Ceilings are usually the forgotten fifth wall — kept white and bare, even if the rest of a room has been meticulously decorated.

But to professional designers, neglecting the ceiling amounts to leaving a space incomplete.

"I cannot finish a room without addressing what we will be doing to the ceiling," says Ashley Whiteside, an interior designer in Raleigh, N.C. "There is no, 'Yes, obviously we will leave it white.' Because this is an opportunity. It completely changes the entire juju of a room."

Interior print and fashion designer Dani Dazey says that "doing something with your ceiling actually makes the room feel bigger and more grand, and draws your eyes upward. It really can be such a statement."

Herewith, pros share some of their favorite ways to give the long-ignored fifth wall the love it deserves.

Paint the ceiling the same color as the walls

Despite what the paint jobs in most rooms would lead you to believe, there is no law that says you have to stop painting when you reach the ceiling.

"When the walls and the ceiling are the same color, you're just surrounded by this luscious color," says Liz Johnson, owner of Liz Johnson Design Studio and president of Design Collective DC. "It makes a space more cozy, like a warm hug — you feel enveloped." She says this is particularly true in small rooms.

But this project isn't quite as simple as coating your ceiling in the exact same hue as your walls. If you want the entire space to appear the same, the trick is to have your ceiling paint mixed so that it's 10-20% lighter than the wall paint. Otherwise, your ceiling will always appear darker, since light doesn't hit it the same way.

"It's not a vertical plane," explains Charles Almonte, an architect and interior designer in Silver Spring, Md. "The horizontal plane gives a different intensity to the color. It's always going to be in shade, so to speak, because it's not going to get the same amount of daylight as a vertical surface."

Paint your ceiling a contrasting color or texture

It's a much "bolder statement," as Almonte puts it, to paint your ceiling an entirely different color than your walls.

Going dark, even black, says Johnson, "adds visual depth and actually makes the room appear larger and taller." But softer hues also have benefits. Kelley Proxmire, an interior decorator in Bethesda, Md., suggests sky blue or light peach. "I paint a lot of ceilings, particularly in bedrooms," she says. "When you're in bed, you're looking up."

Soft pink is particularly flattering: "It just makes everyone glow, similar to sitting in candlelight," Whiteside says.

For wallpapered rooms, a painted ceiling can bring the whole look together. "Pick a color that mimics the mood of the wallpaper," says Johnson, who suggests going with the dominant color in a multicolored pattern.

You can also use paint to add texture. In one recent project, Almonte applied a coat of paint to the ceiling, then pressed it with a broom before it dried. "It just gives a little bit of dimension to the space rather than just a flat feeling," he says. Plus, texture can help hide imperfections.

Nina Farmer, owner of Nina Farmer Interiors in Boston, says she often uses Moroccan plaster on ceilings. "There is a reflective quality, but not in the same way that you would get out of, like, a lacquer or high gloss," she says. "It creates a nice, tranquil, subdued feeling."

Wallpaper your ceiling

Adding a pattern to the ceiling gives "an unexpected wow factor when you walk into the room," says Johnson, who favors a wallpaper with a shimmer or texture that contrasts with the walls.

Proxmire has used the same wallpaper on all four walls and the ceiling — but if you go this route, you'll have to be careful about selecting a pattern. Some designs — such as abstract or geometric prints, or cloud motifs — are more forgiving than others. That way, if it's not possible to exactly match up the pattern where the walls and ceiling meet, no one will ever notice.

Joanne Rodríguez, principal at Joanne Rodríguez Interior Design in Washington, D.C., dodges that hurdle by using two different, complementary wallpapers. For example, she might use a large-scale floral print on the walls, and find a diamond or square pattern in the same color palette "that coordinates with it."

Keep in mind that how you orient a pattern matters. If you've got a striped wallpaper on a ceiling in a long room, for instance, you'd want the stripes to be perpendicular to the long wall "to balance out that elongated-ness of the room," Almonte says.

Install ceiling tiles or slatted wood

In an older house, ceiling tiles can enhance a vintage look. They're often made of tin, mica or copper, and come in a variety of colors. "It can be a budget buster, but it's gorgeous," says Rodríguez. Just make sure you use tiles specifically designed for the ceiling, because they're lightweight.

Installing wooden slats on the ceiling, Whiteside says, makes "such a statement and it lends well to a ton of styles," depending on the wood you select. Beadboard, for instance, gives a French country or shabby chic look. Lighter wood might skew organic-modern, while a darker stain creates an industrial vibe.

An experienced DIYer could pull off either of these projects with the right tools. But if you're unsure of your abilities, it's probably best to hire a professional.

Install molding or ceiling medallions

When applied correctly, molding and ceiling medallions can look like they've been part of a home since it was built.

"I love to have fun with the molding," Dazey says. "It's just such a fun way to add what seems like architectural significance when it's really just a piece of wood attached to the wall."

She describes the installation process as "very easy" as long as you have some basic woodworking skills. And the supplies can be procured from any big-box hardware store.

Simpler moldings with fewer layers will work better in a room with low ceilings, while you can go for something larger or more extravagant in a space with higher ceilings.

Dazey is also a big fan of the ceiling medallion — an architectural flourish that gets installed around light fixtures: "It can make a blank-box room look like it's charming and like it was built that way."

Putting one up "is an afternoon project," Whiteside says.

Wood versions require nails, but foam or plastic-composite medallions are lightweight enough that you can stick them to the ceiling with adhesive. Whatever material you use, you'll want to caulk around the edges "because it'll never look finished until you do," Whiteside says.