Construction expert - how does he calculate the repair costs

Dear forum members,

I am planning to buy a house built in 2002. Since I have no knowledge of construction myself, I have asked a publicly appointed and sworn building expert to check the house for possible damages and give me rough estimates of the effort required to repair them. I explicitly do not want a court-admissible report, but rather a personal basis for decision-making regarding the purchase of the house.

Now my question is: after the on-site inspection, what exactly does the expert do to arrive at his assessment, especially regarding the costs? Does he have everything in his head and then write down his assessment? Or is there specific software or books that he uses and consults to find out what the repair of a damage costs?

Thank you in advance for expert answers

Best regards

As a rule, the expert makes notes, drawings with dimensions, and photos so as not to forget anything later. It's simply old school.

Thank you. This part is clear to me. What is unclear to me is which means he then uses to arrive at his assessment (see my exact question). Maybe someone knows background information or is an expert themselves.

Best regards

There are reference approaches that are used, just like with the real estate agent. This does not necessarily have to be software. These approaches are adjusted with markups and markdowns as well as regional peculiarities. Experience is then added, and the appraisal is complete.

Experience and hopefully somewhat up-to-date knowledge about the galloping construction prices.

Thank you for the quick responses. My expert charged me about 25 hours for the preparation of the report. ADDED to that is time for preparation and the on-site appointment. I received a table with the damages and the derived measures including the approximate costs. If you calculate the effort per line (one line = one damage including measures and costs) of the table, it comes to 45 minutes. That seems way too high to me!