I consider that a rumor, unless you are jumping on an ongoing construction project (for example by the BT) ;)
Here too, I am sure exceptions have been signed that "can" extend the construction time.
Rhenish greetings
No, it is a complete new build (empty plot, but fully developed and registered in land registers, etc.) in solid house construction. No drywall, no wooden walls. Construction started last week, the ground floor is now almost completed. Next Monday the ground floor ceiling will be installed. Our neighbor, who also built with them, had the acceptance inspection the day before yesterday after 4.5 months of construction time (from the first time the excavator rolled in).
Weather conditions can delay the construction, but only the shell until the roof/windows are installed. And that will be done by mid-July. Currently, the sun is shining and it is warm, so delays are unlikely.
We chose the construction company because we want to finish quickly. The shorter the time, the lower the risk of total loss due to bankruptcy and so on. Also, the company is already larger and we trust that they know what they are doing.
We had a building notification prepared, which was confirmed on time with the payment request after 4 weeks.