HOAI Service Phase 6 - Tender Documents and Bills of Quantities for Construction Projects

Before a construction project can be built, it has to be priced. And before it can be priced, it has to be described with precision.

That is the role of HOAI Service Phase 6. It translates execution planning into tender documents, bills of quantities, coordinated interfaces, and a cost basis that construction companies can price from the same foundation.

For buildings, Service Phase 6 is commonly weighted at 10% of the HOAI fee share while Service Phase 7 accounts for 4%. That difference says something important: preparing the tender-ready project basis carries more formal weight than supporting the award decision itself.

Well-structured tender preparation gives project owners and project managers stronger cost visibility and more confidence in award decisions.

What Is HOAI Service Phase 6?

HOAI Service Phase 6 is the preparation of the tendering process. It follows execution planning and organizes the approved planning basis into documents that contractors can use for pricing, clarification, and bid submission.

Its core purpose is to prepare a tender package that gives project owners, project managers, and later contract partners a reliable basis for procurement and award decisions.

Before going deeper into the documents themselves, these are the key facts that define Service Phase 6.

Key Facts About HOAI Service Phase 6

Its place in the HOAI sequence is what gives Service Phase 6 its leverage.

Service Phase 6 in the HOAI Sequence

In Germany, the HOAI (Honorarordnung für Architekten und Ingenieure) structures architectural and engineering services for construction projects into nine service phases. Each phase prepares the foundation for the next step.

Service Phase 6 sits between execution planning and participation in the award process. This position is important because it connects the technical planning work with the commercial preparation needed for tendering.

The HOAI service phases are:

1. Basic Evaluation Phase
2. Preliminary Planning (Project and Planning Preparation)
3. Design Planning (System and Integration Planning)
4. Approval Planning
5. Execution Planning
6. Preparation of Contract Award
7. Participation in Contract Award
8. Project Supervision (Construction Supervision)
9. Project Support and Documentation

With this position clear, the next question is: what has to be ready at the end of Service Phase 6? A tender basis that can be priced, checked, and compared.

The Tender Basis Created in Service Phase 6

A strong tender package gives all bidding contractors the same scope, quantities, interfaces, and technical basis for pricing. This allows project owners and project managers to compare contractor proposals with fewer hidden assumptions.

At the end of Service Phase 6, the tender basis should answer four practical questions:

• What work is being tendered?
• How much of it is required?
• Which technical and contractual conditions apply?
• Where do responsibilities, interfaces, and bid packages begin and end?

This makes HOAI Service Phase 6 the point where technical planning becomes organized for procurement. The project scope is translated into a format that supports bid comparison, cost control, and the next step in the HOAI sequence: participation in the award process.

Once the documents are issued, they start shaping how contractors understand the project, calculate risk, and build their offers.

Why Service Phase 6 Shapes Cost, Scope, and Execution

A tender tells the market how to understand, price, and deliver the planned work.

That makes HOAI Service Phase 6 a decisive moment for project control. At this stage, the project team defines whether the planned work can move into procurement without avoidable uncertainty.

When the tender documents are issued, is the project scope clear enough to be priced, awarded, and later tracked?

Comparable Bids Need Comparable Scope

Bid comparability depends on a procurement basis that gives every contractor the same technical and commercial reference point. If the bill of quantities, project drawings, specifications, or interface descriptions leave room for interpretation, contractors fill the gaps in different ways.

One bid may include a certain interface. Another may exclude it. A third may price the uncertainty as risk.

The result can look like a competitive bidding process, while the contractor proposals are based on different assumptions.

• For project owners, this weakens the basis for award decisions.
• For project managers, it makes the handover into execution less stable.
• For cost consultants, it weakens the cost check because the tender basis no longer reflects a clearly measurable scope.

Cost Control Starts Before Contracts Are Awarded

Service Phase 6 is one of the last moments before procurement where cost control can still influence the scope prepared for tendering. The cost check shows whether that scope still fits the earlier cost estimation and whether the expected construction costs remain realistic before the contract sum is fixed.

This check becomes even more important when construction prices remain volatile. In Q1 2026, German construction price indices were still rising year over year for residential, office, and industrial buildings.

The cost impact is direct: bidding contractors price uncertainty as well as labor, equipment, and materials needed for the work. Unclear quantities, missing interfaces, or vague descriptions can increase risk buffers and affect the total cost of a construction project before work begins.

The effect continues into execution. Once contracts are awarded, the tender basis becomes a reference point for monitoring progress, identifying deviations, and coordinating work during the construction period.

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The official HOAI service structure shows how this tender-preparation work is defined in more detail.

6 Basic Service Blocks in HOAI Service Phase 6

In HOAI Anlage 10, Service Phase 6 is structured through basic services, the so-called Grundleistungen. These services define what architects and engineers must prepare before the construction project moves into bid evaluation and award support.

Service Phase 6 can be grouped into six service blocks:

1. Tender Schedule

The tender schedule is the timeline for preparing, reviewing, issuing, and receiving tender documents. It connects procurement preparation with the wider project schedule.

