Anyone who plans, renovates, or manages a building cannot avoid Service Phase 2 of the HOAI. This is the phase in which a construction project is transformed into an initial concrete concept: Here, landscape architects, architects, and engineers develop the fundamental approaches, weigh different options, and set the direction for the entire project. The decisions made during preliminary planning shape all subsequent phases through to construction.
- What Service Phase 2 of the HOAI entails and how it differs from adjacent phases
- Which services are part of preliminary planning and what is considered a special service
- What role Service Phase 2 plays in landscape architecture and open space planning
- How the fee for preliminary planning is calculated and what valuation criteria apply
- What typical errors and misunderstandings occur in practice
- How preliminary planning is coordinated with other specialist planners and authorities
- What documents and deliverables must be available at the end of Service Phase 2
- How Service Phase 2 fits into the broader context of planning law and project management
What Is Service Phase 2 of the HOAI? Definition and Classification
The Fee Schedule for Architects and Engineers (HOAI) divides planning services for buildings, outdoor facilities, civil engineering structures, and other types of projects into nine service phases. Service Phase 2 is designated “Preliminary Planning” and marks the transition from the conceptual preliminary study to the first detailed planning proposal. While Service Phase 1—the preliminary study—is still focused on clarifying the project scope and compiling all relevant information, Service Phase 2 of the HOAI involves developing concrete solution approaches based on this foundation, comparing them, and consolidating them into a preliminary planning concept.
The HOAI is a German government regulation on pricing that sets binding fee frameworks for the services it governs. It applies to architects, landscape architects, interior designers, and various engineering disciplines. The current version of the HOAI dates from 2021 and implements a ruling by the European Court of Justice, which had deemed the previously applicable mandatory minimum and maximum rates to be contrary to European law. Since then, the HOAI fee schedules have served as guidelines that form the basis for fee agreements without being legally binding. Nevertheless, the structure of the service phases and the descriptions of the basic services in the HOAI remain decisive for professional practice.
Service Phase 2 of the HOAI is of particular strategic importance for all parties involved in the planning process, as this is where the essential course is set. Decisions regarding site development, materials, program allocation, open space layout, or technical systems—made during the preliminary planning phase—can only be revised in later phases at considerable expense. In this context, experts refer to the “freezing” of planning decisions: the further a project progresses, the more expensive and time-consuming any fundamental change becomes.
Basic Services in Preliminary Planning: What the HOAI Specifically Requires
The HOAI describes so-called basic services for each service phase—that is, the scope of services typically required to achieve the planning objective, the fees for which are outlined in the fee schedules. For Service Phase 2, these basic services for outdoor facilities—which constitute the core scope of work for landscape architects—include, among other things, the analysis of the basic conditions, the development of a planning concept with a schematic representation, the clarification of key interrelationships, surveys and measurements of the planning site, and a cost estimate in accordance with DIN 276.
The cost estimate in accordance with DIN 276 is a key deliverable of Service Phase 2. It provides an initial reliable estimate of the project’s anticipated total costs based on the preliminary planning documents. DIN 276 categorizes construction costs into cost groups; for outdoor facilities, cost groups 500 (outdoor facilities) and 700 (incidental construction costs) are particularly relevant. The cost estimate in the preliminary planning phase still has a relatively wide range because many details have not yet been finalized. Nevertheless, it is sufficiently binding to provide the client with a basis for deciding whether the project is economically feasible in its planned form.
Preliminary planning also involves exploring alternative solutions. This is not a mere formality but a core task: The planner should demonstrate to the client that they have considered the task from multiple angles and that the chosen solution is not merely the only conceivable one, but the best one based on professional judgment. In landscape architecture, this can involve comparing different types of open spaces—such as a natural meadow-like setting versus a more formally designed landscape—or different access concepts for a city square. This analysis of alternatives demonstrates the planner’s diligence and protects both parties in the event of future disputes regarding the quality of the design.
