Your Hamburg Rental Building Got Sold as Condos: The 10-Year Kündigungsschutzfrist, and Why Converting It Got Harder in 2021

The Official Rule

Learning that your building has been sold off in pieces as individually owned apartments is unsettling, but the sale by itself doesn’t put your tenancy at risk. What actually matters is a narrower moment: the point where your own specific unit changes hands to a new individual owner. In Hamburg, that moment sits underneath two separate layers of protection, one that decides how long you’re safe once it happens, and another that decides how easily the conversion could happen in the first place.

Once your unit is sold to a new owner after the building has been converted into condominiums, that owner cannot terminate your tenancy for Eigenbedarf or economic exploitation for 10 years, not the 3-year federal baseline. Section 577a BGB sets the nationwide floor at 3 years but lets state governments extend it to as much as 10 years, by ordinance, in areas with a genuinely tight rental market. Hamburg has used that authority at its maximum, citywide, in every one of its 7 districts, continuously since the protection was first extended in 2013 and 2014. The Senate renewed the current ordinance, the Kündigungsschutzfristverordnung, on August 8, 2023, alongside a separate renewal of the city’s rent-increase Kappungsgrenze on the very same day. It took effect September 1, 2023, and, because Section 577a Absatz 2 BGB allows a single ordinance to run for up to ten years, it’s in force through August 31, 2033.

It’s worth noticing something that trips people up if they’ve already read about Hamburg’s other two rent ordinances. The Kappungsgrenzenverordnung, enacted the same day as this one, only runs through August 31, 2028, five years shorter, because the BGB provision behind rent-increase caps limits that specific kind of ordinance to five-year cycles. Section 577a’s own limit is different: it lets a state fix the blocking period “for a duration of no more than ten years” in one go, so Hamburg’s Senate simply used the full window available to it. Two ordinances, signed on the same date, expiring five years apart, purely because the two underlying statutes cap them differently.

What actually decides whether your building gets converted in the first place is a separate matter, and this is where Hamburg has changed more recently than the ten-year number itself. Conversions inside Hamburg’s designated preservation zones had been climbing fast, from 85 in 2018 to 325 in 2019 to 715 in 2020, and in mid-July 2021 the Senate formally declared Hamburg a municipality with a particularly strained housing market. Since November 13, 2021, a citywide ordinance under Section 250 BauGB has required district approval before any existing rental building with more than 5 apartments can be split into individually sellable condominium units, anywhere in the city. Permission still has to be granted in a handful of situations: settling an inheritance among heirs, selling to family members who will live in the unit themselves, or selling to at least two-thirds of the building’s sitting tenants. Outside those, a district can simply refuse it.

A second, narrower layer closes the gap the citywide rule leaves for smaller buildings. Inside Hamburg’s Soziale Erhaltungsverordnung zones, social preservation areas designated under Section 172 BauGB, the same approval requirement reaches buildings with 5 units or fewer too, the size category the citywide rule doesn’t cover. As of the Senate’s most recent renewal on October 8, 2024, effective January 1, 2025 through December 31, 2029, 13 such zones spread across 5 of Hamburg’s 7 districts, protecting an estimated 235,000 residents.

Photo by Simeon Maryska on Pexels

Neither of these approval layers is the same thing as the 10-year termination block, and mixing them up is the mistake worth avoiding. The Section 250 and Section 172 rules govern whether, and how, a landlord is even allowed to convert and sell your building in the first place. The Kündigungsschutzfristverordnung only starts mattering afterward, once a conversion has actually happened and your specific unit has actually been sold. A building can clear the approval stage and still sit converted, unsold, for years, with nothing changing for you as a tenant in the meantime.

The clock on that 10-year block is precise about what actually starts it. It is not the date the building’s conversion into separate condominium units was completed, and it is not the date a purchase contract for your unit was signed. It’s the date the new individual owner is actually entered in the Grundbuch, Germany’s land register. A unit can sit converted and unsold for years, and nothing about your tenancy changes until an actual new owner is registered against your specific apartment.

What Real People Say

Hamburg’s tenant-advice organizations describe the practical sequence in three steps, and the order matters. First, check whether your address actually sits inside one of the 13 Soziale Erhaltungsverordnung zones using the city’s own Geoportal, since that tells you whether the smaller-building approval rule reaches your specific address at all. Second, if you’ve heard your building was converted, ask your district’s Bauamt or Bezirksamt whether, and under which exception, an Umwandlungsgenehmigung was actually granted, since a two-thirds tenant-sale approval works differently from a straightforward family-use approval. Third, and this is the step guides emphasize most, get the exact date the new owner was entered in the Grundbuch before assuming anything about your own timing, since that date, not the sale announcement or the contract signing, is what the entire ten-year calculation turns on.

The scale of the conversion surge that led to the 2021 citywide rule is itself part of the local conversation: approvals inside Hamburg’s preservation zones alone climbed from 85 in 2018 to 325 the following year to 715 in 2020, an eightfold jump in two years that tenant advocates pointed to directly when pushing the Senate toward its July 2021 declaration of a strained housing market. That history is also why Hamburg’s Senate has continued pressing, at the federal level, for tighter general rules around Eigenbedarf terminations beyond this specific ten-year window, arguing the broader termination framework still leaves room for abuse even where the conversion-specific protections are working as intended.

A recurring theme in tenant caseworkers’ own accounts is how often the ten-year clock gets challenged indirectly rather than head-on. A dispute that reached Germany’s Bundesgerichtshof in January 2026, arising from a Munich building but setting precedent that applies equally in Hamburg since Section 577a is federal law, involved a buyer who converted a building and then, within about a year, transferred one unit into a family partnership with his spouse and adult children, who then filed for a personal-use termination. The BGH (case VIII ZR 247/24) confirmed what lower courts had already found: the blocking period keeps running from the original registration date regardless of what ownership structure the owner later moves the unit into.

Step by Step

1. Check whether your building sits inside one of Hamburg’s 13 Soziale Erhaltungsverordnung zones, using the Geoportal’s Schutzgebietskarte, since that determines whether the smaller-building conversion-approval rule applies to your address.
2. If you’ve been told your building was converted, ask your district’s Bauamt whether an Umwandlungsgenehmigung was actually granted, and under which exception, since that shapes what commitments the owner may have made when converting.
3. If your specific unit is sold, get the exact date the new owner was entered in the Grundbuch, not the date of the sale contract or any earlier announcement, since that registration date is what starts the 10-year clock.
4. If a termination notice for Eigenbedarf or economic exploitation arrives, calculate whether 10 full years have passed since that registration date, since Hamburg’s citywide protection runs at its legal maximum through at least 2033.
5. Watch for ownership restructuring after a sale, like a unit being transferred into a family partnership shortly after purchase, since German courts have confirmed this doesn’t reset the clock or create an exemption.
6. Get a second opinion from Mieterverein zu Hamburg or a tenancy lawyer if a notice looks like it arrived before the protection period actually expired.

Compliance Note

This page explains the general framework around Section 577a BGB, Hamburg’s Kündigungsschutzfristverordnung, and the Section 172 and Section 250 BauGB conversion-permission rules as they apply in Hamburg in mid-2026. It is not legal advice, and whether a specific termination or conversion is valid depends on your building’s own permission history, your move-in date, and the exact Grundbuch registration date of any new owner. Confirm your own situation with Mieterverein zu Hamburg or a tenancy lawyer before assuming a particular notice is valid or invalid.