Grinding screed - That's how it's done!

You can often do the screed grinding yourself

Difficulty: Medium | Costs for 100 m²: approx. 300 euros | Workload for 100 m²: approx. 8 hours

In Germany and Austria, the term screed refers to the level subsurface required for the construction of floors. In Switzerland this is called Unterlagsboden. This serves as a connecting layer between the unfinished floors and floor coverings such as tiles, carpets or parquet. This article provides you with all the information you need to know about "grinding screed".

Figure 1: Do the grinding of screed yourself with this guide

1. When do I have to grind screed?

The grinding of screed is always used when rough surfaces are present and these need to be processed. This can be divided into two groups:

1.1 Grinding screed in new buildings:

With a new screed, the pre-treatment by grinding the screed plays an important role. Careful preparatory work determines good adhesion between the floor covering and the screed. The focus should be on a flat, smooth and clean surface.

1.2 Grinding screed during renovation/restoration work:

With an old screed, unevenness caused by residual materials such as adhesive or mortar may remain after the old floor covering has been removed . These must be sanded down before laying the new floor in order to be able to achieve successful results with the finished surface when laying the new floor.

2. How do I grind down screed?

 

In order to be able to start sanding screed, you should prepare yourself for certain points in advance. These points include the necessary protective equipment and tools or machines to ensure good, solid work.

2.1 What do I need to grind screed?

Due to the high dust development caused by grinding screed, certain protective equipment is required in order not to endanger your own health. This includes a protective suit, work gloves, respirator mask, safety goggles and hearing protection.

You should also think in advance which machines will be needed for your work. It is advisable to use a diamond rotary disc or a floor grinder or drywall sander for sanding down large areas. In addition, you should have an industrial vacuum ready to thoroughly vacuum off the removed material. Alternatively, an angle grinder equipped with a diamond cup wheel can be used for surfaces that cannot be reached with a diamond rotary disc or floor grinder or a drywall grinder.

Buy the diamond cup wheel for the angle grinder for screed grinding here.

In addition, you will find a detailed description of how to grind screed using an angle grinder in our blog " Grinding screed - angle grinder" - Click here for the blog.

2.2 What grit do I need for grinding/polishing the screed?

Which grit is required for grinding the screed depends on the planned floor type. If you want to use the screed as a fair-faced screed, a finer grain size should be used.

The very smooth surface of the exposed screed gives the living room a stylish look.

However, if the screed is used as a substrate for tiles, for example, the screed should be sanded with a 16 grit. Sanding the screed improves adhesion between the substrate and the tiles.

2.3 How much does screed grinding cost?

The cost of grinding screed depends on the area to be processed. Whether you take the project into your own hands or have the upcoming work done by a professional craftsman also influences the amount of the costs.

If you dare to do the work yourself, you could face costs of around 290 euros - 330 euros for an area of ​​100m² (8 hours of work):

Personal protective equipment (approx. 31 - 50 euros):

• Protective suit approx. 3 – 5 euros
• Work gloves approx. 1 – 2 euros
• Respirator mask approx. 20 – 30 euros
• Safety goggles approx. 1 – 3 euros
• Hearing protection approx. 6 – 10 euros

Machine rental from a hardware store (approx. 160 euros):

• Angle grinder approx. 12 euros (daily rate)
• Concrete grinding machine approx. 110 euros (daily rate)
• Industrial vacuum approx. 38 euros (daily rate)

Tools (approx. 99.90 euros – 119.90 euros):

• Sandpaper set 10 pieces approx. 15 euros
• Diamond cup wheel 125 mm iynx Tools 24.90 euros
• Synthetic resin / epoxy resin for sealing (10 liters) approx. 50 - 70 euros
• Brush and roller about 10 euros
  

Prices are from current internet research (11/12/2022).

2.4 Screed grinding costs per square meter

method	Costs
angle grinder	from €19.90
concrete grinder	from €34.90
drywall sander	Rent from €110.00 per day
screed cutter	rent from €135.00 per day

3. Grind and seal the screed - step-by-step instructions

Grinding and sealing screed can usually be carried out successfully even by people with little experience by observing the respective steps. The grinding and sealing of the screed is divided into three steps. These are grinding, vacuuming and optional sealing for fair-faced screed.

Figure 2: Sanding the screed – do it yourself!

1. Take care of occupational safety before starting your upcoming work. You should put on a breathing mask and safety goggles because of the dust that is generated during sanding. In addition, your hearing should be protected with hearing protection.

2. First clean the surface to be treated with an industrial vacuum cleaner. Be careful to ensure the floor is free of loose debris before sanding. Large loose material residues could scratch deep grooves in the screed during the grinding process.

3. Equip the floor grinder with the appropriate sandpaper for your application and start the floor grinder. Important: When using the sandpaper for the first time, pay attention to the increased frictional resistance of the sandpaper, which can affect the floor sander.

4. Sand the surfaces evenly using the floor sander. Care should be taken to keep the handle of the floor grinder flat. This ensures better gliding of the floor grinder on the screed. Check the sandpaper after certain time intervals and change it if necessary to prevent the sandpaper from wearing through.

5. If you can't get to all parts of the room with the floor grinder, then you should use the angle grinder. In combination with the right diamond cup wheel, the angle grinder is a good alternative for working on surfaces such as corners or stairs.

6. After the room has been completely sanded, the increased occurrence of dust must be counteracted by cleaning with an industrial vacuum cleaner. You should make sure that before each new grinding process, the surface to be processed must be free of particles in the form of dust or material residues from the previous grinding process.

7. Repeat steps 4 to 6 until the desired grinding result is achieved.

8. Screed - If your project involves installing new flooring such as carpet or tile, once you have cleaned the surface, you can begin installing the new floor

8.1 Fair-faced screed - However, if your project involves fair-faced screed, it is imperative to seal the sanded surface promptly due to the sensitive and porous surface. Synthetic resin or epoxy resin, for example, are suitable for this, which you can buy as ready-made sets in hardware stores.

9. Mix the sealing medium (e.g. synthetic resin or epoxy resin) thoroughly and apply to the fair-faced screed with a brush or roller. You should make sure to apply thin and even layers. Usually at least two jobs are required to get a good result. The drying time before walking is approx. 24 hours. Complete drying of the seal is achieved after 72 hours. Good ventilation and a minimum temperature of 5°C are required while the seal is drying. Direct sunlight should also be avoided during drying.

We hope the information was able to help you. We look forward to a comment as to whether the article helped you.
If you have any questions, you can contact us at any time.

Frequently asked questions about grinding screed