Anyone who has ever had to keep track of a months'-long email thread knows that most of the time a great deal of the headache could have been solved if someone just picked up the phone. Even more, conflicts get solved in an instant once two people on even a monstrous thread meet up to work through the problem. But every company still has those threads. Sometimes it's because nobody wants to own the project or make a final decision that they'll be held responsible for. But many times it's because there's no way to hold those small in-person conversations.
What can your company do to make interdepartmental problems easier to solve?
Have break rooms with lots of sitting room.
Most break rooms are tiny. They have a coffee machine, a refrigerator, and a microwave with no room to sit. That means your employees are either to leave the building during their lunch hour or go back to their cubicle. But having a lot of inviting seating means people from different departments will start to mingle.
Despite the negative connotation, cooler talk is good for business. If your employees can meet each other, have friendly, informal conversations, and start to make contacts in other departments, they are much more likely to reach out. It's also a lot easier to broach a contentious issue in the middle of a conversation than to walk over to their aisle.
Have small meeting rooms.
Sometimes the near silence of an open office prohibits conversation. Even if go over to a coworker's desk to hash out a logistical problem, knowing everyone is listening makes the speakers more defensive. It also keeps the conversation short because it's uncomfortable. Border your office space with unassigned offices and small meeting rooms so employees have somewhere to talk comfortably, show their screens on a large monitor, and spread out their notes.
Your office shouldn't just be built for individual productivity. Make sure you have the right set-up for collaboration by going to Studio Others here.