Anthropologist Robin Dunbar of the University of Oxford, whose research on group size began in primate studies, describes human social networks as nested layers. One of those layers holds roughly fifteen people: the circle you can actually keep in your head, whose work you know without asking. Every architecture office that has argued about whether to hire one more person has met this number, whether it knew the name or not.

One Zürich practice put the number in writing. According to the jubilee text on its own website, BKG Architekten AG was founded in 1951 by the architect Peter J. Moser, “in einer Zeit des Aufbruchs”, in a time of new beginnings. In 1964 a villa in the Seefeld quarter, Münchsteig 10, became its headquarters. The office says that address stayed its fixed point of departure for more than 60 years. This September, according to BKG’s own news page, the office welcomed clients, business partners, friends and staff to two Opening Days at its new premises, Münchhaldenstrasse 21, CH-8008 Zürich, to mark 75 years.

The jubilee text also contains a sentence any practice principal will read twice. After a building-boom peak of around 40 architects, the office wrote that for a practice doing a large share of industrial building, the optimal size over the long term is probably “zwischen 15 und 20 Mitarbeitern”. That is a historical judgement from the office’s own past, not a statement of its headcount today. It is still a rare thing: an office naming its own right size.

A lineage of named people

The story the office tells is one of continuity. Creed Kuenzle joined around 1963 and Hans Gerber in 1970, the year the firm became an AG. Dr. Jürg Bühler followed later. The project chronicle on bkg.ch runs from the KABA production halls in Rümlang (topped out in 1967) and the MOTAG Automobilzentrum in Dielsdorf, the first BMW import centre (opened in 1969), to the 1968 “Zum Raben” competition on the Limmatquai, where, by the office’s count, 84 offices took on the same urban brief. Later came the Hammergut renovation in Cham (1985–1992), the Dolderbahn refurbishment in 2004 and the phased renovation of the Grasshopper Club Zürich tennis facilities from 2008 to 2021. Today the office is led by Patrick Manser, Christian Gerber and Nadine Gerber-Hunziker.

In 1978 Kuenzle wrote: “Wer als Architekt bestehen will, muss sehr diszipliniert arbeiten.” Whoever wants to last as an architect has to work with great discipline. PAZ’s concept panel on the Bauhaus basic course recalls Hannes Meyer of Basel holding that building is organisation, not composition. BKG’s 75 years read like a long, quiet proof of that idea.

←TODAY: A 75-year-old Zürich office opens a new house and still has a written view on its own right size. →3012: The practices still standing are the ones that knew their shape and wrote it down. Fulcrum: Changing address shows you what a culture carries with it and what the walls were holding for it.

The questions we are left with

We are fourteen people in a half-renovated Werkhalle on the Sihlquai, one short of BKG’s band, and we read that sentence as a question addressed to us. What size is right for an office whose work is Wettbewerb models one month and Ausführungsplanung the next? And what do 60 years at one address do to a culture? Do the habits live in the rooms, or in the people who move them? We do not know BKG’s answers, and their pages do not give the reasons for the move. The questions are worth asking anyway. The trade-off is plain: a small office keeps its knowledge in conversation rather than in documents, and that closeness is exactly what makes the knowledge fragile when people leave.

Atelier: If AI tools now let fourteen people produce what twenty used to, the size question moves from “how many hires” to “how much of our method is written down”. On Monday, draft a one-paragraph size statement for your office, the way BKG did: at which headcount you stop hiring and start documenting or scripting instead.

Hack: Pull your monthly heads-and-hours curve out of the timesheet database so the size debate starts from your own numbers rather than from a feeling. One query against your project-controlling table is enough:

SELECT date_trunc('month', day) AS month,
       count(DISTINCT person_id) AS heads,
       round(sum(hours) / count(DISTINCT person_id), 1) AS hours_per_head
FROM timesheet
GROUP BY 1 ORDER BY 1;

If hours per head keep climbing while the headcount stays flat, your office is already working above its natural size.

PAZ Takeaway: For a practice whose method lives in its people, PAZ can set up PAZ-GPT on the office’s own archive of project reports, BEP drafts and detail notes. Decades of decisions then become something the next colleague can query instead of rediscover.

Write your office’s right size down, and date it, so whoever reads it in 2101 knows what you meant.