These were the 28th bdla Site Managers’ Talks, held on 16 and 17 January 2026 in Hagen

The 28th Site Managers’ Forum, held on 16–17 January at the new venue in Hagen and attended by over 550 participants, marked a successful start to the bdla’s 2026 programme of events.

28th bdla Site Managers’ Forum, Hagen Town Hall

Tom Kirsten provided a detailed update on the latest developments in regulatory work. The focus was on requirements regarding planting height and post-planting care, as well as a new checklist for inspecting plants on delivery, included as an appendix to the ATV Planting Works guidelines. He also presented new FLL publications on cost planning for outdoor facilities and biodiversity, and reported on amendments to the Technical Delivery Conditions for perennials. Furthermore, he pointed out that the VFBau will be dissolved by the end of this year and merged into a new construction standards association.

Tom Kirsten, bdla Spokesperson for Construction Technology and Standardisation

Dr Sebastian Schattenfroh (bdla Legal Adviser, Gaßner, Groth, Siederer & Coll.) used clear practical examples to highlight legal pitfalls and the framework conditions surrounding construction addenda and the review of addenda in service phases 7 and 8. He emphasised that the scope of service obligations in the review of addenda depends on the contract; particularly when the aforementioned service phases are awarded separately. What is to be performed during the review of supplementary agreements depends on the architect’s contract. It became clear that reviews of supplementary agreements are heavily influenced by legal considerations, and he explained the boundaries between technical collaboration and impermissible legal advice.

In his presentation, Prof. Dr Felix Möhring from the Ostwestfalen-Lippe University of Applied Sciences discussed in depth the issue of cooperation in contracts for work and services from a construction management perspective. He addressed key elements of cooperation and how to measure them, disruptions to the construction process, and approaches to conflict resolution involving multiple project stakeholders.

In his presentation, Dietmar Ulonska (until 2024, Betonverband Straße, Landschaft, Garten e. V.) examined the issue of contradictions and potential solutions between the various sets of regulations governing concrete paving. He began by providing an overview of the applicable standards and their scope of application. He then went into greater depth, discussing construction contract agreements under the German Civil Code (BGB) and definitional approaches for standard construction methods as applied to paving surfaces and pavements, as well as the widely recognised concept of ‘anchor-based rules of good practice’.

Following on from this, Prof. Astrid Zimmermann (Osnabrück University of Applied Sciences) highlighted the tension between design and normative requirements. As an example, she cited accessibility and the associated requirements for railings, guardrails and handrails. Her presentation also addressed the nature conservation aspect of specialist tree-related construction supervision in the context of sustainable planning.

Prof. Dr Mark von Wietersheim (forum vergabe e.V.) presented Integrated Project Management (IPA) in construction and public procurement law and demonstrated how planning and execution can be brought together through a multi-party contract. Using practical examples, he illustrated how early collaboration, phased target costs and joint risk management can lead to greater transparency, planning certainty and fewer conflicts.

Silke Sous (Aachen Institute for Building Damage Research) kicked off the second day of the event with her presentation on level thresholds and accessibility. She addressed, in particular, problem areas, conflict resolution and the current regulatory landscape. In doing so, she presented a wide variety of case studies and proposed solutions for connection details. Specifically, she addressed, amongst other things, roof terrace waterproofing with membranes and the installation of window frames or balcony door thresholds in accordance with the Passive House standard.

Markus Illgas (Ulenberg Illgas Landscape Architects) gave a presentation providing an overview of current requirements for automatic irrigation systems and how water sources, storage and distribution can be intelligently combined – from the use of rainwater and greywater to automatic irrigation systems.
The focus was on standard-compliant planning, resource conservation and functional irrigation concepts for green spaces and sports facilities.

Prof. Dr Meuser (Osnabrück University of Applied Sciences until 2023) concluded the theoretical section with a presentation on the Federal Soil Protection Ordinance and the Substitute Building Materials Ordinance. He demonstrated how the Substitute Building Materials Ordinance and the Federal Soil Protection Ordinance can be applied in a legally compliant manner – from recycled building materials to the creation of root-penetrable layers. The focus here was on installation methods, assessment criteria and the role of the groundwater level in planning and landscaping.

This was followed by site visits to Ostpark Bochum (Johanna Reisch, Henning Larsen), the Hafenquartier Südliche Speicherstraße in Dortmund (Sebastian Kröger/Heike Junk, City of Dortmund, and Hellmut Neidhardt, BÜRO N), to the Klimagarten in Schwerte (Lutz Zangenberg/Tobias Schlottbom, Förder Landscape Architects) and to the BOB Campus in Wuppertal Oberbarmen (Véronique Faucheur, atelier le balto and Guido Bauer, Bauer+Fecke Landscape Architects). Two seminars took place in parallel: one on the ZTV Wegebau 2022 led by Arno Tröger, and another on the practical application of the EBV and BBodSchV led by Prof. Dr Helmut Meuser.