The German guideline for regular structural safety inspections of buildings using Damage Consequence Classes, Robustness Classes, and S-V-D defect rating.

The Damage Consequence Class (Schadensfolgeklasse, CC) categorizes buildings by the potential severity of a structural failure. CC 1 covers low-consequence structures such as agricultural buildings, storage sheds, and single-storey buildings with spans under six metres where a collapse would endanger few or no occupants. CC 2 encompasses medium-consequence structures -- the majority of buildings encountered in practice, including office buildings, industrial halls, residential blocks, and multi-storey structures with spans exceeding twelve metres. CC 3 applies to high-consequence buildings where failure could result in mass casualties or major societal impact: assembly halls, stadiums, concert venues, hospitals, schools, and high-rise residential towers. The CC directly determines the maximum allowable inspection interval and the minimum qualification level of the inspector.

The Robustness Class (Robustheitsklasse, RC) evaluates a structure's inherent ability to redistribute loads following local damage or loss of a single element. RC 1 describes structures with low robustness -- statically determinate systems with no redundancy and the potential for brittle failure, such as single-span precast concrete frames or timber portal frames. RC 2 covers structures with medium robustness that have some system reserves through statical indeterminacy, allowing partial load redistribution if one element fails. RC 3 denotes highly robust structures with significant redundancy and plastic reserves -- cast-in-place reinforced concrete frames with continuous beams and moment connections fall into this category. RC 4 is reserved for structures explicitly designed for accidental actions, impact scenarios, and progressive collapse prevention. The lower the robustness, the shorter the inspection interval must be, because a single undetected defect could trigger disproportionate failure.

In the digital form, the inspector selects both the Damage Consequence Class and the Robustness Class at the start of the inspection. These two parameters together define the inspection scope: a CC 3 / RC 1 building -- for example, a large assembly hall with a statically determinate long-span roof -- demands the most rigorous and most frequent detailed inspections, while a CC 1 / RC 4 structure requires only periodic walk-throughs. The Building Type field (Bauwerksart) helps classify the structure: residential, office, industrial, assembly, school, or other. For further guidance on the classification methodology, refer to the technical publications of the Verein Deutscher Ingenieure (VDI).

For further guidance on the classification methodology, refer to the Association of German Engineers (VDI), which publishes and maintains the guideline.

The Begehung (Walk-through) is the most basic inspection level, typically performed by the building owner or custodian at regular intervals. It does not require engineering expertise and focuses on visible changes: new cracks in walls, water stains on ceilings, tilting of structural elements, unusual sounds, or doors and windows that no longer close properly. The walk-through serves as an early warning system -- if anything unusual is noted, it triggers a higher-level inspection. VDI 6200 recommends annual walk-throughs for all building classes, though the responsible owner may choose more frequent checks for high-consequence structures.

The Inspektion (Visual Inspection) is performed by a qualified expert -- a structural engineer or a professional with equivalent qualifications. The inspector visually examines all accessible structural elements, identifies defects, and assesses whether the building's structural safety is maintained. This level does not typically require destructive testing or special access equipment, but the inspector must be able to reach and evaluate all primary load-bearing elements: foundations (where visible), walls, columns, beams, floor slabs, roof structures, and connections. Every defect found is documented with photographs and rated using the S-V-D system. For standard CC 2 / RC 2-3 buildings, visual inspections are typically required every five to ten years.

The Eingehende Überprüfung (Detailed Inspection) is the most thorough level, reserved for high-consequence structures, buildings with known problems, or situations where the visual inspection reveals concerns that require deeper investigation. It is performed by a Sachverständiger (special expert) and may include material testing, core sampling, cover meter surveys, crack monitoring instrumentation, and structural recalculation. In the digital form, the inspector selects the Prüfungsart (Inspection Level) as the first classification field, which sets the expected scope and mandatory documentation depth for the entire assessment. The fourth level -- Ad-hoc or Event-based inspection -- is triggered by extraordinary circumstances such as storms, earthquakes, floods, fires, explosions, or the discovery of severe structural deficiencies during renovation work. It requires immediate assessment regardless of the scheduled inspection cycle.

Similar tiered inspection systems are found in the DIN 1076 bridge inspection, which defines five inspection types from visual checks to special inspections.

Standsicherheit (S) -- Stability -- evaluates how the defect affects the building's structural load-bearing capacity. A crack in a main load-bearing wall receives a far higher S-rating than the same crack type in a non-structural partition, because it directly threatens the primary load path. Corrosion of steel connections in an industrial hall's roof truss or spalling that exposes reinforcement in a ceiling slab both score high on the S-axis because they reduce the effective cross-section of critical structural members. An S-rating of 4 means stability is critically impaired or lost -- the building or affected section cannot safely carry its design loads and immediate propping, evacuation, or partial closure is required. An S-rating of 0 means the defect has absolutely no impact on the structure's load-bearing capacity.

