On 27 September 2026, voters in the City of Zürich wrote into zoning law what a tall building owes the people at its foot. SRF reports 65,852 votes to 39,432, about 62.5 %, for the city parliament’s version of the partial BZO revision for high-rises, the Teilrevision Hochhäuser. The rules ask four things of a tower. It must stand in a smaller set of zones, prioritised near rail lines and in Zürich North. From 40 m it must give its ground floor to public use. Every tower, whatever its height, must go through a design competition. Any bonus floor area must go to affordable housing and nothing else.

These are the first full rules for building tall in Switzerland’s largest city since 2001. Martina Wundling noted in espazium on 25 August 2026 that the existing high-rise zone area goes back to the 2002 supplementary plan. The city has been planning towers on a map drawn more than two decades ago.

Two city-authored drafts, one question

Voters chose between two versions of the same revision, and both were written inside the city. The Stadtrat and the Amt für Städtebau proposed three tiers of 40 m, 60 m and 80 m on the principle je höher das Hochhaus, desto strenger die Anforderungen. That meant public ground floors, outdoor space where people can stay, contributions to the local climate and limits on grey energy. The Gemeinderat tightened that framework. Writing in Tsüri on 1 September 2026, Dominik Fischer sets out what the adopted Vorlage A adds: tower zones cut to roughly half their current area, a public ground floor from 40 m, and a competition for every high-rise. SRF adds two more points: from 60 m, a Gestaltungsplan approved by the Gemeinderat, and bonus floor area reserved for affordable housing.

One fact frames the result: neither version adds building density. Maximum densities stay where they are. The ballot did not ask how much city Zürich gets. It asked what shape that city takes and who benefits. Baublatt (sda) puts the pressure in numbers: the city grew from about 408,000 residents in 2014 to 448,664 at the end of 2024, and 2,000–3,000 new apartments are built each year.

←TODAY: Zürich’s tower brief now opens with the ground floor, a competition and an affordable-housing price on extra floor area.
→3012: The towers that remain in use in Zürich 3012 are the ones whose base belonged to the street from the first sketch.
Fulcrum: Height is now traded for obligations, not for floor area.

Read it as a system

Read the new rules as a stack of height thresholds. Each one adds a new requirement:

• 30 m: Swiss fire-safety requirements for high-rises apply. This threshold is not new.
• 40 m: a public ground floor is mandatory. Buildings up to this height are limited to neighbourhood centres.
• 60 m: a Gestaltungsplan approved by parliament is required.
• Every tower: a competition, plus higher requirements for open space, greening, urban climate and resource efficiency (Baublatt).

Putting towers near rail ties height to transit capacity, so the station and the tall building become one planning question. There is a trade-off. Halving the zone area puts more weight on each remaining site, and a competition for every tower adds time and fees before the first floor plate is drawn. Clients should budget for that from day one.

Atelier: For a Zürich studio entering a tower competition, the first model is no longer the floor-plate stack. It is the plinth: its public programme, the outdoor space it gives back, its effect on the microclimate and the grey energy of the structure. The parametric logic that PAZ Building System Specialist Alina McConnochie built for HYPERMIX in Rhino and Grasshopper, with sliders for balcony depth, window ratio and materials, is the right kind of tool for this. Point its first sliders at the ground floor. Monday move: rebuild your office’s tower template in Grasshopper so that plinth depth, public frontage length and structural grey energy (kg CO2e/m²) are the first three inputs, ahead of storey count.

Hack: Measure how far each height threshold casts a shadow across the public space you now owe the street. At Zürich’s latitude (47.37° N), the noon sun at the winter solstice stands only about 19° above the horizon. That is the worst case for the forecourt your competition entry promises. Run this in GhPython or plain Python:

import math
lat, decl = 47.37, -23.44          # Zürich, winter solstice
alt = 90 - lat + decl              # noon sun altitude in degrees
for h in (30, 40, 60, 80):
    print(h, round(h / math.tan(math.radians(alt)), 1))

In December, a 40 m tower casts about 115 m of noon shadow and a 60 m tower about 172 m. Wire h to your height slider, and the forecourt responds to the sun from the first iteration.

From the late 2070s, I can tell you that the towers that aged well kept their ground floors open. A city can retrofit a facade, but it can rarely give back a street. A larger total revision of the BZO is already underway, so the brief will keep moving. Model the plinth first, put shadow and grey energy on the same screen as height, and bring that model to your next competition kick-off.

Sources & Further Reading

• Primary: SRF — Abstimmung Stadt Zürich: results and rules of Vorlage A
• Reinforcing: Tsüri (Dominik Fischer) — Das musst du zur Zürcher Hochhausabstimmung wissen
• PAZ context: HYPERMIX by Alina McConnochie