In addition, during the preliminary planning phase, the results must be coordinated with the client and their approval obtained. This coordination step is more than a mere formality: It marks the transition from concept development to detailed planning and lays the foundation for commissioning Service Phase 3, the design planning phase. Without documented approval of the preliminary planning by the client, the contractual basis for further work is lacking.
Service Phase 2 in Landscape Architecture and Open Space Planning
For landscape architects, Service Phase 2 of the HOAI holds particular significance in terms of content, because outdoor spaces are most strongly shaped by fundamental conceptual decisions during this phase. Whether a city square is developed as a green public space or as a hard, multifunctional urban plaza; whether a schoolyard distributes recreational activities across the entire area or divides them into zones; whether a residential neighborhood is accessed via linear pathways or an organic network of paths: All these decisions are made during the preliminary planning phase and determine the character, usability, and maintenance requirements of a space for decades to come.
In open-space planning, it is also important to note that Service Phase 2 is often closely linked to planning-law procedures. Zoning plan procedures, urban development framework plans, or competition results often provide the starting point for the preliminary planning of open spaces. During Service Phase 2, the landscape architect must determine which requirements from these overarching plans are binding and what leeway they allow for the design of the open space. This requires a solid understanding of building planning law, particularly the Building Code and the Land Use Ordinance, as well as the relevant regulations governing open space planning.
Fundamental decisions regarding vegetation and ecology are also prepared during the preliminary planning phase. Whether a row of trees is planned with large-crowned urban trees or small-crowned ornamental shrubs, whether perennial plantings are designed as low-maintenance community plantings or as more elaborate display plantings, and whether rainwater is allowed to infiltrate, stored, or diverted: These questions affect not only the design but also the functionality, climate impact, and long-term costs of an outdoor facility. A thorough Service Phase 2 sets the course here without yet delving into the detailed aspects of the design planning.
Fees and Valuation: How Service Phase 2 Is Compensated
The fee for Service Phase 2 under the HOAI is calculated as the proportion of the total fee attributable to preliminary planning, multiplied by the fee derived from the billable costs and the fee zone. For the scope of services related to outdoor facilities, the HOAI assigns a percentage of the total fee to Service Phase 2. This percentage varies depending on the scope of services; for outdoor facilities, it generally amounts to seven percent of the total fee for basic services according to the current HOAI 2021.
The billable costs form the basis for the fee calculation and essentially correspond to the construction costs of the planning project—that is, the construction costs of the outdoor facilities in accordance with DIN 276. The fee zone indicates how demanding a planning task is: It ranges from Zone I (low requirements) to Zone V (very high requirements) and significantly influences the fee. For outdoor facilities in urban contexts with high design, ecological, and usage-related requirements, classification into fee zones III or IV is often appropriate. Classification into the correct fee zone is a professional decision that must be well-founded and agreed upon with the client.
Special services—that is, services that go beyond the basic services defined by the HOAI—are agreed upon and compensated separately. For Service Phase 2, these may include, for example, extensive variant analyses beyond the usual scope, the preparation of feasibility studies, participatory processes involving users or residents, or the development of maintenance concepts as standalone services. Experts recommend clearly identifying and agreeing upon special services at the time the contract is concluded to avoid subsequent fee disputes.
Coordination, Alignment, and Common Mistakes in Practice
Service Phase 2 of the HOAI is not an isolated planning service, but rather a coordinated process that brings together the contributions of various specialist planners. In complex projects, landscape architects collaborate during the preliminary planning phase with architects, structural engineers, building services engineers, traffic planners, soil consultants, and other specialists. Coordinating these contributions is a distinct service that, under the HOAI, is assigned to the project planner. For outdoor spaces, this means that the landscape architect must clarify the interfaces with civil engineering, drainage, lighting, and outdoor furniture at an early stage.
A common mistake in practice is to move on from Service Phase 2 too early—that is, to proceed to the design planning phase before the preliminary planning has actually been completed and approved. This often happens due to time pressure or because clients want to see quick results. The result is that fundamental conceptual issues that should have been clarified during the preliminary planning phase are carried over into the design planning phase, where they lead to considerable additional work. Design changes in Service Phases 3 or 4 that stem from unresolved preliminary planning issues must, according to the HOAI, generally be compensated as change orders, which can lead to additional fee claims and conflicts.
