My wife ran a successful home-renovation company in Israel.
In Germany, paperwork stopped her.
I'm Sergey, tech lead at Bergstone in Berlin. I watched it happen, and decided to fix it.
In short
Builders from abroad usually have the skills to grow in Germany. What stops them is German paperwork: contracts and letters full of paragraphs they can't read with confidence, and verbal agreements that nobody can prove later. BauWalker.OS is an AI assistant for German construction law (VOB/B, BGB) that explains documents in the crew's own language, checks contracts before signing and drafts German letters and invoices, always with a verifiable source.
The problem is not talent
Builders who come to Germany want what everyone wants: to grow. Bigger jobs, a crew, their own company. They have the skills. What stops them is a letter full of paragraphs they can't read with confidence.
The client asks for extra work on site. The builder says yes, does it, shakes hands. At the end the client refuses to pay: nothing was agreed in writing before the work started. A lawyer costs too much, so they give in.
It's not a lack of talent or ambition. It's a language barrier, and some clients know it.
Why the timing matters
About 25% of employees in the German main construction trade now hold a foreign passport (2025), up from 8% in 2009 (Hauptverband der Deutschen Bauindustrie). The law and the documents stay German. The explanation doesn't have to.
Germany has also set up a €500 billion special fund for infrastructure and climate neutrality, with a term of twelve years for approving funds (Federal Ministry of Finance). Roads, rail, bridges, buildings. Crews will do much of that work, and every fourth person will hold a foreign passport. The builders who can handle German paperwork will take the bigger jobs. The rest will watch.
What BauWalker.OS does
So we built BauWalker.OS:
- Explains German construction law (VOB/B, BGB) and shows the source for every answer
- Checks contracts before you sign and flags risky clauses
- Drafts the German letter or invoice. Nothing leaves without your click
- Speaks the crew's language: Türkçe, Polski, Русский, Українська, Română and more
How it works under the hood
An open-source model reads contracts and invoices on our own server. Every cited paragraph is verified against a law database. No verifiable source, no answer. A script calculates amounts, not a model.
It doesn't replace a lawyer. It helps you understand the situation faster and arrive prepared.
You can try it at app.bauwalker.de, or write to us at info@bergstone.de.
Frequently asked questions
What is BauWalker.OS?
BauWalker.OS is an AI assistant for German construction law. It explains VOB/B and BGB with the source for every answer, checks contracts before you sign and flags risky clauses, and drafts German letters and invoices that only leave with your click.
Why do builders from abroad struggle with German paperwork?
The skills are there, but the law and the documents stay German. A typical case is extra work agreed on site with a handshake: if nothing was agreed in writing before the work started, the client can refuse to pay at the end, and a lawyer is often too expensive to fight it.
How does BauWalker.OS make sure its answers are correct?
Every cited paragraph is verified against a law database. If there is no verifiable source, there is no answer. Amounts are calculated by a script, not by a language model.
Does BauWalker.OS replace a lawyer?
No. It helps you understand the situation faster and arrive prepared.
Which languages does BauWalker.OS speak?
It speaks the crew's language: Türkçe, Polski, Русский, Українська, Română and more.
Where are my contracts and invoices processed?
An open-source model reads contracts and invoices on Bergstone's own server.