On the day you moved into your home, you may have wondered how you'd ever fill all that space. Flash forward a few years and suddenly you're wracking your brain trying to carve out an extra storage area, or contemplating a major remodel to add more square footage.If this sounds like you and youre all out of ideas, theres a hidden resource lurking in your house: the hallways. Depending on how wide yours are (the minimum width, according to the International Residential Code, is 36 inches, but most residential hallways are 42-48 inches wide, and some homes even have 60- or 72-inch hallways!), you could be putting them to better use than as a mere conduit from one room to another.If your hallways are a cramped three feet wide, it will be difficult to make them pull double duty. But if your hallways are at least four feet wide, you have options to turn them into surprisingly useful rooms.Use a hallways as a dining roomIf you have a relatively wide hallway off the kitchen and you need a place to eat that isnt standing over the sink or balancing plates on your knees, you can turn that space into a quasi-dining room with a little creativity. With four feet of space to work with, a narrow dining table like this one, pushed up against one wall, can workat just under 16 inches wide, it leaves plenty of space for people to sit, and the chairs slide underneath when not in use. Hang some lighting over the table and install some shelving for storage and youve got yourself a small but usable dining room. If you're tighter on space, you could even consider a drop-leaf table that would fold flat against the wall when not in use.Set up a hallway libraryOne of the easiest ways to make a hallway function as a room is to turn it into a library or other shelf-focused storage area. Shallow bookcases like these (less than 10 inches deep) can make even a three foot hallway a viable library option. Adding narrow seating (like this entryway bench) against the wall between two of the bookcases, plus some wall-mounted lighting, can make that hallway feel like a cozy reading spot.Use a hallway as a conversation areaHallways are usually hurried through, but if you lack a space in your house to sit with a friend and chat, your hallway might offer an opportunity. If your hallway is at least four feet wide, a shallow bench with a back along with a narrow side table carves a spot to sit with a cup of tea and chat with a neighbor, or to hang out and think without the distraction of a TV mounted directly in front of you.A hallways can even be a "bedroom"No, your hallway will never be a real bedroom, even if its a ludicrous six feet wide. But if its at least four feet wide, it can be a place where surprise and overflow guests can sleep when needed. One or two narrow twin bed frames or daybeds can turn a wide hallway into a sleepover spot, and the daybed option doubles as seating for a conversation area or reading nook when not otherwise in use.