A slab stone is a planar, comparatively thin unit of dimension stone or concrete used for paths, plazas, facades, stair systems, and technical applications. Whether a natural stone slab of slate, sandstone, granite, or a concrete slab with defined tolerances: decisive factors are load-bearing capacity, dimensional accuracy, slip resistance, and durability. In planning, construction execution, maintenance, and during deconstruction, tasks from building construction and civil engineering, landscaping, natural stone processing, and demolition technology overlap. In these phases, the application areas of Darda GmbH—from natural stone extraction via gutting and cutting to concrete demolition and special demolition—play a central role, especially when low vibration levels, precision, and dust-reduced methods are required.
Definition: What is meant by slab stone
A slab stone is a plate-shaped construction or cladding unit made of natural stone or concrete with length and width predominantly greater than thickness. Typical thicknesses—depending on material, use, and laying method—range from roughly 20 to 80 mm for paving and surfacing slabs, up to several centimeters or decimeters for structural slabs (e.g., floor slabs, ceiling overlays). Natural stone slabs are quarried from the rock mass or sawn from raw blocks; concrete slabs come from industrial production. The term includes, among others, terrace slabs, sidewalk slabs, facade panels, and large-format dimension-stone slabs.
Use and fields of application for slab stones
Slab stones are used in outdoor areas, public spaces, industrial environments, and on building envelopes. In natural stone extraction, plate-like rock layers are opened up and cut; during the construction process, slabs are laid, jointed, and maintained; in deconstruction, surfacing and concrete elements are selectively separated, sorted, and recycled. For concrete slabs and reinforced components, concrete pulverizers can serve for low-vibration, controlled removal with concrete crushers. For natural stone slabs or massive rock slabs, hydraulic splitters and hydraulic wedge splitters offer a non-explosive option to induce precise cracks and separate in a targeted manner—such as in sensitive areas, tunnels, or inner-city locations.
Materials and properties
The materials determine suitability, surface appearance, load capacity, and appropriate laying and separation methods. Key parameters include compressive strength, flexural tensile strength, abrasion, water absorption, resistance to frost and de-icing salts, as well as slip resistance.
- Natural stone: slate (splittable, parallel to bedding), sandstone (easy to work, open-pored), granite/gneiss (high-strength, hard), limestone/travertine (warm-toned, porosity dependent), basalt (strong, dark). Splittability and anisotropic properties depend on the material.
- Concrete: standardized concrete slabs and large-format concrete dimension-stone units with defined tolerances and surfaces (ground, shot-peened, flamed/brushed). Reinforcement may be present in load-bearing slabs.
- Surfaces: rough, bush-hammered, flamed or textured for safe walkability; polished or ground for interior applications.
- Environmental aspects: water runoff, drainage capability, thermal behavior (heating), cleanability, and long-term color fastness.
Production and extraction
Extraction and manufacturing depend on the material, desired format, and permissible tolerances. Precision in thickness and flatness facilitates durable, functional installation.
Primary extraction in the quarry
Plate-like rocks are detached along natural bedding or joint planes. hydraulic rock and concrete splitters with hydraulic splitting cylinders produce controlled crack formation without explosives. In combination with hydraulic power units, splitting forces can be precisely dosed—advantageous for rock excavation and tunnel construction as well as natural stone extraction where low vibration levels, noise, and dust emissions are required. Sawing, drilling, splitting, and edge finishing follow for formats and final processing.
Industrial production of concrete slabs
Concrete slabs are produced in serial processes with molds and surface treatments. Dimensional accuracy and thickness tolerances are crucial for level pavements. Edges may be chamfered or rounded, and the surface is designed according to the required slip resistance. For large formats, reinforcement, aggregates, and curing influence flexural strength and durability.
Formats, tolerances, and normative guidance
Slab stones are offered as rectangular or free formats. Important parameters are nominal size, thickness, flatness, and edge quality. For planning and tendering, standards and technical rules are often used (e.g., product standards for natural stone slabs outdoors and execution rules for paving and slab coverings). Such rules provide guidance on tolerances, test values, and laying principles; however, they do not replace project-specific assessment and must always be interpreted in context.
Laying slab stones
The right laying method depends on loads, subgrade, slab format, and water management. The goal is a flat, stable, draining build-up with durable joints and sufficient slip resistance.
