Construction time calculation: 6 weeks planning time plus 7 months construction time

It is the same with us. We had a 4-week construction stop due to too cold weather. But that is not what I am concerned about.

Hmm, I can already see the lawyers...
Read through a few construction blogs. Then you might get a better feel for how things run on a construction site.
Just a well-meaning piece of advice...

It will take a bit more before I run to the lawyer...

So this construction period agreement is basically useless. If he now says 4 weeks of company vacation, another 4 weeks will go by...

Don’t drive yourself crazy about it. Usually, the weather is to blame when it takes 9 months. You can’t do anything about it anyway, even if from your point of view it shouldn’t be because of the weather. There will be other things that will occupy you more than such an agreement. Since I have been following here for some time, I assume a minimum of 12 months construction time for our solid house. It’s easier to live with if you don’t put so much pressure on yourself.

We had an exemption from the municipality, but the district office found something that needed to be changed on the plans. In your opinion, when would the time start then?

Of course, only after the district office is satisfied.

That's the same with us. We had a 4-week construction stop due to too cold weather.
But that's not what I'm concerned about.

Just google "Baustopp" once - a tip for the future construction project :)

Weather-related breaks are normal and a builder has to factor them in. Anything else is negligent. No matter how much you complain.
The builder is the last one to set deadlines ;)