What "Altbau" means
For English-speaking readers: Altbau is the German term for buildings constructed before 1948 — most often Gründerzeit (roughly 1870 to 1914) or Wilhelminian-era apartment houses. These buildings have high ceilings, stucco cornices, original oak or pitch-pine parquet, double-leaf wooden doors, and a structural logic that predates modern insulation, electrics and plumbing.
The Rhein-Main region — Wiesbaden, Frankfurt-Westend, Mainz — holds one of the densest concentrations of Altbau in Germany. Much of it is under Denkmalschutz, the federal heritage protection regime.
The actual challenge
Renovating an Altbau is not a styling exercise. It is the negotiation between four forces:
- The historic substance. Stucco, parquet, doors, window proportions, original room sequences. These are the elements that make the building what it is, and most of them are protected by law.
- Modern living. Open kitchens, master bathrooms, walk-in wardrobes, underfloor heating, integrated lighting. Almost none of this existed when the building was drawn.
- The Denkmalbehörde. The local heritage office has approval rights over almost any visible change — sometimes including interior surfaces. Their process takes months.
- Energy and structure. Insulation, window upgrades, statics, fire protection, building services. Each touches the historic fabric and each needs a specialist Fachplaner.
Most failed Altbau renovations fail because one of these four forces is ignored. Our job is to hold all four at the same time.
Our methodology
We treat the existing building as a text that already has a voice. Our intervention reads it carefully before adding anything — we document what is there, identify what must stay, what can change, what was added later and can be removed. Only then does the design work begin.
The result is rarely a pastiche of the historic style, and never a denial of it. Stucco stays. Modern joinery sits next to it without trying to imitate it. Bathrooms can be unapologetically contemporary because the building can carry the contrast. Where a client wants this material and color direction set out before construction, we can develop it first as a standalone Mood & Material Concept.
This is the English version of what we describe in German as "Dialog mit dem Bestand." It is the core of our Altbau practice.
The German legal and permit context
If the building is listed (denkmalgeschützt), almost any visible change requires permission from the Denkmalbehörde. Even non-listed Altbau requires a Bauantrag for structural changes, and the Bauordnung sets rules about fire protection, escape routes and energy performance that interact with historic substance in non-obvious ways.
Joshua Lux is registered as Innenarchitekt with the Architektenkammer Hessen and the bdia — meaning we are entitled to file Bauanträge and act as your representative against authorities. We bring in specialist Fachplaner for structure, building physics, energy and fire protection as the project requires, and we coordinate them so you do not have to.
Selected references
VILLA A4 — listed building in Wiesbaden, 320 m² across four units, complete restoration from the structure outward. HAUS D7 — two adjacent Altbau buildings near Mainz, merged into a single 170 m² residence, awarded Best of Interior. THE COLLECTORS APARTMENT — 130 m² Altbau apartment in Wiesbaden, rebuilt around a private collection.
If you are looking at a non-historic apartment, see our apartment design page. For larger heritage houses rather than apartments, see our villa renovation page. For German-speaking clients, the deutschsprachige Residential-Seite covers the same scope.
Pricing
Our reference framework is the HOAI. In practice we work on a day-rate basis or with a fixed fee per service phase. Altbau projects almost always involve more LPH 1 and LPH 2 effort (analysis, permits, coordination) than equivalent new builds; this is reflected transparently in the proposal.
