High-pressure cleaners are among the inconspicuous yet indispensable auxiliaries in construction, dismantling and stone processing. They remove concrete dust, drill slurry, formwork oils, sludges and corrosion products, prepare surfaces, and keep tools as well as work environments operationally reliable. In combination with hydraulic demolition and cutting tools from Darda GmbH—such as concrete pulverizer, stone and concrete splitter, steel shear, combi shears, or tank cutters—they improve workflows and outcomes in concrete demolition and special dismantling, in building gutting and cutting, in rock breakout and tunnel construction, in natural stone extraction as well as during special demolition assignments.
Definition: What is meant by high-pressure cleaners
A high-pressure cleaner is a device for water-jet cleaning. A pump increases the water pressure and forces the medium through a nozzle. This creates a directed jet that detaches dirt and deposits from surfaces. Technically decisive are pressure (bar), flow rate (l/min), water temperature (cold or hot water), and nozzle geometry. Classical high-pressure cleaning often operates in the range of about 80 to 250 bar, industrially also above. Distinct from this is ultra-high pressure (UHP), which reaches into the range of several thousand bar and is used for hydrodemolition or precise material removal. In the context of concrete demolition and stone processing, high-pressure cleaning primarily serves cleaning, surface preparation and site efficiency—it is not a cutting or splitting technique in the narrow sense.
Technical key data: Pressure, flow rate and temperature
The selection of a high-pressure cleaner depends on the material, contamination and objective (cleaning, preparation, removal). Essential parameters determine the effect and the degree of material friendliness.
Pressure and energy density
As pressure increases, the jet’s impulse density rises. Concrete dust, cement slurries and light efflorescence can often be removed already at 120–180 bar. Heavy incrustations or bitumen and paint deposits sometimes require significantly more pressure or a different nozzle. On mineral substrates the balance is important: excessive point pressure can mill edges or damage the mortar matrix.
Flow rate and area performance
The liter output per minute determines how much energy and flushing volume arrives. Higher flow rates increase area performance and reliably flush detached particles from cracks, boreholes and joints—important when working with stone and concrete splitter and stone splitting cylinders, because clean boreholes stabilize the splitting effect.
Hot water or cold water
Hot water accelerates the dissolution of fats, formwork oils and organic deposits and thus increases cleaning quality. Cold water is usually sufficient for mineral dusts and drillings. With reinforcement and steel parts, warm water can shorten drying, which facilitates subsequent steps (e.g., cutting with steel shear or corrosion protection).
Drive and power supply
Electric units operate emission-free at the point of use and are advantageous indoors and during building gutting. Combustion variants deliver high performance outdoors. In tunnel construction and special demolition assignments, exhaust management and ventilation play a role. Coordination with the hydraulic power pack and the rest of the construction logistics creates synergies.
Spray pattern and nozzles: Steering the effect precisely
The nozzle determines impact area and removal behavior. The spray pattern is adapted to the substrate and the work purpose.
Fan nozzle
Flat, uniform cleaning with good control. Suitable for concrete surfaces, natural stone blocks and steel plates when homogeneous, material-friendly treatment is desired.
Rotary nozzle (turbo nozzle)
Rotating point jet with high energy density for stubborn deposits, cement slurries and efflorescence. Use caution at edges or on sensitive natural stones to avoid micro-damage.
Point and needle jet
Highly concentrated for local deposits, e.g., in cracks, notches and boreholes. Suitable for targeted preparation prior to using concrete pulverizer or setting splitting tools.
Applications in demolition and construction: Interfaces with concrete pulverizers and stone and concrete splitters
High-pressure cleaners are no substitute for hydraulic separating or splitting technology, but they directly support it. They increase process reliability, improve surface quality and reduce rework. Typical interfaces involve preparation, intermediate cleaning and finishing.
Concrete demolition and special dismantling with concrete pulverizers
Concrete pulverizers break components in a controlled manner. The water jet then removes loose mortar particles, concrete fines and rust products. This facilitates exposing and assessing the reinforcement and creates clean starting points for steel shear, combi shears or Multi Cutters. Follow-up work on the remaining cross-section benefits from cleaned contact surfaces, for example before applying corrosion protection or installing strengthening elements.
Stone and concrete splitter as well as stone splitting cylinders
Boreholes must be free of drill dust so that split wedges and stone splitting cylinders can grip optimally. A targeted water jet flushes the hole, removes smear layers and increases the reproducibility of the splitting line. Visual inspection of incipient cracks on natural stone is also easier on clean surfaces, which increases accuracy in natural stone extraction.
Steel shear, combi shears and Multi Cutters
Prior to cutting, cleaned steel surfaces improve positioning and visibility. Paint, bitumen or mortar residues can—within the scope of permissible procedures—be removed with suitable nozzles. After cutting, the high-pressure cleaner frees components and work zones from chips and sludge, accelerating subsequent work.
Tank cutters and special assignment
When working on tanks and vessels, removing residues can contribute to safety. High-pressure cleaning can mechanically loosen organic deposits. Material properties, emissions and possible aerosol formation must be carefully assessed. Planning follows the regulations in force and the approved work procedure.
