You want to buy an existing building and convert it for a different purpose. In the document package an old notice about a military protection area appears. The seller believes the facility nearby is hardly visible any more and that the restriction is therefore probably no longer relevant. That assumption is not a sufficient basis for the planned intervention in the plot or building.
The spatial extent follows from the order
§2 SchBerG provides for the declaration of a protection area by order. This must include a plan of the extent; the statute also governs notification, later review and rescission. [ANORDNUNG]
Our editorial recommendation: Start with the specifically designated order and its current validity. Clarify with the competent authority which documents are decisive for your particular plot. A general radius around a visible barracks building or a private sketch map does not replace the decisive extent.
An old notice is neither a free pass today nor a certain bar
Keep the date, file number and the entire content of the notice on record. Ask for clarification whether it still reflects the current status and which subsequent decisions belong to it. That the order is old does not in itself mean it has been rescinded. Conversely, you should not infer a claimed current unusability of the plot from an unassigned document.
§2 contains a regular official review and provisions on rescission. This does not imply an independently calculated automatic expiry time for your order. [ANORDNUNG] What is required is the actual current status, not an assumption derived from age.
Describe the concrete intervention rather than merely the purchase intention
§3 SchBerG names, among other things, erection, alteration and removal of structural or other installations above or below ground level as well as certain changes to ground formation and land use. For the enumerated projects the provision requires a permit; it also governs the limits of refusal and possible exemptions. [GENEHMIGUNG]
Therefore formulate what you actually intend to change after acquisition. A conversation about the unchanged existing condition does not automatically answer the question of a later extension, a removal or a different land use. Which action is covered in your case and which procedure applies must be clarified professionally.
Hypothetical case: The purchase is based on an unchecked demolition plan
A buyer is interested in a building only because of the plot. She wants to remove it and build anew. The existing protection-area notice is initially set aside because the previous use continued for years. But information about her demolition and new-build plan is missing.
She now has the site situation, current order and her concrete project jointly assigned. The example does not say that the permit must be refused, nor that the previous use is unlawful. It shows why unchanged condition and planned intervention are different questions.
Link the purchase decision to the clarified status
Inform the contract advisor if your acquisition desire depends on a specific project. Record which information is available and which decision is still pending. Even a clarified protection area does not replace a review of other local building or usage requirements. What matters is a comprehensible status for exactly the change you intend to make by buying.