Q. We have an open staircase going down to the basement of our house. We were thinking of making the basement into a home office. How much of a door would have to be added to prevent any issues of Yihud (of the woman in the house) with the workers in the basement? Would a locked half-door (up to the banister) attached to the bottom of the staircase be enough, or would we have to add a wall with a complete door?
A. Horav Shlomo Miller’s Shlit’a opinion is that if the door is locked from the upstairs side and cannot be opened by one in the basement by extending his hand over to the other side and unlocking it, (since the key is put away), it would be permitted on the onset if the door is of normal height and in need if only ten tefachim high (about one meter).
The Rov added that there should be a separate entrance from the outside of the house to the basement, without going though the upstairs of the house. There should also be independent bathroom facilities in the basement.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a