Before you object, let me explain. Buildings, in and of themselves cannot be anything more than the items that they are made of - wood, brick, concrete, glass... It is our use of them that makes them what they are. Take any building out there, add the right lighting, hang art on its walls and call it a gallery, and it is. Take that same building, add dentist's chairs and equipment, call it a dentist's office, and it is. Almost.
The art gallery isn't really an art gallery without artists and the dentist's office isn't really a dentist's office without a dentist. Without people using the buildings as they are intended to be used, the buildings are just buildings with stuff inside. It is people using the buildings for their intended purpose that make the buildings what they are. A dentist could start seeing patients in the Gallery of The 567 today and it would be a dentist's office. Having an artist hang paintings on the wall of the dentist's office and opening the door for viewing transforms the dentist's office into a gallery. The building is just a building without people using it for its intended purpose.
Church buildings are, in that sense, just like art galleries and dentist's offices - it isn't the building that fulfills the church's purpose (mission), it is the people. Buildings can be built in locations that are a strategic part of the church's mission. They can be designed for the mission and equipped with items necessary for the mission. But without people, carrying out the mission, they cannot, on their own fulfill the mission. Buildings are, at best, only tools for the mission.
Your church is only as missional as you are. Your church will only reach people when its people reach people. Your church can only have influence in its location when the people of the church are active and involved as Christians in that location... a city within the city, a counter-culture to and within a culture.
More specifically, our church, New City Church can only see our city transformed, can only see our families transformed and friends transformed when we engage the people around us with the beautiful news of who Jesus is and what He has done for us. A building can't do that.