Sub-base and bedding
For exterior areas, a frost-resistant, load-bearing sub-base is essential. Typical are base layers of crushed stone with capillary-breaking properties and bedding made of clean chippings or drainage mortar. Large formats require a plane bedding, uniform bearing, and low thickness variation. Under heavy loads (e.g., driveways), more robust systems or monolithic concrete layers with decoupling are appropriate.
Joints and edges
Joint widths are matched to format and tolerance. Jointing sands or permeable joint mortars secure position and support water discharge. For large fields, provide expansion joints. Edges should be protected against edge breakage and chamfered if required.
Tools and auxiliaries
Wet saws, cut-off grinder, and splitting tools are used to adapt slabs. For dimensionally accurate breaks in natural stone, splitting along the bedding is suitable. For thicker elements and for adaptations in existing structures, hydraulic splitters can create a controlled separation joint without excessively affecting adjacent components.
Processing, cutting, and separation
Depending on material and environment, wet cutting methods, drilling, and splitting are used. In sensitive interiors—for example during building gutting and concrete cutting—dust- and noise-reduced methods have priority. For massive concrete slabs, removal can proceed in sections with concrete pulverizers; reinforcing steel is then cut with steel shears or universally applicable hydraulic shears. The power supply is provided by hydraulic power packs, delivering the required forces with good controllability. For natural stone or for concrete without dense reinforcement, hydraulic wedge splitters enable the introduction of directed cracks to preserve edge quality and minimize vibrations.
Demolition, deconstruction, and recycling
During deconstruction, slab stones are selectively lifted, separated, and sorted. In practice, the scope ranges from removing sidewalk and terrace slabs to demolishing reinforced floor slabs, platforms, and facade elements. concrete pulverizers enable controlled, low-vibration removal of concrete slabs during concrete demolition and special demolition as well as in building gutting. hydraulic splitters are practical where non-explosive rock removal is required or adjacent structures must be protected. Natural stone slabs can often be reused or reprocessed as dimension stone; concrete slabs can be processed into recycled aggregates. Material recycling depends on purity, material class, and regional regulations.
Safe workflows
Before working on slab constructions, load behavior, load transfer, and service routing must be clarified. shoring, load distribution, and defined lifting and securing points must be planned. Dust protection and noise control, securing the work area, and appropriate personal safety equipment are mandatory. Low-vibration methods—such as hydraulic splitting—can reduce risks to adjacent components. Notes on standards and occupational safety serve as general guidance and do not replace project-specific planning.
Typical damage and assessment
For slab pavements, damage such as edge breakage, spalling, cupping, cracks, voids, efflorescence, or discoloration can occur. Causes include insufficient bedding, incorrect material selection, lack of drainage, overloading, or thermal restraint. For concrete slabs, concrete carbonation and rebar oxidation also occur; for natural stone, freeze–thaw cycles and salt exposure are critical. Measures range from re-jointing and recompaction to partial replacement or orderly deconstruction. For removal of individual areas, selective methods such as concrete pulverizers or splitting along existing joints and bedding have proven effective.
Quality criteria and service life
The durability of a slab covering depends on the interaction of stone or concrete quality, structural detailing, sub-base, joints, drainage, and maintenance. Key quality criteria are material-appropriate surface finishing, sufficient thickness relative to format, low thickness variation, suitable joint widths, a slip-resistant surface, and a substructure appropriate to use. Regular cleaning, protection from standing moisture, and proper joint maintenance increase service life.
Practical examples from the application areas
In inner cities, large-format natural stone slabs are often laid on permeable systems; later replacement of individual slabs can be achieved with low vibrations by targeted splitting and careful lifting. In industrial plants, deteriorated concrete floor slabs require controlled deconstruction: concrete pulverizers remove the concrete step by step, steel shears or hydraulic shears cut the reinforcement, and hydraulic power packs provide the necessary energy. In rock excavation and tunnel construction, splitting cylinders help to release plate-like jointed rock areas in a controlled way. In natural stone extraction, hydraulic splitters improve yield along natural bedding when non-explosive rock removal is required.
Planning and tendering
For successful implementation, material, thickness, format, surface finish, slip resistance, laying method, joint pattern, and substructure should be defined at an early stage. Load assumptions, water management, and connection details must be considered integrally. Over the life cycle, it is worthwhile to consider disassembly and reuse options: demountable constructions, single-material layers, and accessible joints facilitate later deconstruction. In work on existing structures, planning for low-vibration methods—such as the use of concrete pulverizers or hydraulic splitters—can reduce risks and stabilize the construction process. All information serves technical classification and does not replace project-specific planning or verification.