Another common misunderstanding concerns the level of detail required in the preliminary planning phase. Service Phase 2 of the HOAI does not require construction details, planting plans, or bills of quantities. It requires a conceptually sound, to-scale planning concept that documents the key decisions and enables a reliable cost estimate. Anyone who delves into the level of detail required for construction planning as early as the preliminary planning phase is wasting resources and risks having this detailed work rendered obsolete by later planning changes.
Coordination with government agencies also plays an important role in Service Phase 2. For many open-space projects, early discussions with the local nature conservation authority, the city planning office, the historic preservation authority, or the civil engineering office are necessary to clarify which requirements and restrictions apply to the project. Although these consultations are not explicitly listed as a basic service of Service Phase 2, they are part of professional practice and can be agreed upon as a special service if they involve a significant amount of work.
Results and Documentation at the End of Preliminary Planning
At the end of Service Phase 2 of the HOAI, a clearly structured preliminary planning package should be available, providing the client with a sound basis for decision-making. Typical deliverables include a detailed preliminary design plan drawn to an appropriate scale—often 1:500 or 1:200 in open-space planning—an explanatory design description, which outlines the concept, proposed solutions, and justifications for key decisions, as well as a cost estimate in accordance with DIN 276, broken down by cost categories.
The planning description is more than just an accompanying text: it serves as the argumentative backbone of the preliminary planning and documents why certain solutions were chosen and others rejected. A well-written planning description protects the planner in the event of future disputes because it demonstrates that decisions are based on a well-considered professional foundation. For landscape architects, it also offers the opportunity to convey the ecological, climatic, and social qualities of a design—qualities that cannot be fully conveyed through drawings alone.
The client’s approval of the preliminary planning should be documented in writing. This can take the form of meeting minutes, an email confirmation, or a formal approval statement. This documentation is a prerequisite for commissioning the next phase of services and protects both parties from misunderstandings regarding what was agreed upon. In practice, this step is often neglected, which can later lead to disputes over whether certain planning changes should be considered a redesign or a further development of the approved concept.
Service Phase 2 in the Context of the Entire Planning Process
Service Phase 2 of the HOAI is not an isolated planning stage, but rather an integral part of a continuous process that extends from the initial idea to the completed facility. Its significance becomes fully apparent only in the context of the other service phases: It builds on the preliminary study conducted in Service Phase 1 and lays the foundation for the design planning in Service Phase 3. Issues not clarified during the preliminary planning stage resurface as problems in later phases, often in a form that is more expensive and time-consuming to resolve.
For clients—especially public building owners and project developers—Service Phase 2 is the moment when they first gain a reliable idea of what their project will cost and what it will look like. The cost estimate from the preliminary planning phase is often the first figure presented to governing bodies, committees, or investor groups. It therefore has a political and economic dimension that goes beyond purely technical planning work. Planners who are aware of this dimension prepare their preliminary planning documents with this communicative aspect in mind.
The growing importance of climate adaptation, biodiversity, and blue-green infrastructure in urban development has significantly expanded the substantive requirements for Service Phase 2 in open space planning in recent years. Concepts for “sponge city” principles—that is, decentralized stormwater management in open spaces, heat mitigation measures through greening and shading, and habitat connectivity for urban biodiversity: All of this must be conceptually anchored as early as the preliminary planning phase if it is to be effective during implementation. Service Phase 2 of the HOAI is thus not only an instrument of planning law but also a central tool for quality assurance in the open spaces of growing and changing cities.
Those who take preliminary planning seriously save time, money, and stress in all subsequent phases. Those who treat it as a mere formality will pay the price later. This is no exaggeration, but rather the sober experience of every seasoned planner who knows how much work goes into a poorly prepared design phase and how rarely this work is adequately compensated.