Verkehrssicherheit (V) -- User Safety -- evaluates whether the defect poses a risk to occupants, visitors, or passers-by. For buildings, this axis covers falling facade elements, loose cladding panels, unstable balcony railings, crumbling balcony soffits, and overhead hazards from spalling concrete in parking garages or stairwells. A loose balcony overhang that could fall onto a pedestrian path scores high on V even if the building's overall stability is unaffected. Dauerhaftigkeit (D) -- Durability -- captures the defect's impact on the building's long-term service life. Efflorescence on basement walls, moisture penetration through the roof structure, early-stage timber rot, and surface corrosion of exposed steel members may not threaten stability today but accelerate deterioration and shorten the remaining useful life. In practice, D is almost always greater than or equal to S: any defect that impairs stability necessarily impairs durability, but many durability issues have no immediate stability consequence.

In the form, each defect entry requires the inspector to select the Component Group (Bauteilgruppe) -- Foundation/Cellar, Walls/Columns, Floors/Ceilings, Roof Structure, Facade/Cladding, or Balconies/Overhangs -- followed by the Material (concrete, masonry, steel, timber, or other) and the Defect Type (crack, spalling, corrosion, deformation, moisture, rot/insect damage, or loose connection). The inspector then assigns independent S, V, and D ratings on a 0-to-4 scale, selects a Recommended Action (no action, monitor, routine maintenance, repair, further investigation, or immediate propping/closure), and sets the Priority (immediate, short-term, medium-term, or long-term). Mandatory photo evidence documents every finding. This structured approach ensures consistent evaluation across different inspectors and buildings.

The same S-V-D methodology is applied in the DIN 1076 retaining wall inspection. An alternative multi-dimensional rating approach is found in the NEN 2767 condition assessment, which uses severity, intensity, and extent as three dimensions of defect assessment.

VDI 6200 historically did not define its own grading mathematics. In practice, the building inspection community adopted the numeric rating scale from RI-EBW-PRÜF -- the same system used for bridges and civil engineering structures under DIN 1076. The Zustandsnote is not a simple arithmetic average of individual defect ratings. Instead, the evaluating engineer considers the maximum S, V, and D values found across all defects, the extent and distribution of damage patterns, and the interaction between multiple defects that may individually appear minor but collectively indicate systemic problems. A single S:4 finding on a primary load-bearing column -- even if spatially limited -- can push the entire building's grade to 3.5--4.0 because stability is critically impaired. Conversely, widespread D:2 findings across a roof membrane (many areas with moderate durability concern) may aggregate to a higher grade than an isolated D:2 finding, because the extent signals systemic waterproofing failure rather than a localized defect.

The Stability Confirmed field is the most critical binary assessment in the entire inspection. After evaluating all defects and assigning the Zustandsnote, the inspector must explicitly confirm whether structural safety (Standsicherheit) is maintained for the building as a whole. A building can receive a relatively poor grade of 2.5 for durability issues while still having confirmed stability. Conversely, a single critical finding on a primary structural member can result in stability not being confirmed even if most of the building is in good condition. When stability is not confirmed, the consequences are immediate and severe: the building or affected areas must be evacuated, propped, or closed until an engineering assessment and remedial measures restore structural safety. The inspector also sets the Next Inspection Due date, which is driven by the CC/RC classification and the severity of findings.

All condition grades and measures are documented in the standards directory-compliant Building Logbook.

The Bauwerksbuch is more than an inspection report -- it is a living document that accompanies the building from its initial construction through every modification, repair, and inspection cycle until eventual demolition. It contains the original structural calculations and design documentation, records of all construction modifications and retrofits, the complete inspection history with defect records and photographs, all condition grades assigned over time, and the recommended measures with their implementation status. VDI 6200 Blatt 1.1 (Draft 2024) introduces standardized templates for Bauwerksbuch documentation, aiming to harmonize the format across Germany. Prior to this, documentation formats varied significantly between federal states and individual engineering offices.

The General Checklist (Annex D) of VDI 6200 defines the high-level gatekeeper questions that must be answered before specific defect recording begins. These questions identify systemic risk factors that affect the entire building: Has the building's use changed since the last inspection? A conversion from office to archive significantly increases floor loads. Have structural modifications been made -- removed walls, new openings, added floors? Have additional loads been introduced -- heavy machinery, solar panels, green roofs, dense shelving? Have environmental conditions changed -- neighboring excavation, increased vibration from new road or rail, rising water table? Is the previous inspection report available for comparison? These binary checks serve as a filter: any "Yes" answer demands detailed investigation of the affected areas before the general defect survey proceeds.

In the digital form, the Bauwerksbuch requirements translate directly into structured data. The General Checklist section captures the Annex D gatekeeper questions as boolean fields (Change in Use, Structural Modifications, Added Loads, Environment Changes, Last Report Available). Each answer is timestamped and preserved across inspection cycles, building a longitudinal record. The defect registry creates traceable entries that can be compared between inspections -- the same crack documented in 2020 can be tracked through 2025 and 2030, with photographs showing progression or stability. The Summary/Conclusion field captures the inspector's expert narrative that contextualizes the numerical grade, and the mandatory digital signature establishes legal accountability. This transforms the Bauwerksbuch from a paper folder into a searchable, auditable digital asset.

For additional information on building inspection, refer also to TÜV SÜD, a leading inspection service provider offering VDI 6200-compliant building assessments.