Tendering and procurement under the VOB: a guide

Part	Governs	Operates	Binds
VOB/A	procurement	before contract	public clients
VOB/B	contract conditions	from contract	anyone incorporating it
VOB/C	technical conditions and measurement	from contract	anyone incorporating it

The last column contains the most frequently overlooked point. The VOB/A binds only public clients, because it is procurement law. The VOB/B and VOB/C operate in every contract incorporating them, including between private parties.

The VOB is moreover not a statute. It is prepared by a committee of representatives of public clients and the construction industry. For public clients the VOB/A becomes binding through budget law; the VOB/B and VOB/C become binding by agreement.

The branch on the three parts covers the system. It also sets out whom each part binds and whom it does not.

This is the central proposition of the subject. It is where a sound calculation separates from an assailable one.

The VOB/C comprises 65 standards published as DIN standards. It answers two questions the specification does not: what is included in the price and how measurement proceeds.

All standards share the same structure:

Section	Content	Part of contract
0	Guidance for preparing the specification	no
1 to 3	Scope, materials and components, execution	yes
4	Incidental and additional services	yes
5	Measurement and final account	yes

Section 4 shifts amounts without any item existing for them. What counts as an incidental service forms part of the contractual work even without mention and must be priced by the tenderer. What counts as an additional service belongs tendered as its own item.

Section 5 determines the quantity. Two measurements of the same element diverge considerably where the deduction rules are applied differently.

The branch on the VOB/C covers both in detail. It also sets out the hierarchy between the general and the trade-specific ATV.

The commonest error when checking an account is transferring one trade's rule to another. It is also the easiest to avoid, since a glance at section 5 settles it.

Threshold	Trades
deduct above 2.50 m² individual size	masonry, concrete including formwork, drylining, render, external insulation, joinery, painting, wallpapering
deduct above 0.10 m² individual size	tiling, screeds, floor coverings

The difference is a factor of 25.

Why anything is measured over at all has a pricing rationale: an opening reduces material and increases labour on reveals, corners, junctions and lintels. Measuring over is the flat compensation for that.

A point rarely stated and practically significant: towards a private client who did not themselves propose applying the VOB, the deduction rules are not readily applicable. Someone from outside the construction industry need not know a rule under which what was not built is paid for.

The article on the deduction rules covers the detail. It also explains why the rule is not self-evident towards private clients.

The VOB/A requires work to be described clearly and so exhaustively that all firms must understand it in the same sense and can price it reliably and without extensive preliminary work. Four separate requirements follow from that single sentence.

A duty to investigate is added on the client's side. All circumstances influencing pricing must be established and stated in the tender documents.

The prohibition on unusual risk supplements the principle. No circumstances may be imposed on the contractor over which they have no influence and whose effect they cannot foresee. Both elements must be present.

An allocation of risk by knowledge and influence follows. Construction method and normal price movement sit with the tenderer, ground conditions and the state of the existing fabric with the client.

Clauses departing from this routinely cost more than they save. They produce either risk premiums or ineffective terms. The branch on the specification covers the requirements.

	Bill of quantities	Performance programme
Design	prescribed by the client	put out to competition
Quantities	measured by the client	wholly or partly left open
Comparability	price comparison by item	comparison across concepts
Default	yes	exception

The bill of quantities presupposes a fully completed design. Where that is missing, provisional items and daywork arise, that is precisely what the VOB/A restricts.

One point links this subject to fee law: preparing a performance specification is in principle an additional service for the designer, but becomes a basic service where tendering actually proceeds functionally. The choice of tendering route therefore changes the designer's scope.

Two independent changes affect the year 2026. They pull in opposite directions, since one removes form and the other adds substance.

The EU thresholds have fallen. Since 1 January 2026 the figure for construction contracts is €5,404,000 net, previously €5,538,000. A reduction widens the reach of European procurement law. Adjustment occurs every two years on a purely arithmetical basis; the next falls on 1 January 2028.

Design services carry a considerably lower figure because they are services. A design commission therefore reaches the threshold well before the construction project it serves.

National thresholds have risen.

Route	Threshold since 2026
Direct award	€50,000
Negotiated procedure	€100,000
Restricted tendering without prior call	€150,000

The threshold for the negotiated procedure has risen tenfold. States and municipalities may set different figures.

The branch on the procurement procedure covers the routes and their conditions. It also carries the thresholds changed on 1 January 2026.

A purely terminological peculiarity produces errors with consequences. The VOB/A calls Freihändige Vergabe what the rules for supplies and services call Verhandlungsvergabe.

The same route is meant, but the admissibility conditions and thresholds of the two bodies do not coincide. Transferring one's figures to the other means choosing an impermissible route.

A further source of error lies in state law. It happens that a state procurement act refers to a long superseded edition of the VOB/A.