Rock breakout and tunnel construction
Dust-binding cleaning after the use of chiseling or splitting technology ensures a clear view of cracks, joint surfaces and drilling patterns. Mesh reinforcement, anchor plates and formwork areas are water-jet cleaned before further steps (e.g., sealing, coating). In tunnels, water routing, settling basins and sludge handling gain particular importance.
Hydrodemolition and mechanical demolition: Distinction and interplay
Hydrodemolition with UHP water jets is suitable for selectively removing concrete and exposing reinforcement without introducing delamination. Mechanical methods—such as with concrete pulverizer—impress with high removal performance, mobility and low media logistics. In practice they complement each other: mechanically pre-break in the rough, then remove selectively with water jets, or vice versa. The decision depends on component thickness, reinforcement density, boundary conditions (noise, vibration) and the required surface roughness.
Surface preparation for improved adhesion and protection systems
Clean, grippy surfaces are the basis for coatings, repair mortars, bonding and corrosion protection. High-pressure cleaners remove cement slurries, salt crusts and binder residues and produce a defined roughness profile. After breaking with concrete pulverizer or splitting with stone and concrete splitter, edges, bed joints and bearings are freed from loose particles by the water jet. This reduces defects in subsequent layers.
Water and sludge management
Concrete and rock removal generate alkaline sludges and fines. Wastewater should be routed through settling stretches, filters or separators. pH neutralization may be required. Indoors, suction devices and controlled water routing reduce the spread of moisture. Disposal is generally subject to local requirements; discharges without treatment are usually to be avoided.
Occupational safety in high-pressure cleaning
Water jets pose injury risks, including injections into the skin. Jet deflection, rebound and aerosols must be taken into account. Tailored protection and work organization are mandatory.
- Personal protective equipment: safety glasses/visor, gloves, slip-resistant clothing, hearing protection, safety footwear.
- Equipment safety: pressure test, hose restraints, functioning shut-off, visually checked couplings.
- Work environment: cordon off the jet area, secure standing surfaces, orderly hose routing.
- Material protection: choose distance and nozzle so that surfaces are not unintentionally damaged.
- Qualifications: instruction in equipment and procedure, emergency concept, first aid for high-pressure injuries.
Equipment care: High-pressure cleaners and hydraulic tools
High-pressure cleaning keeps tools and the hydraulic power pack clean externally but must not stress sensitive components. Seals, bearing zones and electrical connections on the equipment from Darda GmbH should not be directly subjected to a concentrated jet. After cleaning, drying and a light corrosion-protection film on steel surfaces are sensible. Hoses, couplings and valves are checked for moisture, dirt and potential damage.
Selection and sizing for construction, dismantling and natural stone
The optimal equipment configuration depends on the task, substrate and workflow planning. A structured selection prevents over- or under-sizing.
- Define the task: remove dust, strip sludges, dissolve oil, flush boreholes, roughen surfaces.
- Determine the substrate: concrete strength, aggregates, natural stone type, steel grade and coating.
- Select performance data: pressure and flow rate suited to the task; plan reserves for stubborn areas.
- Nozzle and accessories: fan jet for areas, rotary nozzle for stubborn zones, point jet for joints/boreholes; lance and extension for ergonomics.
- Water temperature: hot water for oil/fat/bitumen, cold water for mineral particles.
- Logistics: water supply and disposal, settling volume, electric or fuel supply, process reliability.
- Plan interfaces: define the sequence with concrete pulverizer, stone and concrete splitter, steel shear, combi shears, Multi Cutters and tank cutters.
Typical workflows in dismantling
Sequences with high-pressure cleaning increase quality and order on the construction site. They reduce downtime and improve visual inspection.
- Preparation: coarse cleaning of the surface, apply markings on a clean substrate.
- Mechanical intervention: use concrete pulverizers or stone and concrete splitter; fracture edges are created in a controlled manner.
- Intermediate cleaning: expose boreholes, cracks and contact surfaces with a water jet; check splitting and cutting interfaces.
- Further processing: cutting with steel shear, combi shears or Multi Cutters; if necessary, selective removal.
- Finish: wash surfaces, collect sludges, prepare corrosion protection and surface treatment.
Avoiding common mistakes
- Excessive point pressure at edges leads to spalling; better use a fan jet and vary distance.
- Only “wetting” boreholes instead of flushing: residual dust impairs splitting effect and measurement accuracy.
- Undesired water ingress into cavities: plan water routing and suction.
- Direct jet on bearings, seals and electrical components: protect sensitive zones.
- Insufficient sludge treatment: provide settling and filter stretches and maintain them regularly.
Standards, guidelines and permits
Different requirements apply to high-pressure work depending on country and federal state, for example regarding occupational safety, noise, wastewater and waste. With hydrodemolition, additional sets of rules may be relevant. Permits and notifications must be clarified case by case with the competent authorities. The notes are general and do not constitute legal advice.
Terminology and distinction from water jet cutting
High-pressure cleaning serves cleaning and preparation. Water jet cutting—usually with abrasive—uses extreme pressure and focused nozzles for separation. In practice there are transitions, for example with selective concrete removal. In combination with the products of Darda GmbH, however, the focus is on cleaning, making structures visible, and increasing process stability during breaking, splitting and cutting.