The structure
The VOB/C comprises 65 ATV standards, published as DIN standards. One of them applies to every trade, the rest to one each.
| Standard | Content |
|---|---|
| ATV DIN 18299 | general provisions for construction work of every kind |
| ATV DIN 18300 to 18459 | the standards for individual trades |
DIN 18299 applies to all construction work, including work for which no trade-specific standard exists. It is the general part, and the absence of a specific ATV never displaces it.
The trade-specific ATV contain detailed requirements per trade, from earthworks to building services. They establish what normal technical execution looks like in that trade, and their content counts as a recognised rule of technology.
Every ATV shares the same structure
This is the most practically useful point: all VOB/C standards are identically structured. Anyone who can read one ATV can read them all.
| Section | Content |
|---|---|
| 0 | Guidance for preparing the specification |
| 1 | Scope |
| 2 | Materials and components |
| 3 | Execution |
| 4 | Incidental services and additional services |
| 5 | Measurement and final account |
Two of the six sections are decisive for cost work. They answer the two questions the specification leaves open.
| Section | Content | What it decides |
|---|---|---|
| Section 4 | separates incidental services, which form part of the contractual work even without mention, from additional services, which are separately payable | what an item must cover and what must be tendered as a separate item |
| Section 5 | the rules on measurement and the final account, particularly the deduction rules | which openings and recesses are deducted and which are measured over |
The structure of the ATV in detail is covered in the article on reading the trade-specific ATV. It also sets out the order in which the sections should be read for each occasion.
Which standard prevails
On conflict between DIN 18299 and a trade-specific ATV, a clear hierarchy applies. Divergent provisions in ATV DIN 18300 onwards take precedence, so the check always begins in the trade.
That is more than a formality. It means the general deduction rules of DIN 18299 may be displaced within any trade, and that checking a final account therefore always involves two steps: consulting the trade-specific ATV and, only where it is silent, falling back on DIN 18299.
The general provisions are covered in the article on DIN 18299. Measurement is covered in the article on the deduction rules, including the thresholds that differ by trade.
Section 0 does not become part of the contract
One point is regularly overlooked and substantial for tendering. It concerns section 0 of the ATV.
Section 0 of every ATV contains guidance for preparing the specification. That guidance does not become part of the contract. It addresses whoever is tendering, not the contracting parties.
Observing it is nonetheless a precondition for a proper specification within the meaning of the VOB/A. Ignoring it creates gaps that return later as variations.
In practice: section 0 is the checklist when preparing the bill of quantities; sections 1 to 5 are the contract content. The article on building a bill of quantities covers the application.
Why the VOB/C matters for cost work
Three reasons make it the most important part of the VOB for anyone pricing work. They operate independently and all act directly on the price.
| Reason | Effect |
|---|---|
| It determines the scope of the item | what counts as an incidental service must be priced even where the text omits it; anyone unaware of section 4 prices too high or overlooks included work |
| It determines the quantity | two calculations of the same element diverge where the deduction rules are applied differently |
| It applies without express agreement | once the VOB/B is incorporated; unlike the VOB/A, which binds only public clients, it operates in every contract that incorporates it |
The relationship to the other parts of the VOB
The three parts of the VOB operate at different times and towards different parties. The VOB/C is the only part acting directly on the quantity.
| Part | Operates | Towards |
|---|---|---|
| VOB/A | before contract, within the procurement procedure | public clients |
| VOB/B | within the contract, from award | any party incorporating it |
| VOB/C | within the contract, technically and on measurement | any party incorporating it |
The second column contains the point distinguishing the VOB/C from the VOB/A. The VOB/A binds only public clients, because it is procurement law. The VOB/B and VOB/C, by contrast, operate in every contract incorporating them, including between private parties.
In practice a private client need not observe the tendering rules of the VOB/A but does apply the measurement rules of the VOB/C once the VOB forms part of the contract. Incorporation is covered in the article on agreeing the VOB/B.
The opening for digital measurement
With the 2019 edition, DIN 18299 was opened to model-based methods in a first step. A general enabling clause was introduced in sections 0 and 5, permitting digital measurement methods.
This is the interface with model-based quantity take-off: where a building model is used, quantities can be derived from it provided the measurement method has been agreed. The limits of that method are covered in the article on BIM-based cost determination.
Note that the enabling clause presupposes agreement. Without it the rules of section 5 apply unchanged, and a quantity derived from a model may diverge from the one contractually owed.
Related articles
This article reflects the position of the standards at the date of checking and serves professional orientation. It does not constitute legal advice and does not replace assessment of the individual case.