The project cost target: how the federal government sets its building budget

The RBBau separates the Bauherr (the client) from the Bauverwaltung (the building administration). Under section A.3.2: "The client is responsible for the building task" (unofficial translation). Under A.3.5, building administrations are "the BBR and the authorities or bodies of the Länder entrusted within the framework of administrative assistance". The building administration carries out the project; responsibility for the task, and therefore for the budget, stays with the client.

This separation is the first idea that can be transferred. A private client who commissions project control, design and site supervision also keeps responsibility for the budget. Tasks can be delegated, but not the decision on the amount.

A separate procedure applies to larger projects. Under C.6, building tasks with construction costs in cost groups 200 to 600, gross, of EUR 10 million or more are carried out as building projects under section E, and within the remit of the Federal Ministry of Defence from EUR 20 million. These values are procedural thresholds, not cost limits: they determine which documents and decision steps are required.

The project cost target is more than an estimate. Section C.8 of the RBBau states: "The project cost target is the decisive control parameter for carrying out the building task." All later cost determinations, contract awards and decisions on changes are measured against it.

The term stands on its own. The RBBau speaks of the project cost target and does not use the concept of a cap as developed by case law for architects' contracts. Mixing terms from the two worlds attributes to the guidelines an effect they do not describe in that way. For private architects' contracts, the article on the construction cost cap deals with the contractual solution.

Under C.8, the project cost target consists of five components, a. to e., each "to be stated separately"; they cover four types of cost, because the risk costs appear in two groups, d. and e. Keeping the components separate is the real gain of the model, because any later deviation can be assigned to one component.

Price increases stand next to the construction costs, not inside them. This keeps the price level of the cost determination recognisable, and a later deviation can be distinguished according to whether it comes from the design or from the market. How a private client carries this separation over into their own total budget is shown in the article From the works budget to the client's total budget.

Risk costs are not a lump-sum reserve. The risk costs under d. are determined on a project-specific basis and listed individually; according to the wording, they cover risks with a very high probability of occurrence. In the budget procedure, only components a. to d. are included, the further risk costs under e. only where a project is budgeted individually and blocked under section 22 BHO. "All risks are documented in a risk register."

The client alone decides on the funds under d. C.8 provides: "The funds under d. are released by the client only when the risks occur." The building administration therefore cannot plan these funds in advance, for instance to offset an overrun on the construction costs, without a documented risk having occurred. For the blocked risk costs under e., the client applies to the BMF for release under section 36 BHO.

The register makes the reserve checkable. Each risk has an entry, an amount and a status. If it occurs, the amount is released and used; if it does not, the amount stays untouched. The same logic of a numbered register with a status also underpins the management of Nachträge (variations), described in the article Tracking variations in the budget: register and forecast.

The project cost target is set in two stages, linked to two stages of cost determination. For building projects under section E, it is set provisionally with the Initiale Projektunterlage (IPU, the initial project document), whose cost determination is carried out "at the level of the cost framework" (E 2.2). With the Finale Projektunterlage (FPU, the final project document), the final project cost target is set (E 3.2); its cost determination is carried out "at the level of the cost calculation" (E 3.1). For smaller projects, the RBBau provides the Einfache Bauunterlage (EBU, the simple building document), and alongside it the Haushaltsbegründende Unterlage (HBU, the budget justification document).

For the client, this means the budget is not fixed on an estimate but on the cost calculation. The provisional target steers the design; the final target is only set once the design has progressed far enough for quantities and qualities to be determined reliably. How the cost framework is drawn up is explained in the article on the cost framework and the cost estimate; what the cost calculation achieves as the third level, in the article on the cost calculation as the third level.

Setting the target in two stages separates steering from commitment. As long as there is only a cost framework, the provisional target gives the design a direction without tying the client to a figure that is still rough. Only the cost calculation, based on a developed design, carries the final target against which awards and changes are later measured.

Compliance is an aim, not an automatic outcome. E 3.3 states: "Compliance with the project cost target under section C.8 is to be sought." The RBBau thus assumes that deviations occur, and lays down who decides when they do.

Significant changes are reserved to the Lenkungsebene (the steering level). Under E 3.3: "Only the steering level decides on changes that significantly alter the framework of the project." If the approved framework cannot be kept to, a decision must be obtained from the body that approved the project or released the funds. The project is not interrupted in the meantime.

Early warning is mandatory. Section D.4 requires that, "where deviations from the agreed deadlines and cost targets are emerging", the client is informed without delay and proposals for alternatives are made. The building administration therefore reports not only the overrun that has occurred but the one that is emerging, and it brings solutions with it.

The applicable rules depend on when the building task began. Under G.3, the RBBau in its present form applies to building tasks begun after 1 October 2022; for earlier ones the old version applies, unless otherwise agreed. Anyone working as a party on a federal project therefore first checks which version governs their project.

The RBBau does not bind private clients. Five of its rules, however, work in any project:

1. Divide the budget into four types of cost. Carrying construction costs, ancillary costs, expected price increases and risk costs separately makes every later deviation explicable.
2. List and register risks individually. A list of named risks with amounts replaces the lump-sum allowance and can be updated at every project step.
3. Manage the risk funds yourself. They are not handed over as part of the design budget, but released by the client only when a documented risk occurs.
4. Set the budget in two stages. A provisional target for the early design, a final one based on the cost calculation, which the client checks or has checked before committing.
5. Allocate decision rights in advance. Who may approve which change, from what point must the management, the owner or the supervisory board decide, and what early warning does the project controller or architect owe? These questions can be answered in contracts and an internal approval rule before the first deviation occurs.

What cannot be transferred are the procedural thresholds and documents. IPU, FPU and the steering level are instruments of the federal administration. A private client adopts the logic, not the forms.