You know what "curb appeal" is. It's that certain something that makes a potential home buyer linger at one house and not even ask to get out of the car at another.

It's the way the house sits on the lot, welcoming visitors, offering its face to the world, like a friendly smile.

It's the way the front door, the windows, the brick or siding and the roofline all seem to fit together. The way the vines clamber up the fence or twine around the light pole at the end of the sidewalk. The beds of roses, the clutch of day lilies, all carefully placed.

You know. It's often why some houses sell faster than others.

Of course, in this crazy market, some buyers will take anything with a curb. But how a house appeals to visitors from the outside still matters, says the National Association of Realtors' Iverson Moore. "What's inside is important . . . but if it doesn't look good, people won't stop outside and decide to go in."

And curb appeal isn't just for home sellers. A flashier exterior can make you feel better about living inside.

"Curb Appeal" is even the name of a popular show on Home & Garden Television. The challenge is to transform a tired or plain-Jane house into a showstopper. (The trouble, for Washington viewers, is that the houses are all in the San Francisco Bay area, close to the show's production company.)

Executive producer Mila Holt said the show looks for "really fun, transformative low-cost ideas . . . that have a big punch, like building an arbor in a certain way that gives the effect of adding a front porch but without the cost of adding a front porch. Or resurfacing a walk to look like stone."

The show came about, she said, because "people are hungry for these things."

So how else how can you get "it"? What if your house looks like every other house in the neighborhood? That happens on plenty of streets around the District and its close-in suburbs, where cookie-cutter developments popped up in the 1940s and 1950s, when speed of delivery and not design was key.

The Real Estate section offered its own challenge to local architects and designers. We found two houses in older neighborhoods where developers sold simple or plain designs and only a couple of models. Both houses have the original facades.

The challenge was to provide some modest makeover ideas for $5,000 to $7,500.

The budget was set low to fit the pocketbooks of those who aren't up to a pop-up, renovation or teardown. While the first idea was to limit spending to $2,500 to $5,000, most of the architects and design-build firms contacted said that number was unrealistic. Some who passed on the challenge said little can be done for under $10,000, or even $20,000, because landscaping materials and labor costs have jumped so high. Others passed because they were too busy.

But the six who volunteered said that if the homeowner does the work, a $5,000 to $7,500 budget would allow for enough changes to give a tired older home new pizazz.

The Center-Hall Colonial

This house in South Arlington was built about 1939, according to the longtime owner. He has never changed the facade. In this style of home, the entry door opens to the main floor, with steps leading upstairs to bedrooms. The living room is to one side of the entry and the dining room to the other. The neighborhood has many similar houses, most of which have porticos over the front door.

* Solution 1

An entry roof is the key to Dan Porter's redesign.

"The biggest problem this house has, although it does have a nice arched door and a round window above it, is that that's the only character the house has," said Porter, an architect with Case Design/Remodeling Inc. in Bethesda. "It needs a little more of a welcoming face."

The entry roof primarily provides a covering for bad weather, because Porter removes the ugly storm door, "but it also makes it feel a little more warm and welcoming."

Porter would have recommended a portico and columns, but the budget didn't allow it. He found a roof for about $2,000 at Walpole Woodworkers. A lamp post would run about $500 to $1,000, depending on how much underground wiring is required.

Porter also adds urns on the stoop, a new lighting fixture to the porch and flagstone steppingstones to the driveway. Because the driveway is in bad shape, he recommends replacing it at some point with two skinny lines of brick "tire tracks," and the rest grass.

Painting the shutters, windowsills and door green also helps warm the facade. "The white shutters are just too loud," he said. He leaves the other trim white, including the round window.

New shrubs would help, but Porter acknowledged that they can be costly. The owner, he said, could buy less-expensive young plants that would eventually fill out to his design or full-size plants that cost a lot more.

"If you could afford it, there's a lot more you could do," said Porter, including fixing the curbs and rebuilding the front stoop. If the roof needs replacing, for example, he suggested using a darker color.

Before moving ahead with the new entry roof, Porter recommended that the owner check local zoning regulations. "Some jurisdictions allow a roof to extend into the setback, some don't."

* Solution 2

David Shove-Brown, a professor at Catholic University and owner of Workshop, an architecture, design and consulting firm in the District, said a "big problem" is that the house has "a basic brick, like about 90 percent of the houses in that neighborhood, and there's nothing interesting about it."

His solution is to paint the brick tan and the downspouts and brick ornamentation under the roofline a darker shade. To give the house more depth -- "it's way too flat" -- he paints the window frames dark blue and the sills and brick headers a lighter blue.

He uses the same blue around the doorway and around the circular window.

"We used a new front door, with a larger opening" and removed the storm door, to make the entrance more appealing, he said.