Since 1 July 2026 an act has been in force amending around 19 statutes with some 110 provisions. It applies above the EU thresholds and leaves the below-threshold regime untouched.

Its scope is frequently omitted from summaries: it governs procurement above the EU thresholds. For construction works the threshold is €5,404,000, so a substantial share of construction procurement is not directly caught.

The principal changes concern three areas. Two of them ease the procedure; the third weakens legal protection.

Area	Change
Lotting	receives its own provision and permits an exception for major infrastructure projects
Evidence of suitability	becomes staged, with primacy for the self-declaration
Legal protection	the suspensive effect of an immediate appeal falls away

The constitutionality of the last change is open and the subject of a reference. The article on the procurement acceleration act covers the detail.

After award the VOB/B applies. Its starting point is a peculiarity of the construction contract: the client can order changes unilaterally.

Three kinds of variation follow, with different conditions. Only one of them presupposes notice.

Case	Order required	Notice
Quantity variation above 10 per cent	no	as a rule not
Changed work	yes	price should be agreed in advance
Additional work	yes	yes, before execution begins

The first needs no order, because the claim follows from the remeasurement contract model itself. The third carries a genuine duty to give notice, most frequently neglected in practice.

For decades, carrying forward the tender build-up governed. A good price stayed a good price, a bad one stayed bad.

The Federal Court of Justice abandoned that rule in 2019 for excess quantities. What governs since are the actually necessary costs plus appropriate mark-ups.

Whether the same principles apply to changed and additional work has not been decided at the highest level. The prevailing view and the lower courts affirm it, because the wording coincides. Legal certainty does not exist.

The same recommendation follows for both sides: a variation agreement before execution is cheaper than the dispute afterwards, whatever price is agreed. The branch on the construction contract covers the system.

Handover triggers four consequences at once. They are reversal of the burden of proof, the start of limitation, payment falling due, and the passing of risk.

Two periods are worth knowing:

Handover must be carried out within 12 working days where the contractor requests it after completion.

The limitation period for defect claims on structures is 4 years under the VOB/B and 5 years under the statutory law of works contracts. Incorporating the VOB/B therefore shortens it by a year.

A formal requirement is added whose neglect is expensive: reservations as to known defects and contractual penalties must be declared by handover at the latest. For penalties the claim otherwise falls away entirely.

Every part converges on the same relationship. It links the quality of the description to the volume of variations.

An item missing 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.

Two rules follow that prevent most disputes. Both concern timing rather than content.

Completeness before accuracy. A slightly wrong quantity corrects itself through remeasurement; a missing item does not.

The effort of a complete specification is less than the price of the variations it prevents. That calculation almost always favours the client.

Transferring one trade's deduction rule to another. The difference between 2.50 and 0.10 square metres is a factor of 25.

Not checking section 4 of the relevant ATV. What counts as an incidental service must be priced even where the text omits it.

Using provisional items to cover incomplete design. The VOB/A restricts them expressly.

Transferring risk in blanket terms. That produces risk premiums or ineffective clauses.

Changing item numbers during the project. That breaks the chain from bill of quantities to final account.

Omitting notice for additional work. It costs nothing and governs enforceability.

Forgetting reservations at handover. For contractual penalties the claim falls away entirely.

Using sources without checking their date. Two reforms took effect in 2026 and the VOB/A is being adapted further.

1. Complete the design before the bill of quantities is prepared.
2. Use section 0 of the relevant ATV as a checklist for the particulars belonging in the tender documents.
3. Check section 4 so that additional services are provided for as their own items.
4. Take the units of measurement from section 5 rather than choosing them freely.
5. Name the governing editions of the VOB/A, VOB/B and VOB/C.
6. Include the equivalence clause wherever technical specifications are referenced.
7. Keep item numbers stable across the whole project.
8. Take measurements before closing up, jointly where possible.

The first governs all the rest. A bill of quantities cannot be better than the design it rests on.

The three parts of the VOB

• The VOB and its three parts
• VOB/A: structure and sections
• Agreeing the VOB/B as a contractual basis
• Above and below the EU thresholds

The specification

• The specification under the VOB/A
• Building a bill of quantities
• The performance specification
• Clear and exhaustive specification
• GAEB data exchange in tendering

The procurement procedure

• The procurement procedure for construction works
• Procurement routes and thresholds
• Suitability and self-declaration
• Checking and evaluating tenders
• The procurement acceleration act

The construction contract under VOB/B

• The construction contract under VOB/B
• Variations under § 2 VOB/B
• Handover and its effects
• Measurement and the final account under § 14 VOB/B
• Pricing a variation

VOB/C and measurement rules

• VOB/C: the measurement rules by trade
• DIN 18299: the general provisions
• Reading the trade-specific ATV
• Applying the deduction rules