German construction contract procedures (VOB) - Part C: General technical specifications in construction contracts (ATV) - Flooring works

Standard Overview and Technical Background

DIN 18365:2016-09, a key component of Part C of the German Building Contract Code (VOB), is the technical specification for floor covering projects. Published in September 2016, this standard replaces the August 2015 version, primarily incorporating editorial revisions and updated references. Dating back to 1925, the standard has undergone numerous revisions, reflecting the continuous improvement and technological advancement of the German building standards system.

Scope of application and exclusions

This standard applies to the installation of rolls and sheets of flooring, including linoleum, plastic, elastomer, textile, and cork flooring, as well as the installation of multi-layer composite flooring. However, it explicitly excludes the installation of natural stone, concrete products, ceramic tiles, screeds, poured asphalt, parquet, and wood tile floors, all of which have corresponding dedicated standards and specifications.

Material Technical Requirements System

This standard establishes a comprehensive material technical specification system, citing over 30 European and German standards to ensure the performance and quality consistency of flooring materials. Key material requirements include:

2.1 General Requirements

Based on DIN EN 14041 and DIN EN ISO 10874, this standard specifies the basic performance requirements and classification system for flooring materials, ensuring that the materials meet comprehensive requirements for mechanical properties, environmental adaptability, and safety.

2.2-2.7 Special Material Specifications

Specific technical specifications have been established for different types of flooring: Linoleum flooring must comply with the DIN EN 686-688 series; PVC flooring must meet more than 10 standards, including DIN EN 650-652; elastomer flooring must comply with DIN EN 1816-1817; and textile flooring must adhere to the classification requirements of DIN EN 1307.

2.8 Appearance Quality

The flooring color must only vary slightly from the sample to ensure visual consistency, which is crucial for the overall aesthetic appearance of large-scale installations.

2.9-2.11 Auxiliary Material System

The adhesive must comply with DIN EN 14259 to ensure a strong and lasting bond with the flooring, underlayment, and base layer; the underlayment material must comply with DIN EN 12455 and 12103; the primer and leveling materials must adhere well to the base layer and provide a suitable bonding base for the adhesive.

Key Technical Requirements for Construction Process

3.1 Key Points of Base Layer Preparation

Before construction, it must be confirmed that the base layer meets the paving requirements: the moisture content complies with DIN 18560; the surface strength and flatness meet the tolerance requirements of DIN 18202; and it is clean and free of contamination. For floor heating systems, moisture measurements may only be performed at marked measuring points to avoid damage to the heating device.

3.2 Dimensional Tolerance Control

Dimensional deviations must be within the limits specified in DIN 18202. Surface irregularities visible in sidelight must not exceed the limits specified in row 3 of Table 3 of DIN 18202:2013-04. Required flatness is a special service and must be agreed upon separately.

3.3 Substrate Preparation

The substrate must be cleaned by sanding and vacuuming. Screeds and dry floors that do not adhere well to the screed (e.g., calcium sulfate, magnesium sulfate, and cement screeds) must be primed. For floors installed without an underlay, the substrate must be leveled with a screed.

3.4 Floor Installation Details

Floors must be installed without an underlay. If an underlay is used, its joints must be staggered with the floor joints. For glued installations, the adhesive must be applied fully. The installation direction is determined by the contractor. Joints in the rolls are permitted only for rolls longer than 5 meters and must not be less than 1 meter in length. Patterned rolls must be installed in a matching pattern. Resilient floors are generally not welded or caulked.

3.5 Multi-layer composite floor installation

Floating multi-layer composite floors must be connected longitudinally and at the ends according to system requirements to ensure joint quality and overall stability.

Definition of additional services and special services

Special services include, but are not limited to: provision of temporary sheds and warehouses (if unavailable from the client), removal of old flooring and adhesive layers, handling of special contamination, achieving flatness exceeding DIN 18202 requirements, installation of special trim and transition strips, floor welding and caulking, etc.

