It would be sacraligous as the building has not been properly blessed.
I would think its the same as when Mass was / is held in a hotel conference room or someone's living room, as with the early days of the SSPX I hear, and the traveling priests today. When I was growing up on a farm we were a mission Mass station of a larger parish about 20 miles away and had Sunday Mass at a public school cafeteria from about 1956 until 1964 when a church was built (built by the mission members, not a contractor) and a new parish erected. Military bases typically only have one or two chapels that all the various sects and denominations use on a schedule.
These things are governed by canon law and liturgical regulations and are best (and only appropriately IMH) addressed by priests have been trained in such matter while in seminary. That would be the best source to answer your question.
I recall a story from a Greek Orthodox priest who was an army chaplain at Ft. Lewis in Washington. After he celebrated the Divine Liturgy each Sunday there was a fundamentalist protestant service in the same chapel. The minister once commented to Father about the always lingering aroma of incense (which he undoubtedly didn't approve of). Father said to him: "In the next life there will be two smells, incense or brimstone. Take your pick."