HOAI work phases: fees and service profiles for architects

For the service profile covering buildings and interiors the percentages are as follows. Both columns total 100 per cent but distribute that total differently on four phases.

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, which most overviews omit. Applying the building figures to a pure interiors commission misallocates around a tenth of the fee.

Three observations about the distribution matter for contract drafting. Construction supervision carries almost a third at 32 per cent. All design up to consent carries only 27 per cent for buildings. And consent design at 3 per cent is strikingly low, although its effort depends heavily on the federal state and the procedure.

The branch on the nine work phases covers them in detail. It also sets out which basic services belong to each phase.

One point has direct consequences for invoicing and is frequently misunderstood: the HOAI weights work phases, not individual basic services. The phase is thus the smallest unit the ordinance weights.

Where not all basic services of a phase are transferred, only a fee corresponding to the share transferred may be charged. That share is not normed, however, but must be agreed in text form.

In practice, assessment tables from the professional literature are used. They are usable, but they are not requirements of the ordinance, and the source relied upon belongs in the contract.

Quantity	What it determines
Chargeable costs	the fee basis, from the cost calculation under DIN 276
Fee zone	the degree of difficulty, from six assessment criteria
Fee table	the fee band, interpolated where needed
Work phases	the chargeable share

The order is unavoidable. No chargeable costs, no table value; no zone, no band; no commissioned phases, no share.

The commonest error concerns the first row. Chargeable costs are not construction costs: cost group 300 counts in full, cost group 400 only up to a threshold of 25 per cent of the other chargeable costs and at half above it, cost groups 100, 700 and 800 not at all, and value added tax is expressly excluded.

The system of chargeable costs is covered in the subject area on cost planning under DIN 276, and the calculation in the branch on calculating fees. Both are needed, since neither quantity yields a result without the other.

A belief circulates that the fee zone is calculated through assessment points. The ordinance says otherwise.

The points method applies only where criteria from several zones are applicable and doubt therefore arises. In the normal case, allocation follows directly from the criteria and the object list.

The weighting is also notable: the number of functional areas and the design requirements each carry up to 9 points, half as much again as the other four criteria at up to 6 points each. The article on fee zones covers the procedure.

The basis is the judgment of the Court of Justice of the European Union of 4 July 2019, holding the binding minimum and maximum rates contrary to the Services Directive. The judgment concerned the rates themselves and not the rest of the ordinance.

Until end of 2020	Since 2021
Binding price framework	Free negotiation
Minimum and maximum rates	Fee tables as values for orientation
Minimum rate as a mandatory floor	Base fee rate as a fallback
Written form at commissioning	Text form, at any time

Nothing about the level of the fee remains binding. A fee above the former maximum can validly be agreed, as can one below the base fee rate.

Two formal requirements remained binding, and neglecting either leads to the base fee rate. Both concern the form of the agreement and not its level.

Without an agreement on the level in text form, the base fee rate applies to basic services as agreed. That fiction cannot be rebutted and applies towards all clients.

Without timely notice to a consumer in text form that a higher or lower fee may be agreed, a higher fee is capped at the base fee rate. The agreement remains valid, and the burden of showing compliance sits with the designer.

The two mechanisms are frequently conflated. The branch on fee agreements treats them separately.

This is the central insight of the subject. It moves the weight of contract work from the arithmetic to the description.

While the rates bound the parties, the argument was mostly about level: was the minimum rate observed, which zone applies, were chargeable costs correctly determined. Today the level is freely negotiable, and the dispute shifts to the question of what is owed for the amount agreed.

Two consequences follow that affect the whole of contract practice. They act in the same direction and reinforce one another.

The service profiles have become the most important normative reference. They are the only normed catalogue of what a work phase comprises, and they serve as the measure even under a lump sum fee. Legally they nonetheless remain no schedule of obligations: the HOAI is price law, and what is owed follows from the contract and from general contract law.

Text form has taken the place of price law. The ordinance requires it at a strikingly large number of points: for the level of the fee, for the notice to consumers, for partial commissions, for weighting incomplete phases, for the conversion supplement, for the increase on repair work, for adjustment on changes of scope, and for additional coordination effort. What is not agreed in text form follows either from a fallback operating against the designer, or not at all.

A reversal of priority follows for drafting: precisely describing the scope now matters more than deriving the amount. The amount is negotiable; the scope determines what it is paid for.

Projects in existing buildings generate more design effort than new build. The HOAI addresses this with three instruments operating side by side at different points.

Instrument	Acts on	Limit
Existing fabric incorporated	chargeable costs	none, to be appropriately taken into account
Fee zone	the applicable band of the table	five zones
Conversion supplement	the fee determined	up to 33 per cent for buildings, 50 for interiors

The order is not arbitrary: existing fabric acts before the table is read, the supplement afterwards. Omitting the fabric allowance therefore cannot be offset by a higher supplement.

A widespread misconception is to forgo applying the existing fabric and cover the additional effort through a higher supplement alone. That does not work arithmetically: the supplement acts proportionally on too small a basis, and it is capped in amount while applying the fabric is not.

Note too that the 20 per cent fallback where no agreement exists applies only from an average degree of difficulty. Below that, no supplement arises absent agreement. The article on the conversion supplement covers how they interact.

The default in the ordinance is a commission covering all nine phases. The default in practice is different.