Landscaping is another big issue. "It's spreading out too horizontally and the bushes are placed very haphazardly. It's not manicured now," he said.

Removing the yellow flowering bush and using coniferous bushes across the front would help. He puts a tall conifer on either side of the door "to give it some verticality."

Painting the house will cost about $3,000 to $4,000 and the landscaping will mean another $1,000 or so, the architect said.

While his redesign includes perking up the driveway, "that's just a recommendation," Shove-Brown said. "He could just seal what he has as a cheaper solution."

He said, "We came up with some basic design ideas because the budget is pretty limited. If the owner could spend the money, I would rebuild the front steps, redo the sidewalk and the driveway. But redoing the steps would cost five grand alone."

Shove-Brown would also soon replace the windows because they help make the house "look tired."

* Solution 3

The front door and stoop also drew most of Robert E. Beach's attention.

"This example of a Federal or 'Adam' style home incorporates some quality features that need to be both preserved and enhanced," wrote the Falls Church architect in an e-mail.

"The brick dentil frieze at the roof level is quite handsome, as is the circular window at the second level," he said, but there are some corrections that would immediately improve the facade.

The circular window, for instance, "tends to overpower" the door with its brick arch.

Adding "a typical period arrangement of columns, pitched entry roof and trim above the brick arch at the door . . . [will] give more mass and character" to the entrance.

The stoop is in need of repair, Beach added, and the "cheek" walls on either side of the steps don't match the style of architecture of the house.

He recommended repairing or enlarging the stoop and installing new steps that will accommodate a wrought-iron railing in a style typical of the period.

Beach noted that the builders seem to have "inverted" the two stone window heads on the first-floor windows. In other words, the piece of stone that is normally near the sill is on the top of the window. "I have compensated for this unusual look," Beach wrote, "by applying wood window heads with a crown molding above each. That additional material gives more weight to the first-floor windows so that they are more equal in impact to those at the upper level." The second-floor windows draw weight from the brick frieze that runs just under the roofline.

Beach estimated that his facade improvements would run about $4,700.

He also suggested planting a flowering tree on each side of the front walk and flowering shrubs near the foundation.

He would repave the driveway and clean stains on the facade from the paint on the shutters.

Beach said his 15-year-old firm does a lot of historic work, so he is familiar with the kinds of challenges he found in this house.

"All houses are slightly different but they have very similar problems. . . . Some of the houses of that period have elements that don't fall true to the period, or they have elements of several different styles of architecture," he said. A makeover offers an opportunity to help bring together the style.

"In other words, the house has a certain architectural vocabulary and I wanted to add new elements that are within that vocabulary."

The Split-Foyer

This 1958 house less than a mile from downtown Kensington is a split-foyer. That means the front door opens onto a landing with steps up to the main living area and steps down to the lower level. The house recently changed hands, and the new owners have been updating the interior, reseeding the lawn and removing overgrown shrubs. The house is in a neighborhood of similar houses, either split-foyers or split-levels. A particular challenge is that the lots are not wide, so the driveway sits under part of the window and factors into the curb appeal.

* Solution 1

The problem with this property is that it has been neglected over the years, architect Brian G. Thornton of Silver Spring wrote in an e-mail evaluation, "and further loses its identity because the model is repeated numerous times throughout the neighborhood.

"It's not a large house, but the split foyer at least gives it some height. The bay window feels like an aftermarket add-on and is incongruous with the modernist style. The mature landscaping needs to be updated."

Thornton, who has worked in the mid-Atlantic region since studying architecture at Hampton University two decades ago, said the problems include overgrown landscaping, an unattractive drive and walkway, an understated entry and minimal accessories and lighting.

His answers:

* Scale back the plants to show off the nice, original brick.

* Replace the bay window with larger glazed operating panels.

* Add simple window boxes and seasonal plants above the door and at the window sills.

* Add lanterns and a lamp post.

* Freshen and seal the drive and walkway.

* Use bundled timber to mark the walk.

To make the new entryway stand out, Thornton also suggested adding a textured glass door. He calculated that the work could be done for $5,000 to $7,500.

"This is a simple house, and it requires simple gestures to maintain a level of authenticity," Thornton wrote. "The improvements should feel natural and be thoughtfully applied."

* Solution 2

Meghan Walsh of Meghan Walsh Architecture in the District would also immediately get rid of the shrubbery around the edges of the house.

"The goal here," wrote Walsh in an e-mail that accompanied her sketch, "is to give the house a simple, clean, slightly modern look by clearing the landscape a bit and introducing some color."

The colors she picked are quite bold. She would spend $1,000 to paint most of the exterior a dark color, such as Benjamin Moore's Black Raspberry or Kendall Charcoal.

For contrast, Walsh would paint the siding under the roofline and the trim a beige color called Coastal Fog. She replaces the solid block of siding under the windows with three panels of exterior plywood painted a green called Rosemary Sprig.

