Refurbishment works cover all construction interventions on existing buildings and facilities—from building gutting and selective deconstruction to creating new openings. Unlike new builds, planning and execution must accommodate real-world boundary conditions: restricted accessibility, concurrent use during construction, unknown component qualities, noise control requirements, and strict conditions to protect neighboring buildings and users. Tools and methods therefore have to be selected with precision. In practice, low-vibration methods such as hydraulic splitting of concrete and masonry with hydraulic rock and concrete splitters, as well as targeted shear-crushing with concrete demolition shears, play a central role to separate fabric in a controlled manner and safeguard the load-bearing capacity of the remaining structure.
Definition: What is meant by refurbishment works
Refurbishment works refers to the technically and organizationally demanding planning and execution of construction services on existing buildings, infrastructure, and industrial plants. This includes, in particular, structural adaptations (e.g., wall and slab openings), refurbishments, partial demolition, building gutting, special demolition, and preparation for repurposing of structure. The approach is characteristically selective: components are separated in a targeted way, materials are segregated by type, and emissions (noise, dust, vibrations) are minimized. Hydraulic tools such as concrete demolition shears, stone and concrete splitting devices, and suitable hydraulic power packs are frequently used because they operate in a controlled, compact, and low-emission manner.
Specific characteristics and challenges in existing structures
Working in existing structures is shaped by uncertainty and tight spaces: existing documentation is often incomplete, component thicknesses vary, and reinforcement is located differently than expected. Conventional demolition methods with high impact pose risks to adjacent components and uses. There are also increased demands for cleanliness, vibration limitation, and operational safety in ongoing building operation.
Key influencing factors
- Structural analysis and load transfer: Identify load-bearing and bracing components; plan for temporary shoring.
- Accessibility: Transport routes, story heights, door widths, and load capacities determine the equipment concept.
- Emissions: Limits for noise, dust, and vibrations require adapted methods (e.g., splitting instead of chiseling).
- Material mix: Reinforced concrete, masonry, natural stone, steel, and composite constructions require differentiated methods.
- Operation and surroundings: Protection of people, equipment, installations, and sensitive areas takes priority.
Planning, investigation, and structural analysis
A robust investigation precedes any intervention. Components are measured, voids are located, the concrete compressive strength class is determined, and reinforcement is located. The result is an execution-ready work planning concept with coordinated safeguards.
Recommended procedure
- Survey of existing conditions: visual inspection, endoscopy, trial openings, rebar location, and material samples if required.
- Temporary safety: shoring, load redistribution, dust and splash-water protection, protective coverings.
- Method selection: splitting, shear-crushing, sawing, drilling, cutting—matched to component thickness, reinforcement, and surroundings.
- Work and exclusion zones: define, mark, secure access; define emergency and communication routes.
- Monitoring: vibration and crack monitoring, noise measurement, dust limitation—appropriate and documented.
Techniques and methods of selective deconstruction
Combined methods have proven effective for precise interventions in existing structures. Cutting or core drilling is often combined with hydraulic splitting and shear-crushing to create controlled separation joints and release components with minimal vibration.
- Hydraulic splitting with stone and concrete splitting devices or stone splitting cylinders: crack formation along defined borehole axes, low vibrations, high accuracy.
- Shear-crushing with concrete demolition shears or combination shears: targeted breaking and crushing of concrete, exposing reinforcement.
- Cutting techniques such as wall sawing and core drilling: dimensionally accurate separation cuts; in combination with shears/splitting cylinders, reduced effort during removal.
- Metal separation with steel shears for controlled cutting, Multi Cutters, or tank cutters: cutting of structural steel sections, pipelines, vessels, and tanks as part of building gutting.
Tools and equipment in existing structures: selection criteria
The selection depends on component geometry, material, accessibility, and boundary conditions. Hydraulic power packs provide the drive power; compact hydraulic power units are advantageous for upper floors and confined spaces.
- Performance parameters: splitting force, jaw opening, cutting force, stroke, hydraulic pressure, oil flow.
- Construction logistics: equipment weight, transport between floors, assembly and changeover times, power supply.
- Emissions: noise and dust generation, splash water; need for extraction and binding agents.
- Safety: low kickback, redundancies, easily accessible emergency stop functions, non-slip grip surfaces.
Concrete demolition shears and stone/concrete splitters in practice
Concrete demolition shears enable targeted breaking of concrete components and controlled exposure of reinforcement. Stone and concrete splitting devices generate high splitting forces through boreholes that open components along lines of weakness. Both methods are established in existing structures because they work with low vibration and precision.
Typical sequence
- Define separation joints and load transfer; install temporary shoring.
- Create core drillings or saw cuts to reduce stresses and define predetermined breaking lines.
