Plaster removal is a fundamental work step in refurbishment works, deconstruction and structural repair. It means the targeted removal of plaster layers—such as gypsum, lime or cement plaster—from concrete and masonry surfaces to expose substrates, inspect them, or prepare them for subsequent operations. In many projects, plaster removal is the prerequisite for controlled work on load-bearing components, for assessing reinforcement, or for safely gripping components with concrete demolition shear and hydraulic rock and concrete splitters.
Definition: What is meant by plaster removal
Plaster removal refers to the mechanical removal of plaster and filler layers down to the sound mineral substrate. The aim is a substance-preserving exposure without relevant damage to the masonry or concrete. Plaster removal can be local (e.g. at damaged areas) or across larger areas (e.g. during refurbishment works, retrofits, deconstruction). It prepares for subsequent tasks such as substrate repair, joint openings, separation cuts, anchor drilling or gripping demolition with concrete demolition shear. For more substantial interventions in concrete members, plaster removal is often the first step before rock wedge splitter and concrete splitter initiate separation or loosening processes inside the component.
Importance in deconstruction and refurbishment
In concrete demolition, special demolition as well as during building gutting and concrete cutting, plaster removal provides clear visibility of component edges, joints and reinforcement layers. This improves the assessment of the substance and enables precise bite points for concrete demolition shears, without plaster residues impairing the gripping process or creating a risk of slippage. For massive components, the completed plaster removal can mark the location of drill points through which hydraulic wedge splitters in combination with compact hydraulic power units are used. In tunnel construction and rock excavation, plaster removal occurs as the removal of shotcrete layers (e.g. for inspection or to prepare further measures). In natural stone extraction, the focus is rather on exposing bedding joints, veneers or mortar overlays so that subsequent splitting or cutting processes can be planned.
Typical methods and tools
The choice of method depends on the plaster type, layer thickness, substrate strength and the requirements for limiting dust, noise and vibration. Basically, a distinction is made between handheld, semi-mechanical and mechanical/abrasive methods.
Manual and semi-mechanical methods
- Removal with hammer and chisel for controlled, small areas
- Light breaker hammers or rotary hammers with chisel bit for larger areas
- Spatulas, scrapers and pull scrapers for edge and detail work
Mechanical and abrasive methods
- Plaster milling machines and grinders for uniform removal, optionally with dust extraction
- Blasting methods (gentle blasting, dry ice, granulate) for sensitive substrates
- High-pressure water jetting for gentle detachment of low-binder layers
In the deconstruction environment, mechanical methods predominate; they provide good area productivity and expose the substrate sufficiently so that subsequent devices such as concrete demolition shear find defined edges and gripping zones. For highly heterogeneous layers or in monument conservation, gentler methods are preferable. Where rock wedge splitter and concrete splitter will be used later, the plaster removal must be carried out so that drill points and re-entrant corners are accessible.
Process chain from plaster removal to structural intervention
- Preliminary investigation: Identification of plaster system, layer thicknesses, pull-off adhesion, potential hazardous substance content as well as reinforcement layers and routing of utility lines.
- Selection of the removal method: Weighing area productivity, component protection, emissions, and logistical boundary conditions (access, power/hydraulics, extraction).
- Plaster removal: Area-wide or local removal down to the sound substrate; edges and joints are exposed.
- Cleaning: Removing dust and residual adhesion; visual inspection for cracks, honeycombing, corrosion, chloride contamination or moisture indication.
- Marking and preparation: Marking cut lines, drill points or grip points for concrete demolition shears; drilling for hydraulic wedge splitters if required.
- Structural intervention: Gripping or cutting demolition, splitting, shearing operations; supplied as needed via hydraulic power packs.
- Follow-up work: Smoothing, edge finishing, protective coatings or repair as specified.
Clear separation of these steps increases occupational safety, improves the quality of cut surfaces and reduces undesirable side effects such as spalling when using concrete demolition shears.
Correctly assessing substrates, plaster types and layer build-up
The type of plaster determines the resistance to removal, tool wear and the risk of substrate damage. Equally decisive are the load-bearing capacity and moisture distribution of the substrate.
- Gypsum plaster: easy to shape, often high dust content during removal; note moisture sensitivity.
- Lime plaster: usually separates well; for historic plasters, take care due to aggregates and possible voids.
- Cement plaster: higher strength, abrasion- and impact-resistant; mechanical removal with higher force demand.
- Renovation plasters: porous, intended for damp and salt-laden substrates; prefer gentle methods.
- Filler and leveling layers: thin-layered, often grindable or blastable; consider bond bridges on concrete.
