Question: Does one say a beracha on affixing a mezuza on one’s office doorway?
Answer: The Gemara (Yuma 11b) writes that only buildings that are used for dwelling require a mezuza. Thus, the Shulchan Aruch (YD 286:11) writes that a shop entrance does not require a mezuza. Elsewhere, the Shulchan Aruch (YD 286:2) does, however, require that one affix a mezuza to a storage room. The poskim have suggested different answers to explain the difference.
The Taz (YD 286:10) explains that one is more likely to access the storage area at any time of day and night, however the shopkeeper will never go to his shop at night while the Pischei Teshuva (YD 286:10) writes that the Shulchan Aruch is referring to temporary shops which are set up for a market and thus don’t require a mezuza.
Accordingly, there is a machlokes as to whether an office owned by a Jew requires a mezuza. Nonetheless, the poskim write that the owner should affix one without a beracha (See Minchas Yitzchak 2:83).
The Shulchan Aruch (YD 286:1) writes that one needs to affix a mezuza to a building that one owns together with another, though the Rema writes that one only needs to affix one if all partners are Jewish.
The Aruch Hashulchan (YD 286:2) writes that the Rema’s reason was because of the potential danger that can ensue from suspicious neighbours (See Shach YD 286:2). As this is no longer such a concern, one should affix a mezuza to such a property.R’ Shamai Gross (Shevet Hakehasi 4:263) writes that if one is hiring an office, then one should affix a mezuza. If one is working in an office that belongs to a non-Jew, however, there would be no need to affix a mezuza.