On some days, after hours of banging, sawing and drilling at Tysons Corner Center, the hard-hat workers make their way to the Video Concepts store to clean up the dust that has settled on stereos and television sets. