Primary demolition refers to the controlled releasing, separating, and removing of load-bearing and fit-out components in the first phase of a deconstruction project. The focus is on load-bearing elements made of concrete, reinforced concrete, masonry, or natural stone, as well as massive steel components. In this phase, structures are opened, component connections are separated, and load paths are deliberately altered to enable safe, predictable, and low-emission deconstruction. Mechanical and hydraulic methods are used, such as crushing with concrete pulverizers, non-explosive splitting with rock and concrete hydraulic wedge splitters, or cutting with shears and specialized tools. Primary demolition forms the basis for secondary demolition, sorting, and recycling.
Definition: What is meant by primary demolition
Primary demolition is understood as the initial intervention and separation phase of deconstruction, in which components are first released from the composite, converted into manageable segments, and removed under structural control. The aim is the safe exposure of structures, the interruption of force flows, and the creation of transportability and further processability. In contrast to secondary demolition, which aims at further crushing, sorting, and processing, primary demolition comprises the initial separation of concrete, reinforcing steel, steel sections, sheet metal, or natural stone. Typical methods include the crushing of concrete with concrete pulverizers, hydraulic splitting of rock or concrete using hydraulic wedge splitters and rock wedge splitters, as well as cutting steel components with hydraulic shears. Hydraulic power packs provide the necessary system pressure and flow for powerful yet controlled working movements; suitable hydraulic power units for demolition ensure consistent performance.
Process and methods in primary demolition
Primary demolition follows a structured sequence of analysis, separation, removal, and securing. In preparation, components are surveyed, reinforcement is located, and separation cuts are defined. Subsequently, load-bearing and bracing connections are specifically cut or broken, for example with concrete pulverizers on walls, columns, and slabs, or with hydraulic wedge splitters in massive foundations and rock. Depending on structure geometry, material, and boundary conditions (access, noise, vibrations), jaw-crushing, splitting, and cutting methods are selected or combined. Removal is carried out in sections to control load redistribution; temporary shoring, catch systems, and defined drop zones secure the process.
Methods and tools at a glance
Concrete pulverizers
Concrete pulverizers crush concrete through high compressive forces, open cracks along aggregates, and cut reinforcing steels via integrated blades. They are suitable for slab demolition, wall openings, the deconstruction of columns, and selective removal in existing structures. In noise-sensitive areas, they are a quiet and low-vibration alternative to impact tools.
Rock and concrete hydraulic wedge splitters
Hydraulic wedge splitters for rock and concrete work without explosives. After predrilling holes, rock wedge splitters apply controlled radial splitting forces into the component or the rock. The method is ideal for massive foundations, rock removal in tunnel construction and civil engineering, as well as precise demolition in zones with strict vibration limits.
Combination shears and Multi Cutters
Combination shears combine cutting and crushing to efficiently separate mixed structures of concrete and steel. Multi Cutters offer versatile cutting tasks for sections, sheets, and auxiliary structures. Both tool groups support primary demolition when different materials occur directly adjacent to each other.
Steel shears
Steel shears cut beams, rebar bundles, pipes, and sections. They are used when steel cores are exposed or steel structures must be removed first, for example in industrial halls, bridges, or tanks.
Tank cutters
Tank cutters are designed for the safe cutting open of vessels, boilers, and pipelines. In combination with gas-free certification and fire protection measures, they enable controlled cuts in industrial plants.
Hydraulic power packs
Hydraulic power packs supply the tools with pressure and flow rate. Decisive are stable pressure levels, sufficient cooling capacity, and demand-based flow for dynamic load changes in demolition operations.
Application areas in primary demolition
- Concrete demolition and special demolition: (concrete demolition and deconstruction) Selective deconstruction of slabs, walls, columns, foundations, and bridge parts with concrete pulverizers; splitting of massive components to reduce vibrations.
- Building gutting and cutting: Separating non-load-bearing components, trimming openings, removing attachments; steel and pipe cutting with steel shears, Multi Cutters, and tank cutters.
- Rock excavation and tunnel construction: Non-explosive splitting technology for profile correction, niche creation, invert adjustments, and portal widening with rock wedge splitters.
- Natural stone extraction: Quarry-near, crack-controlled splitting of blocks to preserve structure and minimize waste.
- Special applications: Work in vibration-sensitive zones (hospitals, laboratories), under heritage protection requirements, or in explosion-hazard areas (ATEX zone) with adapted cutting and splitting technology.