2. Service Descriptions

Service descriptions define the construction work that contractors are expected to price. They describe required performance, quality, execution requirements, and relevant technical conditions.

3. Bills of Quantities

The bill of quantities organizes the planned work into measurable items for tender pricing.

4. Quantity Takeoff

Quantity takeoff is the process of determining the quantities needed for tendering. It translates information from project drawings, specifications, and planning documents into measurable values.

5. Interface Coordination

Interface coordination clarifies where responsibilities between trades, bid packages, or technical systems meet. It reduces gaps between contractors before the work reaches the construction site.

6. Cost Determination and Tender Compilation

Service Phase 6 also includes determining and checking costs, preparing priced BOQs where required, and compiling the tender documents. This helps project owners and project managers review contractor proposals in the next HOAI phase.

Each basic service contributes to tender readiness. The bill of quantities deserves a closer look because it turns planned work into measurable, reviewable, and commercially usable scope. Few documents show tender readiness more clearly.

Bills of Quantities: Where Project Scope Becomes Measurable

A bill of quantities is a structured list of work items, quantities, units, and descriptions used in construction tendering. In German HOAI practice, it functions as the tender-ready schedule of works.

It is the document layer where planned construction work becomes measurable, reviewable, and ready for contractor calculation.

Why the Bill of Quantities Is Central to Tender Preparation

Project drawings and specifications describe the design intent. The bill of quantities tests whether that intent has been translated into measurable work.

This is where the quality of the previous planning becomes visible. A precise BOQ shows whether quantities are traceable, descriptions are clear, and technical requirements have been converted into tender-ready scope.

For project managers and cost consultants, the bill of quantities also makes the pricing structure easier to audit. It shows which work has been described, how it has been measured, and which assumptions sit behind the tendered scope.

10 Requirements for a Tender-Ready Bill of Quantities

A tender-ready bill of quantities should remove as much room for interpretation as possible. The goal is not more detail for its own sake, but enough structure for contractors to calculate, project teams to review, and later contract partners to manage the awarded scope.

It should include:

1. Work Item Description - The item should describe the work clearly enough for contractors to understand what is being priced.
2. Quantity - The quantity should be measurable and traceable to drawings, calculations, or other tender information.
3. Unit - The unit should match the type of work, such as m², m³, m, pcs, kg, or lump sum where appropriate.
4. Material Requirements - The BOQ should define relevant materials, product requirements, or quality expectations that affect pricing.
5. Execution Requirements - The item should include requirements that influence labor, method, access, sequencing, or installation quality.
6. References to Project Drawings - The BOQ should connect each item to the relevant project drawings, details, or technical documentation.
7. References to Project Specifications - Specifications should clarify performance standards, tolerances, finishes, or technical conditions.
8. Trade and Interface Boundaries - The BOQ should make clear where one contractor’s responsibility ends and another trade or bid package begins.
9. Assumptions and Exclusions - Important assumptions, exclusions, or scope limits should be documented so pricing is based on the same understanding.
10. Sufficient Detail for Review - The final structure should allow project teams to check whether the scope, quantities, and pricing basis are complete enough for tendering.

How Bills of Quantities Are Structured in Complex Projects

In smaller building projects, one BOQ may be enough. In larger or more complex projects, the structure often becomes part of the procurement strategy.

This structure helps project teams keep the bill of quantities aligned with the way the project will be procured, packaged, and later controlled.

In complex projects, a bill of quantities can be divided by:

• trade
• building section
• floor
• technical system
• bid package
• construction phase
• work sequence
• responsibility area

That structure becomes important once the bill of quantities has to support more than pricing alone.

How Bills of Quantities Structure Supports Project Control

Bill of quantities structure directly affects how easily project teams can compare prices, assign scope, review associated costs, and connect the awarded work with later contract management.

The key question is: can each part of the BOQ be priced, awarded, tracked, and checked without losing the connection to the overall project scope?

When the structure is clear, contractors, quantity surveyors, cost consultants, and project managers can understand how the work is divided and where each pricing responsibility sits. That makes the BOQ useful beyond tendering: it supports project monitoring, change control, and final account discussions later in the project lifecycle.

Bill of Quantities Example in Construction Tendering

A bill of quantities does not need to be complex to show its purpose. Even a simplified example makes the logic clear: the project is first divided into work packages, then into measurable line items with quantities, units, rates, and scope notes. This allows bidding contractors to price the same work in a structured way.

In real construction projects, a bill of quantities is usually more detailed than this example. It may include summary sheets, trade packages, material and labour rates, unit prices, remarks, exclusions, allowances, and specification notes. However, the principle stays the same - the clearer the measurable items, the easier it becomes to price, compare, and review the tendered scope.

Common Tender Preparation Risks in Service Phase 6

Service Phase 6 is formally about preparing the tender. In practice, it is also a critical risk-management point, because small gaps in the tender package can shape how contractors understand scope, calculate uncertainty, and prepare their offers.

