Build a Nachtrag on evidence, not argument

On the day the ground turns out different, the revised drawing lands or the client orders something extra, write it into the site diary: what was found and where, which crews and plant were standing there, the weather, and the instruction or drawing revision behind it.

Waarom: A diary entry is dated by the day it was written, not by the day the argument starts. That is the whole difference between a Nachtrag the other side reads and one they take apart line by line.

Upload the photographs the same day: the open trench, the layer that was not in the soil report, the obstruction nobody drew. The gallery reads the capture date and GPS position off each file, so every shot carries its own date and place without you typing one.

Waarom: Once the excavation is backfilled nobody can photograph it again. A dated, located photograph is the cheapest evidence on the project and the one thing that settles whether the ground really was different.

Raise the notice in the variations register as soon as the change is spotted: name the changed or additional work under paragraph 2 VOB/B, name the recipient, and set the date you expect an answer by. The notice goes in before the work is carried out.

Waarom: Announcing first and building second is what keeps the entitlement alive. A Nachtrag announced after the work is finished invites the reply that nobody ordered it, however good the site records are.

Where the work runs as Stundenlohnarbeiten, book the labour and plant hours against the change and flag the lines as daywork rather than measured work, then get the Stundenlohnzettel countersigned by the site supervision inside the period the contract allows.

Waarom: Daywork is recovered against the Nachtrag and measured work against the bill; mix them and you lose both. An unsigned Stundenlohnzettel handed over weeks late is the easiest item on any Nachtrag to strike out.

Derive the new position from the nearest position in the contract bill rather than inventing a fresh price, carry the same cost elements the original calculation was built on, and measure the omitted work as carefully as the added.

Waarom: A Nachtrag built on the original calculation can be checked in an afternoon. One built on a market rate that has nothing to do with the contract turns the whole negotiation into a fight about the price basis instead of the work.

Turn the announced change into a priced request with its cost and time impact set out, submit it against the notice it answers, and follow it through review to an agreed order that carries the figure into the contract final account.

Waarom: Priced but never formally submitted is work done for free. Tracking every open Nachtrag from angemeldet to beauftragt in one register is what stops a folder of changes agreed in principle reaching the final account unbooked.

Before the Nachtrag is contested, read its provability score: whether the notice went out in time, whether the other side acknowledged it, whether it ties to a governing instruction and a dated contemporaneous record. Work the weakest gap first, then assemble the evidence thread into one exportable pack.

Waarom: This is the step that decides whether a Nachtrag is paid or talked down. Finding the missing acknowledgement while the site is still open costs one email; finding it at the final account costs the whole item.