Planning, structural analysis, and occupational safety
A robust demolition concept considers load-bearing capacity, load redistribution, construction stages, and boundary conditions such as adjacent buildings, utilities, and traffic areas. Measures for dust suppression, fire protection, fall protection, and load introduction into temporary shoring are integral components. Legal requirements and regulatory stipulations must be assessed on a project-specific basis; the following notes are general in nature and do not replace case-by-case review: Release components only in sections, define secured drop and protection areas, identify and isolate utilities, proactively minimize emissions (noise emission, dust exposure, vibrations).
Selection criteria for tools and methods
- Material and strength: Concrete strength, aggregate density, reinforcement ratio, prestressing steel, material thicknesses for steel.
- Component geometry: Component thickness, opening width, accessibility, overhead or shaft installation positions.
- Boundary conditions: Permissible vibrations, noise limits, dust management, available power supply.
- Performance parameters: Jaw force, splitting force, cutting diameter, jaw opening, cycle time, hydraulic pressure and flow rate.
- Process and disposal logistics: Segment sizes, crane and lifting capacities, sorting options for recycling, and waste disposal logistics.
Working under restrictions: noise, vibrations, dust
In sensitive environments, low-vibration and low-noise methods are required. Concrete pulverizers reduce impact peaks; hydraulic wedge splitters enable non-explosive work. Dust is bound by targeted watering, shrouds, and dust extraction. Cutting speeds and cycles are selected to minimize structural vibrations, supported by ground vibration monitoring as needed.
Process steps in detail
- Survey and concept: Clarify component buildup, reinforcement layout, utilities, residual stresses, access, and escape routes.
- Preparation: Site setup, protective scaffolds, coverings, shoring, utility isolation.
- Initial separation: Opening joints and nodes with concrete pulverizers or cutting steel constituents; drilling holes for rock wedge splitters.
- Controlled removal: Segmenting large components, lifting off or safely lowering; splitting massive areas to reduce forces.
- Interim logistics: Material kept by type, interim storage, routing of parts, keeping traffic areas clear.
- Securing and stabilization: Following up shoring, closing temporary openings, checking construction states.
- Transition to secondary demolition: Further crushing, sorting, and processing of materials.
Material separation and recycling
Efficient primary demolition prepares single-grade streams. Separation of concrete and steel aligned with demolition cuts reduces rework and increases the quality of recycling fractions. Targeted crushing with concrete pulverizers produces well-sortable piece sizes, while splitting technology guides crack paths in a controlled way and preserves aggregates.
- Early separation of concrete, reinforcement, metals, and fit-out material.
- Optimized segment sizes for transport and equipment in secondary demolition.
- Documentation of material flows for verification and recovery.
Special features in tunnel and rock environments
In tunnel construction and rock demolition, low vibrations, controlled crack propagation, and precise profile guidance are crucial. Rock wedge splitters enable the non-explosive opening of rock structures and the reworking of profiles. In combination with concrete pulverizers for concrete lining components, hybrid structures can be deconstructed safely and predictably.
Quality assurance and documentation
Quality in primary demolition means reproducible cuts, controlled component movements, and clean separation joints. Inspections include visual checks, dimensional accuracy, emission measurements, and tracking of structural assumptions. The documentation includes separation points, sequences, tools used, hydraulic parameters, and material quantities. It serves as a basis for optimizing subsequent work steps and for proof to clients and authorities.
Practical tips for safe implementation
- Keep load paths in view: Choose sequences so that no unintended redistributions or tipping occur.
- Plan to reduce tool changes: Combined work steps with concrete pulverizers and hydraulic shear minimize setup times.
- Optimize drill pattern for splitting technology: Adjust hole spacing and depths to component thickness and rock fabric.
- Keep hydraulics stable: Monitor hydraulic pressure and flow rate to ensure constant crushing and splitting forces.
- Manage emissions proactively: Integrate dust suppression systems, shielding, and ground vibration monitoring early.
Reference to products and application areas of Darda GmbH
In primary demolition, different product groups from Darda GmbH are used depending on the task: concrete pulverizers for crushing reinforced concrete, hydraulic wedge splitters with rock wedge splitters for non-explosive separations, combination shears and Multi Cutters for mixed constructions, steel shears for sections and reinforcement, as well as tank cutters for vessels and pipelines. In the application areas of concrete demolition and special demolition, building gutting and cutting, rock excavation and tunnel construction, natural stone extraction, and special applications, the coordinated combination of hydraulic power packs and tools enables a controlled, predictable, and low-emission initial intervention.