Guide » Drilling reinforced concrete - That's how it's done!

Drilling reinforced concrete - tips & tricks

Difficulty: Easy | Costs: dependent on drilling depth, drilling, etc. | Workload: depends on drilling depth, drilling, etc.

Reinforced concrete is a composite building material consisting of concrete and reinforcing steel. It is often used in construction and offers advantages over conventional concrete due to its high compressive and tensile strength. However, challenges are often encountered when drilling in reinforced concrete, as this material is particularly hard and resistant. In this article you will learn which equipment you need, which techniques you should use and which tips and tricks can help you when drilling in reinforced concrete. This makes drilling in reinforced concrete easy and safe.

1. The right equipment for drilling in reinforced concrete

In order to be able to drill in reinforced concrete, you need the right equipment. This includes a powerful hammer drill, suitable concrete drill bits and suitable protective clothing:

1.1. rotary hammer

A powerful hammer drill is required for drilling in reinforced concrete to penetrate the hard material combination of concrete and rebar. The power is usually given in watts, and for drilling in reinforced concrete a device with at least 800 watts should be selected. The higher the power, the more effective and faster you can drill. Also make sure that the hammer drill has an impact drill function, which can also be referred to as a "hammer drill function". A hammer drill function is essential for drilling in reinforced concrete as it provides the necessary force to effectively penetrate the material.

1.2. concrete drill

Drilling in reinforced concrete requires special concrete drill bits with hard metal tips , also known as widia or tungsten carbide tips . These are particularly resistant and enable a clean and precise drill hole. Make sure the concrete drill has an SDS Plus or SDS Max shank that is compatible with your hammer drill. These mounting systems enable the drill bit to be changed quickly and easily and ensure a firm hold in the hammer drill.

1.3. safety goggles and hearing protection

Drilling in reinforced concrete creates a lot of dust and noise. Therefore, wearing the correct protective equipment is crucial for safety and health when drilling in reinforced concrete. Important protective equipment includes:

• ear protection
• eye protection
• respiratory protection
• Gloves
• safety shoes

2. Drilling techniques for reinforced concrete

In order to be able to successfully drill in reinforced concrete, you should learn and use a few basic techniques. This includes marking and center punching, percussion drilling and checking the drilling depth.

2.1. Marking and center punching

Before you start drilling, you should precisely mark and center punch the drilling locations. To do this, mark the desired drill holes with a pencil or a suitable marking pen. Then punch the spots with a center punch or a pointed object to prevent the drill from slipping. Note that drilling rebar can affect the structure of the concrete and its bearing capacity. Therefore, the drilling position should be checked in advance with a rebar or metal detector in order to avoid rebar as much as possible or to keep the number of holes to a minimum.

2.2. impact drilling

When drilling in reinforced concrete, the impact drilling function of the rotary hammer is indispensable. It ensures that the drill also gets through the hard reinforced concrete. Make sure to always keep the drill straight and perpendicular to the wall to get a clean and accurate drill hole.

2.3. Check drilling depth

To maintain the correct drilling depth, you can use the depth stop on the hammer drill or mark the drilling depth with a tape measure or a piece of tape on the drill. This will prevent you from drilling too deep or too shallow.

3. Tips and tricks for drilling in reinforced concrete

A few tips and tricks can help you achieve even better results when drilling in reinforced concrete:

3.1. The right speed

Pay attention to the right speed when drilling in reinforced concrete. Too high a speed can overheat and wear out the concrete bit, while too low a speed makes drilling difficult. In general, the speed should be reduced when using larger drills, while a higher speed is appropriate for smaller drills.

Here are some RPM guidelines for drilling in reinforced concrete:

• For drills with a diameter of 4-8 mm: about 900-1200 rpm
• For drills with a diameter of 10-14 mm: about 700-900 rpm
• For drills with a diameter of 16-20 mm: about 500-700 rpm

However, it is important to note that the optimal speed also depends on the power and settings of the hammer drill. Some rotary hammers have a speed control that allows the speed to be adjusted according to the needs of the job at hand. Start at a lower speed and gradually increase it until efficient drilling performance is achieved without overloading the material or damaging the bit.

Make sure to always use the hammer drill mode during the drilling process as it is specially designed for drilling in hard materials like reinforced concrete. The impact drilling mode works independently of the speed and ensures effective destruction of the concrete and fast drilling progress.

3.2. cooling and lubrication

To prevent the concrete drill from overheating, you should regularly pull it out of the drill hole and let it cool down. In some applications, especially when using diamond core bits , it can be useful to use water as a coolant. Water reduces friction and the heat generated, while at the same time binding the concrete dust. In such cases, it is important to use an appropriate water supply, such as a water supply drill or a water container with a hose.

3.3. Pay attention to the resistance

If you encounter increased resistance when drilling into reinforced concrete, this can be an indication of rebar in the concrete. In this case, you should stop drilling and choose an alternative drilling location to avoid damaging the reinforcement and the drill. Therefore, try to determine the position of the reinforcing bars in the reinforced concrete before drilling. You can use a rebar or metal detector for this. This may allow you to choose a drill location that doesn't directly hit a rebar.

3.4. clean the borehole

While drilling, you should regularly pull the concrete drill out of the drill hole to remove the drilling dust and prevent the drill from overheating. This also improves the lubrication between the concrete drill and the borehole wall. After drilling, you should clean the drill hole thoroughly to remove dust and concrete residue. You can use a vacuum cleaner or brush to do this. A clean drill hole is important for the durability of dowels and screws.

4. Summary

Drilling in reinforced concrete is quite doable with the right equipment, the right techniques, and a few helpful tips and tricks. Be sure to use a powerful hammer drill, proper concrete drill bits, and protective clothing. Marking, center punching, impact drilling and checking the drilling depth are important techniques that you should master. In addition, correct speed, cooling and lubrication of the drill bit, paying attention to resistance and cleaning the drill hole can all help ensure that your drilling project in reinforced concrete is successful and safe.

5. Frequently Asked Questions

5.1 Can I also drill in reinforced concrete with a normal impact drill?

A hammer drill is more suitable because it has a higher impact power and can therefore get through the hard reinforced concrete more easily. A hammer drill may suffice on thin layers of concrete, but is less effective on solid reinforced concrete.

5.2 Which concrete drills are suitable for drilling in reinforced concrete?

Concrete drill bits with carbide tips are ideal for drilling in reinforced concrete. They are particularly resistant and enable a clean and precise drill hole.

5.3 How deep should I drill in reinforced concrete?

The drilling depth depends on the application, eg anchoring dowels or screws. Make sure the drilling depth is sufficient to safely support the load, but not too deep to compromise the stability of the reinforced concrete.

5.4 How do I recognize rebar when drilling in reinforced concrete?

Increased resistance when drilling can indicate rebar in the concrete. In this case, you should stop drilling and choose an alternative drilling location to avoid damaging the reinforcement and the drill.

5.5 How can I clean the drill hole after drilling?

You can clean the drill hole with a vacuum or brush to remove dust and concrete residue. A clean drill hole is important for the durability of dowels and screws.