Measurement Rules and Calculation of Quantities

5.1 Measurement Principles

Quantities are determined based on the paved area or fabricated length. Simplified measurement rules, such as the excess measurement rules and individual regulations, apply. Area measurement is based on the paved area dimensions, and length measurement is based on the maximum length of the component.

5.2 Measurement Method

The area of bounded components is measured to the bounding component (unplastered and unfinished); unbounded components are measured to their actual dimensions; steps and thresholds are measured to their maximum dimensions. Length is measured based on the maximum possible extended length of the component. Inlaid patterns and markings in the floor are measured separately.

5.3 Excess Measurement Rules

When measuring area, holes, inlaid patterns, and joints larger than 0.1 m² are not included in the project quantity; when measuring length, interruptions exceeding 1 meter are not included. These rules ensure fair and reasonable measurement.

Technical Implementation Recommendations and Precautions

Key Points for Substrate Preparation

Before construction, the substrate must be thoroughly checked: moisture content measurement, flatness testing, and surface strength testing. In particular, floor heating systems must be operated strictly in accordance with the heating protocol to avoid damage to the heating system.

Material Compatibility

Select the appropriate flooring material based on the intended use environment: moisture-resistant PVC (DIN EN 13553) for humid areas; wear-resistant materials for high-traffic areas; and conductive flooring for areas requiring anti-static treatment.

Construction Environment Control

Maintain a suitable construction temperature (minimum 15°C) and humidity to ensure proper adhesive curing and dimensional stability of the flooring. Provide written cleaning and maintenance instructions after construction to ensure proper maintenance.

Joint Treatment Techniques

Metal sheet seams should be cut neatly and joined flush. Patterned flooring must be installed with the pattern aligned. Resilient flooring generally does not require welding or caulking unless otherwise specified. The installation of electrically conductive flooring must comply with VDE regulations.

Edge Finishing and Transition Treatment

Skirting and trim strips should be installed according to the material's characteristics, with beveled corners. Resilient stair trim strips should only be installed on the tread surface. Appropriate transition strips should be used to ensure smooth and safe transitions between different materials.

Standard Application Practice Cases

Medical Facility Flooring Project

A hospital project employed antibacterial PVC flooring, selecting flooring materials suitable for wet areas in accordance with DIN EN 13553. During construction, special attention was paid to seam welding to ensure seamless and easy cleaning. Conductive materials were selected to meet the anti-static requirements of medical equipment. During installation, the finished area was strictly protected to prevent cross-contamination.

Commercial Space Laminate Flooring Installation

A shopping mall employed floating laminate flooring, selecting high-wear-resistant materials in accordance with DIN EN 13329. During construction, the flatness of the base layer was strictly controlled (using self-leveling screed) to ensure the stability of the floating paving system. When paving large areas, expansion joints were carefully reserved to prevent deformation caused by temperature fluctuations.

Historic Building Restoration Project

In the restoration of a historic building, traditional linoleum flooring (DIN EN 688) was used to preserve the original appearance of the building. During construction, special attention should be paid to controlling the moisture content of the base layer to prevent the newly laid floor from becoming damp and deforming; traditional installation techniques should be selected to ensure consistency with the historical style of the building.

Standard Development Trends and Outlook

As an important component of the German building standards system, DIN 18365 continues to follow the development of material technology and advances in construction techniques. Major development trends in recent years include: increasing requirements for environmentally friendly materials, emphasizing low V emissions and recyclability; more detailed technical requirements for flooring compatible with underfloor heating; further strengthening of anti-slip safety performance requirements; and the gradual promotion of the application of digital construction and BIM technology in standard implementation.

Possible areas of focus for future revisions include: the inclusion of new sustainable flooring materials, energy-saving improvements to installation techniques, further coordination with the EU standard system, and application guidelines for digital measurement and acceptance technologies. These developments will drive flooring projects towards higher quality, greater environmental friendliness, and greater efficiency.