Which cost determinations are basic services and which are not

For the service profile covering buildings and interiors, the picture is as follows. It separates basic services from additional ones.

Three stages are therefore unambiguously basic services: the cost estimate, the cost calculation and the final cost statement. Two lie outside, and one is a special case.

The Kostenrahmen arises during briefing, that is before or at the start of the initial appraisal. It serves the client as the basis for deciding on the project itself.

The HOAI does not list it as a basic service. Where the designer is expected to provide it, it must be agreed as an additional service and remunerated separately.

This is economically awkward, because the cost framework is simultaneously the most consequential cost statement of the entire project: it is later used as the yardstick, even though it arises on the thinnest data. Providing it free of charge means taking on risk without consideration.

Here the two systems diverge most clearly. DIN 276 introduced the Kostenvoranschlag with its December 2018 edition. It is determined on the basis of construction preparation and serves to prepare procurement.

The HOAI in its 2021 version does not recognise it as such. For work phase 6 it instead provides for preparing priced bills of quantities. The two overlap in substance but are not identical, and the pre-tender estimate within the meaning of the standard is not a basic service.

The reason is simply chronological: the HOAI version establishing these service profiles predates the reissue of DIN 276. The standard developed; the ordinance did not follow. The stage itself is covered in the article on pre-tender estimate and tender sum.

The most consequential rule on this topic concerns not which determination is owed but which one sets the fee. It concerns the fee basis of the entire commission.

Since the 2009 revision the so-called cost calculation model applies. Under it, the fee for all basic services within a service profile is derived exclusively from the results of the Kostenberechnung, exceptionally from those of the cost estimate. It replaced the earlier stage-by-stage accounting.

Three consequences follow that are routinely underestimated in practice. All three concern the timing of the cost calculation.

The cost calculation carries the whole project. The fee derived from it must cover the practice's work across the full project duration, including work phases 5 to 9, which fall long after it.

Later cost increases do not raise the fee. Where the project becomes more expensive during construction without any change of scope, the fee basis stays the same. The final cost statement is a basic service, but it is not the basis of fee determination.

A cost calculation set too low has lasting effect. It cannot be corrected by later determinations. Where scope changes by agreement and chargeable costs change as a result, a written agreement on adjusting the fee calculation is provided for.

The cost calculation is therefore the single most important cost determination of the project, not because of its accuracy but because of its function. Its result carries through to work phase 9.

What is owed as a basic service is a cost calculation meeting the requirements of the ordinance. The HOAI requires it to be prepared on the basis of DIN 276 to at least the second level of the cost structure.

Everything beyond that is an additional service to be agreed and remunerated separately. This includes in particular: Absent an agreement there is no entitlement to payment.

• the deepened cost calculation by individual items, lead items, execution types or single building elements
• structuring by additional ordering criteria, such as by procurement package alongside the element structure
• cost determinations for options going beyond the appraisal owed
• rolling cost forecasts beyond the cost control contractually owed

Worth noting is the discrepancy with DIN 276, which provides for the cost calculation to be worked to the third level. Anyone calculating to the third level in conformity with the standard potentially delivers more than the basic service requires. That question belongs before contract, not in the final account.

Alongside the cost determinations, the service profiles oblige the designer to carry out continuous cost control. It appears in several work phases as a basic service, particularly as a comparison of the current determination against its predecessor.

What is notable is that cost control is not itself a stage of cost determination. It is an activity taking place between the stages and depending on their comparability.

A practical requirement for how determinations are built follows: they must be structured so that comparison across the stages remains possible. Where the structure changes between two stages, for instance from an element structure to a structure by procurement package, cost control can no longer be performed without a reconciliation.

How cost control is built and how it relates to cost management is covered in the branch on cost control and cost management. It also sets out how late an intervention can still have effect.

Four points should appear in the contract and rarely do. They take a few lines to draft.

1. Which cost determinations are owed, expressly named, including those that are not basic services.
2. At what depth of detail they are to be prepared, stating the level of the cost structure.
3. Under which edition of DIN 276 determination proceeds, separately for cost planning and for chargeable costs.
4. How changes of scope and consequent changes to chargeable costs are handled.

The second point causes disputes more often than the first. Considerable effort separates a cost calculation at the second level from one at the third, and both carry the same name.

• Chargeable costs under DIN 276 and the HOAI
• Pre-tender estimate and tender sum distinguished
• Cost calculation at the third level of the cost structure
• Cost framework and cost estimate: the early stages
• HOAI work phases