Old-building risks: asbestos, heating, energy class

1950s–70s stock: two-wire electrics (renewal €5–15K — never DIY), end-of-life Steigleitungen (classic Sonderumlage), Floor-Flex tiles may contain asbestos — harmless if undisturbed, never sand or drill; float new flooring over.

Heating: the July 2026 GModG repealed the 65%-renewables rule and boiler-swap mandates — a dying gas Etagenheizung may again be replaced like-for-like. CO₂ pricing remains the long-term cost risk.

Energy class: G/H justifies −6–9% on price and banks now price energy risk (~0.15pp markup). Use it as a negotiation lever, not a reason to walk (unless the WEG can't fund improvements).

DIY boundary: painting, floors, cosmetics = yours. Electrical, gas, water, structural, anything in Gemeinschaftseigentum = certified trades / WEG resolution.