A tender package may look complete at first glance. The real risk often sits deeper: in quantities that are hard to trace, interfaces that remain open, drawings and descriptions that do not fully align, or assumptions that are visible to one party but missing for another.

These details can influence project costs, complicate contract management, and make project monitoring harder once the work moves into the construction phase. Before release, the tender package needs one final question: is the scope clear enough to be priced, awarded, and later controlled without avoidable friction?

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Why do these risks travel so far? Because Service Phase 6 sits in the information flow between execution planning, award decisions, and construction supervision.

How Service Phase 6 Connects Service Phases 5, 7, and 8

Service Phase 5 provides the technical planning basis. Service Phase 6 translates it into tender-ready scope. Service Phase 7 uses that scope for bid evaluation and award decisions.

In Service Phase 8, the awarded scope becomes part of construction supervision: progress is monitored, changes are reviewed, and deviations are checked against what was tendered and contracted.

The smoother this information flow is, the easier it becomes to keep procurement, contract management, and project monitoring connected to the same scope.

How Digital Project Control Supports Tender Preparation

Tender preparation depends on information that is still changing until the tender package is ready for release. In Service Phase 6, digital project control helps teams keep those changes visible before they become part of bids, contracts, and construction control.

The value lies in visibility: which documents are current, which decisions are still open, who owns the next step, and how changes affect the project schedule.

Keeping Tender Information Traceable Before Release

For Service Phase 6, this is especially relevant because tender documents sit between planning and commitment. Once they move into bidding, they begin to shape contractor questions, award decisions, contract management, and later project monitoring.

A connected environment for digital project control can support this transition by keeping several elements visible in one central place:

• Document status and planning changes
• Responsibilities and decision ownership
• Deadlines for tender preparation and review
• Changes before tender package release
• Links between scope, schedule, and execution logic
• Handover information for tendering and construction execution

Making the Handover Easier to Control

After tender release, the same information starts to move through bidding, award, contracts, and execution. A controlled handover depends on keeping that information connected to the decisions, schedules, responsibilities, and changes that shaped it.

This is where Lcmd’s approach to centralized project management fits the Service Phase 6 context. Lcmd, short for Lean Construction Management Digital, connects planning, scheduling, responsibilities, BIM, reporting, and execution workflows in one environment.

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Construction management software adds a project-control layer around tender preparation, so information prepared for procurement remains usable during award, contract management, and later project monitoring.

For Lcmd, this is the connection between planning and delivery: keeping project information visible, traceable, and usable from tender preparation into execution.

Conclusion: Service Phase 6 Turns Planning Into a Tender-Ready Project Basis

A construction project does not enter the market as a drawing, a model, or an intention. It enters the market as a scope that contractors can understand, calculate, question, and eventually commit to.

That is why HOAI Service Phase 6 carries more weight than its position in the process may suggest. It gives planning a commercial form: structured enough for procurement, reliable enough for award decisions, and stable enough to support the next phase of delivery.

Before bidding begins, one question decides the quality of the handover: can the project move into the market without carrying hidden uncertainty into the contract and construction phase?

When the answer is yes, Service Phase 6 has created the conditions for a clearer, more controlled project start.

Checklist for a Tender-Ready Service Phase 6

Use this Service Phase 6 checklist to review your tender documents, bill of quantities, cost basis, and project scope before the bidding process begins.

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FAQs

How Much Is the Fee Share for HOAI Service Phase 6?

For buildings, HOAI Service Phase 6 accounts for 10% of the basic services fee share; for interiors, it accounts for 7%. These percentages apply to the HOAI service profile for buildings and interiors. Since the HOAI 2021 reform, the fee tables and shares serve as orientation values, while the exact compensation depends on the individual agreement, project scope, chargeable costs, and project parameters.

What Is the Difference Between Tender Preparation and Participation in the Award?

Service Phase 6 creates the tender-ready basis. Service Phase 7 uses it to evaluate bids, compare contractor proposals, answer bidder questions, and support the award decision.

What Role Does VOB Play in Construction Tendering?

VOB provides important rules and standards for construction tendering and construction contracts in Germany. In the context of HOAI Service Phase 6, it helps shape how tender documents, service descriptions, contractual conditions, and later construction work are structured. For project teams, the key point is simple: tender documents should be prepared in a way that supports clear, comparable, and contract-ready bids.

Who Is Involved in Service Phase 6 Besides the Architect?

HOAI Service Phase 6 often involves more than the architect because tender preparation depends on coordinated technical, commercial, and project-control input. Besides architects, the process may include project owners, project managers, the design team, cost consultants, specialist planners, and contract administrators.

Depending on the delivery model, construction managers or future general contractors may also provide input, especially where procurement strategy, buildability, or package structure needs early coordination.

Why Are Incomplete Bills of Quantities Risky for Project Owners?

Incomplete bills of quantities are risky because they make contractor bids harder to compare and weaken cost certainty before award. If quantities, descriptions, interfaces, or scope details are unclear, contractors may price different assumptions into their bids. This increases the risk of claims, change orders, cost deviations, delays, and disputes during construction.