KG 500 to KG 800: external works, furnishings, ancillary costs, financing

The structure deliberately mirrors cost groups 300 and 400: earthworks, foundations, construction, technical installations. Anyone comfortable with the building groups finds their way here immediately.

The 2018 edition extended this group. It now covers both external works belonging to buildings and open spaces that are independent of any building. Landscape projects without an associated building can therefore be carried within the same system.

The dividing line with cost group 300 runs at connection to the building. Roof, facade and interior planting belonging to the building count within cost group 300; designed open spaces outside it within cost group 500.

Cost group 500 is conditionally chargeable, namely for landscape design commissions or where the building designer designs it alongside. Whether it is designed alongside is therefore a contractual question rather than a cost question.

Cost group 630 was newly introduced with the 2018 edition. It covers servers, computers, peripheral devices and accessories. Its introduction illustrates how the standard responded to a shift in building practice: information technology was previously captured either within technical equipment or not at all, depending on interpretation.

The decisive boundary of this group runs to cost group 400. What is permanently joined to the building belongs to the technical installations; what is movable belongs to furnishings. A fixed commercial kitchen installation belongs to cost group 470, a freestanding cupboard to cost group 610.

Cost group 600 is conditionally chargeable, namely to the extent the designer provides design services for it. Procurement of equipment by the client alone triggers no chargeability.

Two groups were fundamentally redistributed with the 2018 edition. The former cost group 730 was called architect and engineer services, the former 740 surveys and consultancy. Both were dissolved and redistributed into 730 lead design and 740 specialist design.

The new logic therefore orders by the kind of design rather than by profession or type of service. The change is substantial in practice: a survey that formerly landed routinely in cost group 740 today falls, depending on its subject, either into specialist design in 740 or into general ancillary costs in 760.

Cost group 700 is not chargeable. The designer does not include their own fee within the basis on which that fee is calculated.

Percentages and their base are covered in the article on ancillary construction costs under KG 700. That article also explains why a percentage without its stated base is unusable.

This group is new with the 2018 edition. Financing costs were previously part of cost group 700.

The separation is substantively right, since financing costs are neither design nor construction services and depend on interest levels and construction period rather than on the project. But it creates a recurring gap: anyone calculating on older rules of thumb and expecting financing within ancillary costs drops it without noticing.

Cost group 800 is not chargeable. It belongs in the client's total investment, not in the basis on which fees are calculated.

Cost group 830, interest on equity, is worth noting. It captures the imputed cost of the equity deployed, an item for which no invoice exists. It is almost never allowed for in practice but belongs in a complete viability appraisal, because the equity tied up would earn a return elsewhere.

All four groups share one property: they barely appear in drawings at early design stages and are therefore rarely quantified. Anyone who draws only what they see misses them entirely.

External works exist at the time of the cost estimate mostly as an area rather than a design. Their extent nonetheless follows from the site and the use and can be assessed early. On projects with vehicle movement, such as in commerce or logistics, paved areas can reach the scale of the building footprint.

Furnishings are frequently regarded as the client's affair and left out. For the total investment they are not, and in use-specific buildings they form a substantial block.

Ancillary construction costs are applied as a lump percentage without the base being stated. The fees within cost groups 730 and 740, by contrast, can be assessed early once chargeable costs and fee zone are approximated, and that is considerably more robust than any flat rate.

Financing is regarded as the bank's affair and does not appear in the cost determination at all. On long construction periods in existing buildings it is nonetheless a growing item, since interest accrues across the whole construction period while no return is yet generated.

In German public sector building, cost groups 200, 500, 600 and 700 together are applied as an uplift in the order of 33 % on top of building cost. The figure is an orientation for the early phase and does not replace a separate determination.

That magnitude is an orientation value rather than a rule of calculation. It shifts considerably with the site situation, the extent of external works and the depth of design. A greenfield project with extensive servicing and an infill scheme with minimal external works sit far apart at identical building cost.

A simple rule follows for cost determination: these groups are determined individually rather than applied as a percentage. Where a percentage must be used at an early stage, it belongs in the same line as its base, so that the assumption remains checkable later.

Conditional chargeability is a contractual question. Whether the building designer also designs the external works and the furnishings belongs in the agreement rather than in a later argument about the final account. The system is covered in the branch on chargeable costs.

• The cost groups of DIN 276 at a glance
• KG 100 and KG 200: site and preparatory works
• Chargeable costs under DIN 276 and the HOAI
• Basic services versus additional services
• Ancillary construction costs under KG 700