Work phase 4: consent design
Weighting: 3 per cent for buildings, 2 per cent for interiors.
This phase covers preparing and compiling the submissions and evidence for public law consents or approvals, lodging the documents, and supplementing and adapting the design documents and evidence. The catalogue is short; the effort behind it is not.
The low weighting is the most striking point in the whole service profile, and it sits in tension with actual effort. Four factors drive that effort without appearing in the weighting.
| Cost driver | Effect |
|---|---|
| The federal state | each state has its own building code with the force of statute; procedures differ down to their names, and so does the volume of documents |
| The procedure | exemption, simplified and full procedures generate very different effort; special building types bring their own ordinances |
| The building class | governs the requirements for fire safety and certification and hence the volume of specialist input |
| The number of parties involved | heritage, nature conservation, neighbours and public bodies can multiply the coordination effort |
Work phase 5: detailed design
Weighting: 25 per cent for buildings, 30 per cent for interiors.
Detailed design covers working up the solution ready for construction, drawn presentation of the object with all information necessary for construction, preparing the basis for the other specialist designers and integrating their contributions, and updating the detailed design during construction. The last item reaches into the construction period and does not end at award.
It is the heaviest design phase and the point at which the quality and economy of the eventual construction are decided. Incomplete detailed design generates variations, and on a scale that routinely exceeds the effort of completing it.
For interiors it weighs still more heavily at 30 per cent. The reason is substantively plain: a pure interiors commission avoids large parts of the consent and procurement work while demanding more detailing.
A point of classification: updating the programme was brought into the basic services of this phase with the 2013 version, as was updating the detailed design during construction.
The order is not always the order of the numbers
A practical point rarely found in overviews: phases 4 and 5 frequently run in parallel or overlap. The numbering describes a logic, not a sequence.
Once the consent documents are lodged, detailed design begins while the procedure is still running. That is customary and economically sensible, but it carries a risk: conditions attached to the consent can force changes to work already done.
Two precautions reduce that risk, and both belong in the contract rather than in a verbal understanding. They cost nothing to prepare.
| Precaution | Content |
|---|---|
| Recorded client approval | for starting detailed design early, including acknowledgement of the risk |
| Contractual provision | on how additional effort arising from consent conditions is handled |
Without both, the designer bears a risk they did not create. The condition comes from the authority, the extra effort stays with the practice.
Detailed design is the lever against variations
The economic core of this stretch lies in a relationship clients rarely see early enough: the extent of the detailed design determines the extent of later variations. What is not designed here is negotiated later.
An item missing from the bill of quantities, or unclearly described, is not tendered, not priced and not ordered. It appears during construction as a variation, at a point when competition no longer exists.
An argument follows that is rarely made in fee negotiations and that holds: cutting the detailed design reduces the fee by a fraction of the variation exposure it creates. Transferring detailed design to the contractor is, economically, transferring authority over the detail to the party that benefits from variations.
On the cost side, the article on cost management covers the relationship between depth of design and cost certainty. That article also explains why the room for management is practically closed after award.
The transition to procurement
Detailed design is the basis for the bills of quantities and therefore for procurement. Between the two lies a change of ordering: design proceeds by element, tendering by trade.
That change also acts on cost planning, because from the pre-tender estimate onwards ordering additionally proceeds by procurement package. The system is covered in the article on trade-oriented cost structure.
The procurement phases themselves are covered in the article on work phases 6 and 7. That article also sets out how the weighting of those two phases differs between buildings and interiors.
What to watch on partial commissions
This stretch is where partial commissions most frequently occur. Two arrangements are common.
| Situation | What it means | Chargeable |
|---|---|---|
| Commission up to work phase 4 | the client has the consent prepared and awards the later phases to a contractor or another designer | 27 % for buildings |
| Commission without work phase 5 | detailed design goes to the contractor; permissible, but it shifts responsibility for the detail solution | the remaining phases |
In both cases only the percentages of the phases transferred may be charged, and the agreement must be in text form. The system is covered in the article on partial commissions.
Related articles
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.