The eight first-level cost groups
| Cost group | Designation |
|---|---|
| KG 100 | Grundstück (site) |
| KG 200 | Vorbereitende Maßnahmen (preparatory works) |
| KG 300 | Bauwerk Baukonstruktionen (building fabric) |
| KG 400 | Bauwerk Technische Anlagen (building services) |
| KG 500 | Außenanlagen und Freiflächen (external works and open spaces) |
| KG 600 | Ausstattung und Kunstwerke (furnishings and artworks) |
| KG 700 | Baunebenkosten (ancillary construction costs) |
| KG 800 | Finanzierung (financing) |
From these the standard defines two aggregate terms, constantly used and constantly confused. Their difference governs the comparability of every benchmark.
- Bauwerkskosten, building cost, is the sum of cost groups 300 and 400.
- Gesamtkosten, total cost, is the sum of all cost groups from 100 to 800.
The large majority of published cost benchmarks refer to building cost. Reading such a figure as the construction sum understates the budget considerably. The system is covered in what a construction cost benchmark includes.
The three levels and their numbering
Every cost group is subdivided across three levels, and the numbering follows a simple logic. It can be read off any group.
The first level is the hundreds digit, that is the eight groups above.
The second level is the tens digit. KG 100 Grundstück thus becomes 110 site value, 120 acquisition costs and 130 third-party rights.
The third level is the units digit. KG 120 acquisition costs becomes 121 surveying fees, 122 court fees, 123 notary fees and others.
Two peculiarities matter. First, the numbering is not continuous: gaps exist, and not every conceivable position is occupied. Second, every group ends with a position x90 Sonstige Maßnahmen, other measures, serving as a catch-all.
The x90 positions deserve particular attention. They are intended for costs belonging to the group in substance but not attributable to any of the positions provided. In practice they are frequently used as a repository for anything troublesome. A cost determination with conspicuously large "other" positions regularly signals unfinished allocation and is hard to explain to a client.
Which level is required when
The required depth of treatment rises with design progress. It is fixed separately for each stage of cost determination.
| Stage of cost determination | Level |
|---|---|
| Kostenrahmen | first |
| Kostenschätzung | second |
| Kostenberechnung | third |
| Kostenvoranschlag | third, additionally by procurement package |
| Kostenanschlag | by procurement package |
| Kostenfeststellung | third |
The requirements for the cost estimate and cost calculation were each deepened by one level with the 2018 edition. Older templates and software defaults still carry the earlier requirements. The system of stages is covered in the branch on the stages of cost determination.
What changed with the 2018 edition
Four changes act directly on allocation.
Cost group 800 Financing is new. Financing costs were removed from cost group 700. Anyone calculating on older rules of thumb and expecting financing within ancillary costs drops it without noticing.
Cost groups 300 and 400 now apply uniformly to building construction, civil engineering and infrastructure. The formerly separate standards were consolidated.
Cost group 500 was extended. It now covers both external works belonging to buildings and open spaces independent of any building.
Over 240 cost groups were reworked, some redrafted, some renamed, some moved between groups.
The last change is the quietest and the most consequential. It affects in particular the boundary between building fabric and technical installations, and that boundary governs application of the special rule for services within chargeable costs. The coexistence of editions is covered in the version problem.
The four deeper articles in this branch
Cost group 300 covers the building fabric from excavation to roof. It is the largest group and carries the greater share of building cost. Covered in KG 300 building fabric.
Cost group 400 covers the technical installations. Its share of building cost has risen steadily. Covered in KG 400 building services.
Cost groups 100 and 200 concern the site and its preparation. They sit outside building cost and are covered in KG 100 and KG 200.
Cost groups 500 to 800 cover external works, furnishings, ancillary costs and financing. Covered in KG 500 to KG 800.
The most common allocation questions
The boundary between building and external works. What governs is whether an element is connected to the building. Roof, facade and interior planting belonging to the building count within cost group 300. External works outside the building and designed open spaces count within cost group 500.
The boundary between fabric and technical installations. This is the most fee-relevant allocation question of all and is covered in the two deeper articles.
Strip-out in conversion work. In conversions and modernisations, partial demolition, repair, temporary support and dismantling belong to the cost groups affected and are shown there. They form no group of their own but follow the element on which they take place. Full demolition of a building, by contrast, belongs to the preparatory works.
Utility connections. Connection runs for water, drainage, electricity, gas and telecommunications belong to the respective technical installations in cost group 400. Public servicing and the charges for it belong in cost group 200.
The cost groups as a tool for cost management
The structure serves not only order but management. Its real purpose is to make cost shifts between groups visible and therefore open to discussion.
An example from early design: heavier insulation of the envelope raises cost group 300 while reducing the effort for heat supply in cost group 420. A more elaborate ventilation system raises cost group 430 and may reduce requirements on the facade.
Such shifts can only be assessed where the structure is fine enough. At the first level they are invisible, because movements within building cost cancel out. Only at the second and third levels does it become apparent which group a decision burdens and which it relieves.
That is the substantive reason behind the deepening of the required treatment in 2018. A cost estimate at the first level supports a statement about order of magnitude but no appraisal of options.
A terminological clarification
The standard designates cost group 400 as Bauwerk Technische Anlagen. In practice and in many sources it is referred to as technische Gebäudeausrüstung, abbreviated TGA.
Both terms mean the same thing in everyday use, but they are not congruent: since 2018 cost group 400 applies uniformly to civil engineering and infrastructure works too, for which "building services" does not fit. In a cost determination the designation of the standard is therefore the one to use.
Related articles
This article reflects the position at the date of checking and serves professional orientation. It does not constitute legal advice and does not replace assessment of the individual case.