The nine phases and their weighting
For the service profile covering buildings and interiors the percentages are as follows. Both columns total 100 per cent but distribute that total differently.
| Phase | Designation | Buildings | Interiors |
|---|---|---|---|
| 1 | Grundlagenermittlung (initial appraisal) | 2 % | 2 % |
| 2 | Vorplanung (concept design) | 7 % | 7 % |
| 3 | Entwurfsplanung (developed design) | 15 % | 15 % |
| 4 | Genehmigungsplanung (consent design) | 3 % | 2 % |
| 5 | Ausführungsplanung (detailed design) | 25 % | 30 % |
| 6 | Vorbereitung der Vergabe (preparing procurement) | 10 % | 7 % |
| 7 | Mitwirkung bei der Vergabe (assisting procurement) | 4 % | 3 % |
| 8 | Objektüberwachung (construction supervision) | 32 % | 32 % |
| 9 | Objektbetreuung (aftercare) | 2 % | 2 % |
The rates for buildings and interiors diverge on four phases, and most overviews do not show this. Applying the building figures to a pure interiors commission misallocates around a tenth of the fee.
The shift makes sense substantively: for interiors, detailed design weighs more heavily, while consent and procurement generate less effort. The gap on detailed design is five percentage points and is the largest of the four.
Where the weight lies
Three observations about the distribution matter for contract drafting. Together they explain why the shape of the commission weighs more economically than the level of the table value.
| Observation | Share | What follows |
|---|---|---|
| Construction supervision carries almost a third | 32 % | phase 8 is by far the heaviest; a contract without it nearly halves the fee |
| Design up to consent carries only just over a quarter | 27 % (phases 1 to 4, buildings) | the design work the client perceives as the architect's real contribution is the smaller part in fee terms |
| Consent design is weighted strikingly low | 3 % | its actual effort depends on the federal state, the procedure and the building class, and can considerably exceed that share |
The third observation explains why that phase is so often governed separately in contracts. The second explains why a commission ending at consent carries less economically than it appears to.
What a basic service is
The ordinance defines Grundleistungen, basic services, as those generally necessary for the proper performance of a commission. They are allocated to individual phases within the service profiles in the annexes; for buildings and interiors the catalogue sits in Annex 10.
To be distinguished are besondere Leistungen, additional services. They are not covered by the HOAI weighting system, their listing in the annexes is not exhaustive, and their fee is freely negotiable. The article on additional services covers the boundary.
The phase is the smallest weighted unit
This point is frequently misunderstood and has direct consequences for invoicing. It governs above all what may be charged where a commission is incomplete.
The HOAI weights work phases, not individual basic services. Within a phase there are no official percentages for the individual items of the catalogue.
Where not all basic services of a phase are commissioned, only a fee corresponding to the share of the services transferred may be charged. The assessment of that share is not normed, however, but must be agreed, and in text form. The same applies where substantial parts of basic services are not transferred.
In practice, firms rely on published assessment tables from the professional literature. These are usable, but they are not requirements of the ordinance, and their application should be named in the contract. The system is covered in the article on partial commissions.
The four deeper articles in this branch
| Phases | Share, buildings | Content | Article |
|---|---|---|---|
| 1 to 3 | 24 % | from clarifying the task to a consentable design, including the cost estimate and the cost calculation | work phases 1 to 3 |
| 4 and 5 | 28 % | consent design and detailed design, the move from concept to buildable information | work phases 4 and 5 |
| 6 and 7 | 14 % | procurement, from preparing bills of quantities to assisting with the award | work phases 6 and 7 |
| 8 and 9 | 34 % | construction supervision with documentation and aftercare following handover | work phases 8 and 9 |
Phases 1 to 3 are also those from which the fee is derived, since the cost calculation arises there. Phases 8 and 9 carry the largest share although they produce nothing further in design terms.
Other service profiles weight differently
These percentages apply to buildings and interiors. Other service profiles distribute the fee markedly differently.
For transport infrastructure, for instance, 20 per cent falls on concept design and 25 per cent on developed design, while construction supervision is weighted at 15 per cent. There the weight sits in design rather than in supervision.
Anyone working across several service profiles therefore cannot transfer the rates. The overview is covered in the article on the other service profiles.
What applies to multiple projects and existing buildings
Two provisions alter the weighting without touching the phases themselves. Both act on the percentages and presuppose either an agreement or factual conditions.
For several essentially identical objects, the percentages of work phases 1 to 6 must be reduced where the objects are designed and built in temporal or spatial connection under the same building conditions. The reduction is staged, and phases 7 to 9 are unaffected since supervision arises per object.
| Repetition | Reduction | Phases affected |
|---|---|---|
| first to fourth | 50 % | 1 to 6 |
| fifth to seventh | 60 % | 1 to 6 |
| from the eighth | 90 % | 1 to 6 |
| n/a | none | 7 to 9 |
| The article on repetition reduction covers the conditions. |
For repair and maintenance work, it may be agreed in text form that the percentage for construction supervision be increased by up to 50 per cent of the weighting of that phase. This reflects that supervision effort on such work is disproportionately high.
Both provisions act on the percentages, not on chargeable costs. They are therefore to be distinguished from the instruments for building in existing stock covered in the article on the conversion supplement.
What the phases do not do
Two limits are worth observing so that the phases are not over-read. They concern the reach of the ordinance and the force of its percentages.
| Limit | What follows |
|---|---|
| They are not a schedule of contractual obligations | the services listed are not required on every project, and the result owed may demand services not listed there; what is owed follows from the contract |
| They reflect effort only on average | the percentages rest on typified assumptions; on a demanding consent procedure or a long construction period, actual effort per phase deviates considerably without the weighting changing |
Both limits act in the same direction: they mean the ordinance yields less for contract drafting than its level of detail suggests. The contract has to close the gap.
Since binding price law fell away, that deviation can be reflected contractually by agreeing a different distribution. The conditions are covered in the branch on fee agreements.
Related articles
This article reflects the position of the rules and case law at the date of checking and serves professional orientation. It does not constitute legal advice and does not replace assessment of the individual case.