- Insert splitting cylinders into boreholes; split step by step until controlled crack formation occurs.
- Rework with concrete demolition shears to straighten edges, expose reinforcement, and break components into manageable segments.
- Cut reinforcement with steel shears or Multi Cutters; sort the materials.
Advantages in existing structures
- Low vibrations and reduced crack risk in adjacent components.
- High dimensional accuracy for openings, recesses, and niches.
- Reduced noise emissions compared with percussive methods.
- Good controllability in confined spaces, overhead, and in sensitive areas.
Areas of application and interfaces
Concrete demolition and special demolition
In selective concrete demolition, components are released section by section and disposed of, often during ongoing building operation. Combinations of splitting, shear-crushing, and separation cuts minimize impacts on the existing structure.
Building gutting and cutting
Removal of non-load-bearing components, dismantling of installations, and cutting of steel beams are carried out with concrete demolition shears, Multi Cutters, and steel shears. Tank cutters are used for vessels and large hollow bodies, provided the conditions allow safe execution.
Rock excavation and tunnel construction
In underground or urban situations, low vibrations and minimal blasting-induced vibrations are decisive. Stone splitting cylinders enable controlled breaks in rock and high-strength concrete, for example during underpinning or pipe jacking.
Natural stone extraction
When releasing natural stone in existing structures—for example in historic masonry bonds or natural stone plinths—splitting allows clean separation faces with minimal damage to adjacent structures.
Special deployments
In special environments such as laboratories, hospitals, or ongoing production facilities, emissions control and process safety are the focus. Hydraulic splitting and shear methods are often the means of choice here.
Occupational safety, emissions, and permits
Safety takes precedence. Measures must be planned specifically for the project and continuously adjusted. Statements here are to be understood as general in nature.
- Dust: wet cutting, localized extraction, enclosures; regular cleaning.
- Noise: time windows, noise control, prefer low-noise methods (splitting, shear-crushing).
- Vibrations: monitoring, distance to sensitive areas, stepwise load reduction.
- Hazardous substances: substance knowledge, clearance measurements, trained personnel; proper disposal.
- Permits: coordination with authorities and owners; comply with requirements for site organization.
Site setup and logistics in existing buildings
Logistics determines pace and quality. Compact hydraulic power packs and modular tools facilitate work on upper floors, in shafts, and in confined areas.
- Transport routes: check load-bearing capacity of slabs, stairs, and elevators; set up intermediate storage.
- Material flow: source separation at the point of origin; short path from separation point to collection zone.
- Fall and edge management: secure openings; document lifting points and load take-ups.
- Supply: power, water, lighting, extraction; emergency equipment at hand.
Quality assurance and documentation
Evidence builds trust and minimizes consequential risks. Survey points, photos, and test reports document the controlled deconstruction and compliance with requirements.
- Expose and photograph reinforcement layers before cutting.
- Dimensional control of openings; check flatness and edge quality.
- Capture lists for material quantities; weighbridge tickets for disposal routes.
- Logs of vibration, noise, and dust values.
Sustainability and circular economy
Selective deconstruction is key to conserving resources. Splitting and shear-crushing often generate fewer fines than percussive methods and make type-specific separation easier. Recycled construction material can be used at higher quality if reinforcement is cleanly separated and concrete debris is as free from adhering material as possible.
Avoiding common mistakes
- Insufficient investigation: unexpected reinforcement layouts and embedded parts cause delays—plan trial openings and detection early.
- Missing temporary safeguards: prevent tilting or settlement by shoring and working in sections.
- Undefined separation joints: without predetermined breaking points, force demand and risks increase—place cuts and drillings in a targeted manner.
- Inadequate tool selection: too little jaw opening, insufficient splitting force, or the wrong jaw geometry increases effort and emissions.
- Poor disposal logistics: missing separation increases cost and reduces recycling rates.
Example: Creating an opening in a reinforced concrete floor slab
- Check existing conditions, locate reinforcement, install shoring.
- Core-drill or saw the contour; install dust and water protection.
- Use splitting cylinders along the contour to release the component.
- Use concrete demolition shears to break remaining ribs; cut reinforcement with steel shears.
- Recover segments, sort materials, rework edges, document dimensional accuracy.
Equipment categories of Darda GmbH at a glance (contextual reference)
Depending on the task and environment, the following groups of equipment are regularly used in existing structures: stone and concrete splitting devices and stone splitting cylinders for controlled splitting; concrete demolition shears and combination shears for shear-crushing and exposing reinforcement; steel shears and Multi Cutters for cutting metallic inserts; tank cutters for vessels and hollow bodies under suitable conditions. Hydraulic power packs provide the required energy supply and allow flexible combination of the tools.