Special aspects for ETICS and shotcrete
For external thermal insulation composite systems, distinguish between plaster layer, mesh-reinforced filler and insulation. Removal proceeds layer by layer to preserve the substrate. Shotcrete layers in tunnel or adit areas are detached mechanically or with high-pressure water depending on strength; pay attention to loose rock, anchor heads and built-in components.
Quality assurance: Surface requirements and testing
After plaster removal, the surface is clean, sound and free of residual plaster that could impede further work. In practice, the following criteria have proven effective:
- Exposed edges, joints and gripping areas without loose coating
- Substrate not torn or excessively roughened (component protection)
- Visual inspection for corrosion, cracks, honeycombing, efflorescence
- Indicative pull-off or surface strength tests if required
- Low-dust cleaned surface for marking, drilling and gripping
For critical components, requirements should be defined on a project-specific basis. Technical codes can provide orientation, but must always be transferred to the specific application.
Occupational safety, emissions and environment
Plaster removal generates dust, noise and vibration. Protective measures must be matched to the method and apply in particular indoors and during ongoing operations.
- Dust: extraction at the source, negative pressure containment, personal protective equipment, prefer low-dust methods
- Noise: selection of suitable equipment, acoustic damping, scheduling, hearing protection
- Vibrations: coordinated equipment use, buffer zones at sensitive components
- Water: controlled use, avoidance of washouts, proper collection of slurries
Legal requirements and occupational health limits must be observed. Statements to this effect are fundamentally non-binding and must be specified for the project.
Avoiding component damage and typical failure patterns
- Spalling at edges due to too steep a chisel angle or too high an impact
- Grooves and breakouts in concrete due to unsuitable milling tools
- Unintentional chiseling of joint sealant or masonry joints
- Hidden utilities damaged due to excessive penetration depth
- Carryover of chloride- or sulfate-bearing material into adjacent areas
Practical notes
- Remove from edges towards the surface, not the other way around
- Sonde for voids and treat them separately
- Treat load-transferring areas particularly gently
- Before using concrete demolition shears, free gripping areas completely from residual plaster
- For planned use of rock wedge splitter and concrete splitter, mark drill points early and keep them clear
Disposal, recycling and material flows
Removed plaster must be collected separately depending on composition and adhesions. Gypsum- and cement-bearing fractions, contaminated mixtures and potentially hazardous materials must be treated differently. Regional requirements for disposal, recycling and documentation are decisive. An early sorting strategy facilitates verification and lowers costs. During the project, avoid mixing plaster residues with concrete debris when concrete demolition shears are intended to separate large concrete pieces later—clean material flows improve recoverability.
Special application fields and interfaces
In concrete demolition and special demolition, plaster removal paves the way for precise gripping and cutting operations. Exposed edges allow safe positioning of concrete demolition shears and facilitate the defined separation of component segments.
In building gutting and concrete cutting, removal enables the discovery of embedded parts and installation channels. Markings for separation cuts can be set more accurately; during subsequent use of multi-cutters, combination shears or steel shear, access to reinforcement or inserts is clearer.
In rock excavation and tunnel construction, shotcrete is partially removed to prepare inspections, measurements or renewed stabilization works. Afterwards—depending on construction state—hydraulic wedge splitters can be used where separations are required in massive zones.
In natural stone extraction, the classic plaster is less the focus, but mortar overlays, veneers or pointing often have to be removed to expose bedding surfaces for splitting operations.
For special deployments—for example in sensitive areas or heritage conservation—gentle methods take priority. Here, plaster removal must be adapted to the material before further processing steps follow.
Performance indicators and costing approaches
Area productivity depends on layer thickness, strength, method and accessibility. Thin, brittle layers are much faster to remove than high-strength, thick cement plasters. As a rule of thumb, variable ranges from a few to several dozen square meters per shift and day apply for handheld methods; mechanical methods can exceed this. Trial areas are helpful for planning. Additional time requirements arise from dust protection, logistics, extraction and the required surface quality for subsequent work with concrete demolition shears or rock wedge splitter and concrete splitter.
Documentation and evidence
Complete documentation facilitates acceptance and planning of subsequent work. Sensible elements include:
- Photo documentation before, during and after plaster removal
- Details of methods, equipment and parameters
- Recorded findings (cracks, corrosion, voids, reinforcement layers)
- Logs of emission control measures
- Evidence of material flow separation and disposal
These documents form the basis for subsequently positioning concrete demolition shears in a targeted way or planning boreholes for rock wedge splitter and concrete splitter. Darda GmbH is frequently active in projects at the interface after plaster removal, when components have to be separated, split or gripped in a controlled manner.