Searchable building files: inspection dates and contracts

Anyone who operates buildings or installations often needs to know quickly: which contract covers this installation, when was the last inspection, where is the as-built plan? A knowledge base for the building file answers such questions with a source reference and can prepare a deadline list. It replaces neither deadline management nor inspection by specialists. Tenant data does not belong in it unless your data protection officer has decided otherwise.

What a building file contains

Depending on the property, a building file (Objektakte) holds maintenance contracts, inspection reports, as-built records with existing drawings, expert reports, permits and correspondence with authorities and firms. Much of it exists as a scan or as a PDF from an email. How far text recognition goes with poor scans is covered in the article Old plans and poor scans.

The typical questions are simple in practice, but the answer is scattered across folders: when was the lift last inspected? Which firm services the ventilation, and until when does the contract run? The example is invented, the kind of question is not.

What does not belong in it

Tenancy agreements, tenant lists, correspondence with tenants and access records for individual flats contain personal data. Some inspection reports also name tenants or flats, for example where an inspection required access to flats. The name of the inspector, by contrast, belongs to the documentation that section 17 requires. In Article 5 the GDPR requires that personal data be adequate and limited to what is necessary for the purpose (data minimisation) and kept in identifiable form only as long as the purpose requires (storage limitation). Whether and how you include such documents in a search is for your data protection officer to clarify.

By default they stay out. In practice that means building a building file only from installation and building documents, excluding tenant folders, and redacting or likewise excluding documents that contain tenant names or flat details until the question is settled.

The documents are processed only on a platform that can be operated in line with the GDPR, not in a consumer chat service. That also applies to expert reports and correspondence in which firms and contact persons are named.

Operator duties, in general terms only

Which duties apply to your property depends on installations, use and contract. The regulations below only show by way of example what deadlines and records mean. Your specialist planner, an inspection expert or your legal adviser clarifies the individual case.

For owners and managers of existing buildings, the Drinking Water Ordinance (Trinkwasserverordnung, TrinkwV) is the clearest example (as of November 2026). Under section 31, the operator of a building water supply installation must test the water for Legionella if it supplies the water as part of a commercial or public activity and three conditions coincide. First, there is a large water heater (capacity over 400 litres) or more than 3 litres of content in a pipe between the heater and the tap. Second, there are showers or other equipment that produces water mist. Third, the installation is not in a single-family or two-family house. Under section 2, the operator is a business or other holder of the installation, and a commercial activity includes supplying drinking water as part of a letting. Testing is due at least every three years for commercial but not public supply, and otherwise at least once a year. Under certain conditions the public health office can set intervals of up to three years. For a newly commissioned installation, the first test falls due within three to twelve months after commissioning. Whether this applies to your building is an individual question.

The Ordinance on Industrial Safety and Health (Betriebssicherheitsverordnung, BetrSichV) is an occupational safety regulation (section 1(1)) and is addressed to employers. Anyone who, without being an employer, uses an installation requiring supervision for commercial or economic purposes is treated as an employer under section 2(3). As an example for owners and managers of existing buildings it therefore works mainly for installations such as lifts. Under Annex 2, Part 2, an approved inspection body inspects lifts at recurring intervals, the interval may not exceed two years, and an interim inspection follows in the middle of the period. The employer sets the intervals under section 3(6) and records them in the documentation under section 3(8) no. 4. Due dates are given by month and year, and a recurring inspection counts as on time if it takes place no later than two months after the due date (section 16(3) in conjunction with section 14(5)).

For the record, section 17 names at least the identification of the installation, the date, type and scope of the inspection, the result, the deadlines for the next recurring inspections, and the name and signature of the inspector or, for documents transmitted only electronically, the electronic signature. Records and inspection certificates are to be kept at the place of operation for the whole period of use and presented to the authority on request, and electronic storage is permitted. For other work equipment, section 14(7) provides that the employer has the inspection results recorded and kept at least until the next inspection.

For the knowledge base, only one thing follows: the details these provisions name appear in your reports, and they can be found if the documents are readable and unambiguously named.

What the knowledge base does

It finds the passage. Asked about the last inspection of an installation, it shows the report with page and date, ideally with the inspector and the next deadline stated there. The answer carries a source reference that you check against the original, as described in the article Why AI answers need a source reference.

A deadline list can be prepared from this. One line per installation: installation, type of inspection, last inspection date, stated deadline, source reference. The language model reads the documents and makes the entries. A fixed program calculates the deadline date from the inspection date and the interval. A specialist sets the calculation rule for each installation, because it depends on the regulation. Under section 14(5) BetrSichV the period generally starts on the due date of the last inspection, or, if the inspection took place earlier, in the month and year it was carried out, with exceptions for periods over two years. If the interval appears in no document, the list reports a gap instead of guessing a deadline. Figures that the program has not confirmed carry the note “unchecked”.

Typical findings that become visible this way:

• A maintenance contract is about to expire, and a notice period appears in the text.
• A report names defects for which no acceptance or re-inspection is on file.
• There are two contracts for one installation with different terms.
• There is no report for an installation at all.

The knowledge base reminds nobody of deadlines. Your calendar or property management software remains responsible for that, and the list supplies the input.

How to begin

A pilot on one property is enough, planned as a starting assumption of four to six weeks. Collect ten questions that you have asked in recent months and note where the answer is found. Then measure how many of them the search finds. The precondition is a filing system with identical folders and unambiguous file names, as described in the article Project folder structure and file names. The technology behind it is explained in the article Making your project files searchable.

What the knowledge base does not replace

It replaces no deadline monitoring, no inspection by a competent person and no legal assessment. It does not say which inspections your property needs. It finds what is documented, and it cannot invent what is missing. It does not answer liability questions, which belong with your legal adviser.

What you can do now

1. For one property, list all installations subject to inspection and note where the latest report is filed.
2. Check whether reports exist as scans without a text layer by trying to highlight a sentence in them.
3. Decide which folders contain tenant data, and speak to your data protection officer before anything is included.
4. Build a template for the deadline list with the columns installation, type of inspection, last date, interval, source and query.