Pillar article
Leistungsphase 8: construction supervision and documentation — the complete guide
Service phase 8 ('Leistungsphase 8') of the German HOAI carries 32% of the fee points, making it the weightiest service phase — and the one with the highest liability risk. What isn't documented here can hardly be proven later.
Expert article by Open Experience GmbH. · As of: July 2026
What is Leistungsphase 8?
Leistungsphase 8 under the HOAI (the German fee and service structure for architects and engineers; "Objektüberwachung — construction supervision and documentation") is the eighth of nine service phases. In it, the site supervisor monitors the construction work for conformity with the permit, the execution planning, the service specification, and the recognized rules of technology, coordinates the parties involved, identifies defects, assists with acceptance, and documents events on the construction site. For buildings and interiors it accounts for 32% of the fee — more than any other phase.
Which basic services does service phase 8 include?
The HOAI (Annex 10, service profile for buildings) lists eleven basic services. Here they are, together with what makes them fail in practice — and what has to be documented.
| Basic service | What it requires | What has to be documented |
|---|---|---|
| Supervising execution | Conformity with permit, plans, service specification, and the rules of technology | Site walks with date, location, and photo — especially before building elements are closed up |
| Coordinating the parties | Aligning the technical parties involved in site supervision | Meetings, instructions, directives with date and addressee |
| Keeping the site diary | Continuous documentation for every working day | Weather, companies, headcount, work performed, disruptions, occurrences |
| Joint measurement | Quantity measurement together with the executing companies | Measurement sheets confirmed by both sides |
| Identifying defects | Detect defects, notify them, set a deadline, supervise remediation | Defect with photo and location, receipt of the notice, deadline running, clearance report |
| Assisting with acceptance | Recommend acceptance, prepare and accompany the formal acceptance | Report with reservations, defects, and deadlines |
| Invoice verification | Technical and arithmetical review of contractor invoices | Verification notes referencing measurements and work progress |
| Cost control and cost determination | Monitoring per DIN 276 | Cost figures with date and source |
| Organizing handover | Handover of the property, applications for official approvals | Handover report, as-built documents, official notices |
| Listing limitation periods | Compiling the deadlines for defect claims | Deadline list per trade with start and end |
| Supervising defect remediation | Overseeing remediation of defects identified at acceptance | Extended deadlines, evidence, acceptance of the rework |
Source: HOAI, Annex 10 (service profile for buildings and interiors), § 34.
The site diary obligation — what has to be documented
The site diary is a basic service of service phase 8: the site supervisor must document construction progress continuously — customarily date, weather, companies present and headcount, work performed, deliveries, disruptions, instructions, and special occurrences. If the site diary is missing, a fee reduction and a lack of evidence loom.
What matters is continuity: a diary reconstructed weeks later loses its evidential value — exactly what courts and experts check first.
Defect management in service phase 8
The site supervisor must identify defects, document them, notify the contractor with a deadline for remediation, and supervise the remediation — before, during, and after acceptance.
- The chain of evidenceDefect with photo and location → receipt of the defect notice → deadline running → rework → clearance report. If one link breaks, the defect is hard to enforce in a dispute.
- Typical mistakesCollective complaints without individual attribution, missing proof of receipt, notices without a specific deadline.
- Legal basisDefinition of a defect per § 633 BGB (German Civil Code) and § 13 VOB/B.
Acceptance — BGB and VOB/B
Acceptance is the most important legal moment of the construction contract: it starts the limitation period for defect claims, reverses the burden of proof, and makes the contract price due. The BGB recognizes, among others, express, implied, and deemed acceptance (§ 640 BGB); the VOB/B (German construction contract procedures) adds the formal acceptance (§ 12 VOB/B) — the standard in professional construction.
Rule of thumb for the walkthrough: reservations must be declared expressly — known defects and the contractual penalty. Whoever fails to record them loses them.
Warranty — deadlines and follow-up after acceptance
Under the BGB, defect claims for buildings become time-barred after five years, under VOB/B after four years (each from acceptance; deviating agreements are possible). Service phase 8 requires listing the limitation periods and supervising the remediation of defects identified at acceptance — in practice the most frequently neglected basic service.
- Suspension through defect noticeUnder § 13 (5) VOB/B, a written defect notice extends the limitation period for the notified defect.
- Organization over yearsWarranty keeps running when the project team has long moved on — which is why it belongs in a system, not in an Excel file on a network drive.
Liability — why service phase 8 is the most dangerous phase
The site supervisor is liable for supervision errors. Because construction defects often only surface years later, today's documentation decides tomorrow's lawsuit: whoever cannot prove supervision and documentation loses — regardless of how well they actually supervised.
- Typical liability casesFailure to supervise supervision-intensive trades, a missing site diary, missed deadlines.
- Joint and several liabilityThe site supervisor is often liable alongside the executing company — recourse is a second lawsuit.
- Fee versus risk32% of the fee stands against a disproportionate risk. Documentation is the cheapest insurance.
Delivering service phase 8 economically — analog versus digital
The documentation duties of service phase 8 can hardly be fulfilled economically anymore with notepad, camera, and Excel: every piece of information is handled multiple times — captured on the construction site, typed up in the office, formatted in the report. Digital construction documentation captures defect, photo, location, and responsible party in one step and generates reports automatically.
"For us, the current challenges of Leistungsphase 8 are no longer conceivable without the services of OpenExperience." — Ingenieurgesellschaft Burgert mbH
Frequently asked questions
What percentage of the fee is attributable to service phase 8?
For the service profile buildings and interiors, 32% — the largest share of all nine service phases (§ 34 HOAI).
Is the site diary mandatory?
As a basic service of service phase 8: yes. Whoever fails to keep it risks a fee reduction and evidential disadvantages in a dispute.
When does the warranty period begin?
With acceptance. From then on, five years run for buildings (BGB) or four years (VOB/B).
What is the difference between the construction manager and the site supervisor?
The site supervisor delivers service phase 8 under the HOAI for the client; the responsible construction manager under the state building code bears public-law responsibility. The roles can, but need not, coincide.
Does the site supervisor have to be on the construction site at all times?
No — but for supervision-intensive trades (waterproofing, for example) the duty intensifies. Case law expects presence according to criticality, not according to the calendar.
How do I document service phase 8 work in an evidence-proof way?
Continuously, promptly, with timestamp, location, photo, and responsible party — and in a way that keeps the chain unbroken all the way to a dispute. That is exactly what digital construction documentation is built for.
Documentation that happens along the way.
In 45 minutes we'll show you how site diary, defects, acceptance, and warranty come together in one tool.