technique that you can easily teach yourself. Pick up a medium amount of plaster on your trowel and then throw it at the wall with your wrist. Whenever you have plastered an area of two square meters, smooth the mass with a smoothing trowel. The first layer of plaster should be about one centimeter thick. Continue this technique until the entire area has been plastered and then allow the plaster to dry thoroughly according to package directions.
Before you start applying the second layer, you must moisten the first layer of plaster well again with the painter’s brush. Please check again beforehand whether the first layer has really dried through. Humid ambient air can cause the time stated on the packaging to be longer. When plastering walls outside, it should be noted that the ambient temperature should not be below five and above 30 degrees.
The second layer of plaster is no longer thrown at the walls, but applied directly with a smoothing trowel. Pick up a medium amount of plaster with the trowel and spread it over the surface. Always work in sweeping movements from side to side, never criss-cross. How thick the second plaster layer should be depends on the profile of the plaster battens, but it should not be more than ten millimeters.
Regardless of whether you are plastering walls on the inside or outside, the work steps are identical. Bring the second layer of plaster completely to the walls before you start smoothing. To do this, take the grapeshot and smooth the plaster. Start working on the left side of the wall and then work your way from top to bottom and from left to right step by step. Work quickly and without breaks so that the plaster does not dry in the meantime and ridges remain visible.
Tip: If you have decided on textured plaster, the last step is not carried out with the grapevine, but with a float. This is suitable for bringing structures into the plaster on the walls.
Tips for speed readers
- Select plaster depending on the place of application
- Examine the wall for texture
- Repair existing defects and cracks
- Check the absorbency of the wall
- Clean the wall inside and out
- Check the cleanliness of the wall
- Mix the plaster exactly according to the instructions
- If necessary, moisten or prime the wall
- Allow the primer to dry thoroughly
- Attach corner and plaster profiles exactly
- apply first layer of plaster with throwing technique
- flatten and let dry well
- Apply second layer of plaster with a smoothing trowel
- In the case of textured plaster, smooth with a float
- With normal plaster, smooth out with a canister