The Large Room has ten wall nodes on which room expansions can be built: the short walls each have one, and the long walls four.
- Hatches can be built on the wall nodes. They pop out from the room a small distance when built.
- I Compartments, L Compartments, T Compartments, X Compartments, I Glass Compartments, and L Glass Compartments can also be built on the wall nodes.
- Multipurpose Rooms, Observatories, and Scanner Rooms can be built on the nodes, where they will create a tiny corridor leading to the room.
- Water Filtration Machines can be built along the same wall nodes, though note that they take up a small amount of floor space.
- Bioreactors, Nuclear Reactors, and Alien Containments can be built on nodes in the center of the room. The four nodes of this kind are marked by large black tiles.
- Partitions and Partition Doors can be built along the markings on the floor, as well as attached to walls at wall nodes. Note that Partition Doors must be built onto existing Partitions.
- Ladders can be placed where ceiling tiles are located, so long as another Large Room is above the tile.
- Large Rooms can be stacked perfectly. The roof of the bottom Large Room will be the floor of the top Large Room, and Alien Containments will stack like in Multipurpose Rooms. A ladder must be built to travel between the rooms.
- Alien Containments built in the Large Room will be approximately twice the size of one built in a Multipurpose Room.
- The flat roof of a Large Room can be used for placing Exterior Growbeds if the player does not wish to expand vertically.
The blueprint for this item can be acquired by scanning the Large Room at the Snowfox Base, or the second Large Room of Marguerit Maida's Base (the one without the glass roof). The Large Room of Research Base Omega cannot be scanned. It is crafted with the Habitat Builder.