Telehaus, Former telegraph office in Mainz, Germany

The Telehaus at Münsterplatz 2–6 is a reinforced-concrete skeleton building erected 1928–1930 to designs by H. F. W. Kramer and Gottlob Schaupp, with Stadtbaurat Fritz Luft overseeing. Its angled, stepped mass rises six and a half and four storeys, with a pale render façade, dark-painted window crosses and shell-limestone and clinker cladding at street level. Broad niches beneath a stylised imperial eagle once carried the inscription TELEGRAPHENAMT.

Mainz had an optical telegraph line to Metz in 1813–1814, and an Austrian telegraph station followed in 1849, closed again in 1853. The city telephone network started on 15 October 1883 with 30 subscribers. After a 1926 competition, the telegraph office was built 1928–1930 to designs by H. F. W. Kramer and Gottlob Schaupp, opening on 7 February 1931 with 2,000 connections. A 27 February 1945 air raid gutted it; full restoration ended in 1950.

Locals call the former telegraph office "Telehaus". The name survives from its use as a telegraph and telephone exchange, opened in 1930 with capacity for 2,000 subscriber lines and formally inaugurated on 7 February 1931. Today Deutsche Telekom still occupies the building, alongside a Telekom shop and Ver.di offices.

The Telehaus stands at Münsterplatz 2–6, on the square's south side where Schillerstraße meets it, opposite the baroque Erthaler Hof. The entrance front faces the square; the building is in use by Deutsche Telekom, ver.di and a Telekom shop, so visitors see the exterior and the shop rather than the offices.

The building's foundation had to be a 5 to 7 metre deep pile foundation in reinforced concrete, insulated with acid-resistant clinker, because the ground was filled, partly marshy terrain with acidic groundwater over a dried-up side arm of the Rhine. The light render façade with dark-painted window crosses carries no architectural ornament apart from some shell limestone and clinker cladding on the ground floor.