If the windows are wood, Walsh recommends painting them beige, too. If they're vinyl, she wrote, "know first that vinyl is a non-environmentally friendly material. It should be a goal to replace these at some point. Aluminum-clad windows are another low-maintenance option, but [are] generally more expensive. They come with painted enamel finishes already applied. Choose the beige or black option for this palette of colors."

The door would be either a solid-core birch that is urethaned or a single-pane French door in a urethaned wood frame, she said in an interview. For privacy, Walsh would apply frosted sticky tape to the glass panel next to the door.

To add interest to the entry, Walsh expands the landing, using flagstone pavers. The side edge of the landing would be painted charcoal gray.

A welded-steel or iron canopy painted black or gunmetal gray goes over the new front door. It would cost about $1,000, she estimated. She advised the owner to get detailed architectural drawings for such an improvement.

Walsh replaces the blacktop with gravel and adds low walls of concrete blocks, two layers high, capped with flagstone. The blocks would be parged -- covered with a thin coat of mortar or plaster -- and painted charcoal gray.

Plant the front lawn "with something low, but not grass," she said. If the owners aren't gardeners, they could "try sweet potato vine -- it grows quickly and requires little maintenance."

Walsh estimated that the driveway treatment plus the plantings and new trees on the side of the house would run about $3,000 in materials.

* Solution 3

Mario Pareja of Ziad Demian, Mario Pareja, Suleiman Umar Architects in Alexandria said he "found this house to be very interesting" because it was typical of the late-1950s construction that rippled across the nation after Levittown, N.Y., changed how America built houses.

"A lot of the architecture being done when this house was built was moving away from post-World War II architecture and going more modern," Pareja said in an interview.

"What we found different in this house is that it is broken up into many different elements. You have the bay window, which is a nice feature, and an entryway with nice height, and then a second bay over the siding. But the house just does not come together."

To tie everything together, Pareja and his associates took "what we thought was the most interesting element -- the bay window -- and extended it and exaggerated it as a point of interest."

The design adds a curved canopy above the bay window that extends to a wooden pillar at the landing. The pillar is two feet wide by six inches deep by 12 feet high, reaching to just under the roofline. Over the doorway, the canopy connects to the house like a trellis, mirroring the bowed window.

Pareja removes the screen door and opts for an etched-glass French door. The vinyl canopy would run about $2,000 and the door $500.

Another $800 goes to paint. To give the house more interest, Pareja changes the siding running under the windows and the eaves to cement board with a stucco finish. A ribbon of light yellow runs across the fascia. The cement board and stucco would cost about $900 for materials and labor, he said.

Pareja also divides the driveway from the walkway with an annual garden. Stones link the top of the driveway to the front walk. And a landscape timber where the driveway ends adds more definition.

Next Saturday: Jazzing up the interior to speed up a home sale.

ORIGINAL This late-1930s center-hall Colonial in South Arlington has not had a face-lift for years. The curved brick over the doorway, the round window above the door and the brick dentil frieze at the roof level are its best features, but our three architects say the current design doesn't do them justice.SOLUTION 1 Add character through a new entry roof with a tasteful hanging light. Urn planters on the stoop, new shrubs and a lamp post enhance the charm. Because the white shutters are too loud, paint the wood trim and front door green.SOLUTION 2 To distinguish the house from neighbors, paint it light tan, with a darker shade on the chimney, downspouts and dentil work. Add depth by painting the windows a dark blue and the curved bricks a lighter blue. Tall conifers break up the horizontal look.SOLUTION 3 Emphasize the great features such as the dentil work and the round window. Focus attention on the entry by adding a typical period arrangement of columns, pitched entry roof and trim. Get rid of the brick columns of the stoop and add a wrought-iron rail.Inside, three suggestions for making over a late-1950s split-foyer.ORIGINAL This late-1950s split-foyer in Kensington recently changed hands. The new owners have been updating the interior, reseeding the lawn and removing overgrown shrubs. A particular challenge is that the lots are narrow, so the driveway sits under part of the window and factors into curb appeal.SOLUTION 1 This is a "simple house, and it requires simple gestures" to remain authentic. Cut back the plants, replace the bay with larger windows that open, add simple window boxes and plants above the door and at the window sills and add planters and a lamp post.SOLUTION 3 Unite the house by emphasizing its most interesting element, the bay window. Add a curved canopy above the bay that extends to a wooden pillar at the landing. Eliminate the screen door. Add interest with a ribbon of light yellow paint under the eaves.SOLUTION 2 Give the house "a simple, clean, slightly modern look by clearing the landscape a bit and introducing some color." Unify the colors. Expand the landing, replace the door and add a canopy. Replace the blacktop with gravel and add low walls in the same color scheme as the house.