Q. As we move to new office headquarters, we have a couple of rooms where we are in doubt of the necessity for a mezuza, because of the small size of the rooms. My rough estimates: Call office: 98 sq ft, but these area is being reduced by counters and cabinets attached to the walls (totalling 48 sq ft) that further reduce the usable area to only 50 sq. ft. The other is a servery that is 45 sq. ft. including area occupied by counter or 33 sq. ft. not including area occupied by counter. Thanks

A. Shulchan Oruch (Y.D. 286,13) rules that a room with an area of less than four square amos is exempt from the mitzvah of mezuzah. There are different opinions as to the equivalent of an amo in our standard measurements. Rav Chaim Noeh’s opinion is 49-cm. Which would require a room of 1.92m x 1.92m (6′ 3.5″ x 6′ 3.5″) or 3.69sq.m. Chazon Ish estimation is; 2.32m x 2.32m (7′ 7.33″ x 7′ 7.33″) or 5.39 sq.m.

In regards to counters and cabinets attached to walls or floors, Poiskim differ in their opinions, if they reduce the required minimum area necessary for a mezuzah, as they are useful for the room and could be seen as part of it. (Kvias Mezuzah Kehalacha ch.2 – Kuntres Hamezuzah p.68, Birur Halacha 223).

Horav Shlomo Miller’s Shlit”a opinion is that if the room is less than 6′ by 6′, no Mezuzah is needed. More than that, if the area includes the attached counters and cabinets, he recommends that a Mezuzah should be placed without a brocho.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a