Where not all phases are transferred, only the percentages of those transferred may be charged, and the agreement must be in text form. A commission to consent gives 27 per cent for buildings; a commission for supervision alone gives 32 per cent.

Economically, a partial commission at the bare percentage is routinely under-recovered. The rates reflect the average effort of a phase within a full commission; on an isolated commission, set-up, output preparation and interface coordination all arise in full.

The ordinance names an anchor for this that is almost never used: separate remuneration for additional coordination or familiarisation effort, to be agreed in text form. The article on partial commissions covers the arrangements.

In practice fees are lost less often through reduction than through failure to fall due. An account the client cannot check does not make the claim smaller, but it does make it unenforceable.

The fee falls due only once the work has been accepted and a verifiable final fee account has been handed to the client. An account that cannot be verified does not reduce the claim; it makes it unenforceable.

Conversely an obligation falls on the client: considering an account unverifiable, they must object and state concretely why they cannot follow it. A blanket assertion does not suffice.

Note that a substantial part of the case law on verifiability dates from the era of binding price law. Its core applies unchanged, but everything attaching to the binding nature of the rates must be examined for transferability. The article on the verifiable final account covers the structure.

The ordinance is price law, not a law of obligations. A series of central questions is left open and follows from the contract, general contract law, state law or procurement law: what result is owed, who is liable for design errors, when the contract may be terminated, who holds copyright, who may submit building applications.

A territorial limit is rarely named: the HOAI applies only to service providers established in Germany whose services are additionally provided from within Germany. For cross-border arrangements its application is a matter of agreement.

The branch on scope covers these limits. It also sets out which services the ordinance does not reach at all.

A revision process has been running for several years. Two expert reports exist, one on the service profiles and one on fee levels, and they propose substantial increases to the table values.

At the date of checking no draft ordinance existed; the formal procedure had not begun. The article on the HOAI reform gives the position and is the fastest-ageing article in this subject.

Two things follow for practice: the table values date in amount from 2013, which weakens a bare reference to the table as an argument. And a sound derivation of actual effort retains its value whatever the outcome.

The work phases describe the sequence, not responsibilities. On a typical building project several parties are involved, whose fees follow their own service profiles.

Role	Service profile	Reference quantity
Lead designer	buildings and interiors	chargeable costs under the threshold rule
Structural engineer	structural design	55 per cent of the fabric and 10 per cent of the technical installations
Building services designer	building services	chargeable costs of the installation groups
Landscape designer	open spaces	chargeable costs of the external works

The second row illustrates a point that illuminates the whole system: chargeable costs are not a property of the building but a property of the particular design service. The same building produces a different fee basis for each party.

A timing conflict also bears on collaboration: the cost calculation is to be prepared in work phase 3, while specialist design is in practice frequently commissioned only after work phase 4. A substantial part of the cost group 400 figures then comes from benchmarks, which tends to understate the allowance and acts twice over through the threshold rule.

The overview of profiles is covered in the article on the other service profiles. It also sets out why the percentages cannot be transferred between them.

Confusing construction costs with chargeable costs. The client names the construction sum; the fee basis is something else.

Applying the building rates to interiors work. Four phases diverge.

Treating the points method as the standard route. It applies only in cases of doubt.

Not making the agreement in text form. The base fee rate then applies, and the fiction cannot be rebutted.

Omitting the notice to consumers. A higher fee is capped at the base fee rate.

Forgoing the existing fabric allowance. A higher conversion supplement does not compensate.

Performing additional services without prior agreement. The entitlement exists but is hard to enforce.

Using sources without checking their date. A substantial share of available material describes the position before 2021.

1. Describe the scope, through the work phases, expressly naming departures and additional services.
2. Agree the level in text form, with a recorded derivation.
3. With consumers, give the notice first, in text form and demonstrably before their binding contractual declaration.
4. In existing buildings examine all three instruments, that is fabric, zone and supplement, agreeing each separately.
5. Regulate a change procedure, including the cases the ordinance does not cover.
6. Regulate dates, since the HOAI is silent and supervision effort grows with the construction period.
7. Price additional services in advance, so that commissioning them later is a call-off decision.
8. Build the final account in the order of the calculation, so that it can be verified.

The second and third points together take a few minutes and prevent both routes leading to the base fee rate. They are the most economical precaution in this entire subject.

The nine work phases

• The nine work phases of the HOAI at a glance
• Work phases 1 to 3: from brief to design
• Work phases 4 and 5: consent and detailed design
• Work phases 6 and 7: preparing and assisting procurement
• Work phases 8 and 9: supervision and aftercare

Calculating the fee

• Calculating fees under the HOAI
• Fee zones and assessment points
• Fee tables and the base rate
• Partial commissions by work phase
• Hourly rates and lump sum fees
• Calculating a fee: a worked example

Contract and remuneration

• Fee agreements since the 2021 reform
• The end of binding minimum rates
• Additional services under the HOAI
• Conversion supplement and fees in existing buildings

Adjustment and disputes

• Fee adjustment and avoiding disputes
• Changes of scope and fee adjustment
• Building a verifiable final fee account
• Repetition reduction for similar projects

Scope and outlook

• Scope and limits of the HOAI
• What the HOAI does not govern
• The other service profiles
• The HOAI reform: current status