The new information sheet ‘Tolerances in Special Foundations’, published in September 2024, provides a guideline for determining and observing basically unavoidable ‘geometric deviations’ from the target state. This creates a common understanding of the classification of geometric tolerances, the definition of meaningful tolerances in the tender documents, and the handling of tolerances that can only be controlled with disproportionate effort among the areas of responsibility of procurement, planning and construction.

Large and complex construction projects regularly present the challenge of reconciling the quality of workmanship and functionality of structures with the requirements for adherence to deadlines and budgets. The dimensional deviations of actual geometric sizes compared to the planning are crucial for the functionality of components and thus for the safety and economic efficiency of a construction project. In particular, they are of outstanding importance in special civil engineering, since components such as pile foundations, sheet pile walls and sealing soles are usually located at inaccessible depths after construction. Unfortunately, disagreements about the specification of nominal dimensions and possible deviations in practice often lead to discussions between the parties involved in a construction project.

The 42-page bulletin examines dimensional tolerances from a contractual and constructional point of view and assesses them in the context of the regulations. Since many planning challenges in special civil engineering have not yet been comprehensively regulated, the bulletin is intended as a practical tool to reduce or, at best, completely avoid the costs of errors.

The bulletin was created with the help of PORR

The bulletin was created by the Verein zur Förderung fairer Bedingungen am Bau e.V. (Association for the Promotion of Fair Conditions in Construction) in collaboration with the German Federal Department of Specialised Foundation Engineering in the German Construction Industry Association and with the help of PORR. ‘The development is an all-round successful joint project of the specialised foundation engineering industry. It summarises the most important facts about tolerances, regulations and measurement methods. The bulletin is therefore a guideline for cooperation between customers, planners and contractors in specialised civil engineering,’ says Christian Rinke, Managing Director of PORR Spezialtiefbau and Chairman of the Association for the Promotion of Fair Conditions in Construction.

The bulletin can be downloaded here.