Work phase 1: initial appraisal
Weighting: 2 per cent, the lowest share in the whole service profile.
This phase serves to clarify the task and advise the client on the scope of services required. It includes formulating decision aids for selecting further specialist consultants and summarising the results.
Its share is the lowest in the whole service profile, and its actual effort frequently bears no relation to it. The duties to advise and inform are foremost here, and this is where the decisions with the greatest cost impact are taken.
A point of classification: the site inspection was brought into the basic services of this phase with the 2013 version. It is therefore covered by the fee, which older contract templates sometimes still show differently.
| Service | Classification |
|---|---|
| Site inspection | a basic service of phase 1 since 2013, covered by the fee |
| Briefing | an additional service, to be agreed separately |
| Cost framework | arises during briefing, outside the basic services |
The cost framework serves the client as the basis for deciding on the project itself rather than on the design. It therefore arises before the commission rather than within it.
Work phase 2: concept design
Weighting: 7 per cent, the same for buildings and interiors.
Concept design divides into six blocks of work. The third is the one whose scope is most often exceeded in practice.
| Block | Content |
|---|---|
| Basis | analysing the basis |
| Objectives | agreeing the objectives |
| Concept | developing a design concept including alternative approaches |
| Constraints | clarifying the constraints and requirements |
| Authorities | preliminary discussions on consentability |
| Result | summarising the results |
The basic services of this phase include the cost estimate under DIN 276 and comparison against the financial framework. Both are owed without separate agreement.
Since the December 2018 reissue of DIN 276, the cost estimate must be prepared at the second level of the cost structure rather than the first. Numerous templates and software defaults still carry the earlier requirement. The system is covered in the article on cost framework and cost estimate.
A point of classification: preparing a programme showing the principal construction activities has been a basic service of this phase since the 2013 version. A programme in greater detail remains an additional service.
Work phase 3: developed design
Weighting: 15 per cent, the highest share of the three design phases.
Developed design divides into five blocks of work. They end with a design that is both consentable and costed.
| Block | Content |
|---|---|
| Design | working up the design from the concept |
| Presentation | drawn presentation of the overall scheme |
| Description | the description of the object |
| Authorities | negotiations on consentability |
| Result | summarising the results |
The basic services include the cost calculation under DIN 276 and comparison against the cost estimate. That cost calculation is at the same time the basis of the entire fee.
This phase is the most important of the whole contract, not because of its weighting but because of its function. Since the 2009 revision the cost calculation model applies: the fee for all basic services is derived exclusively from the results of the cost calculation, exceptionally from those of the cost estimate.
Three consequences follow, and the third carries the furthest. It explains why a careful cost calculation is in the designer's own interest.
| Consequence | What follows |
|---|---|
| The cost calculation carries the whole project | the fee derived from it must cover the work through to phase 9 |
| Later cost increases do not raise the fee | where the project becomes more expensive without a change of scope, the fee basis stays unchanged |
| An understated allowance has lasting effect | no later cost determination can correct it |
The system is covered in the article on cost calculation at the third level. It also sets out which bases the standard requires at that level.
A point of classification: coordinating the work of other specialist designers has been a basic service of this phase since the 2013 version. It previously had to be agreed separately, which older templates still reflect.
The ratio of effort to fee
The three phases carry 24 per cent of the fee between them. Actual effort in many practices runs above that, and there are structural reasons.
| Cause | Effect |
|---|---|
| Advisory intensity in phase 1 | high time input against a 2 per cent weighting |
| Options investigation in phase 2 | effort beyond the scope owed |
| Iteration with the client | not weighted, since not carried as a service of its own |
| Preliminary discussions with authorities | scope depends heavily on the federal state |
| Coordinating specialists in phase 3 | a basic service since 2013, without the weighting being raised |
Two levers follow for contract drafting. First, the additional services likely to arise across this stretch should be listed with prices in the proposal, so that commissioning them later is a call-off decision. Second, since binding price law fell away, the distribution of percentages can be agreed differently, which makes sense on advice-intensive commissions.
Commissioning concept or developed design alone
One special case bears directly on this stretch: commissioning concept design or developed design as a standalone service, that is without the other phases. In invoicing it is regularly treated as an ordinary partial commission, which falls short.
The arrangement is common, for instance where a client needs a feasibility assessment before deciding on a site, or where a competition entry is to be developed further. In neither case is a continuation of the commission settled at the outset.
The HOAI provides a separate calculation rule for this, because a phase commissioned in isolation generates more effort than the same phase within a continuous commission. Familiarisation, establishing the basis and preparing the output all arise in full, whereas in a full commission they are spread across several phases.
For contract drafting it follows that a standalone commission should not be invoiced at the bare percentage of the phase. Separate remuneration for additional coordination or familiarisation effort must moreover be agreed in text form.
The transition between phases
The three phases build on one another, and each transition is a client decision. The cost determinations are the basis for it: the cost estimate serves the decision on concept design, the cost calculation the decision on developed design.
Beginning a phase before the preceding one has been approved creates a risk that may be attributed to the designer in a dispute. Approval should therefore be recorded, at least in text form.
The move from cost estimate to cost calculation is moreover more than an increase in accuracy; it changes the level of the cost structure and the data basis. The article on the transition covers it in detail.
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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.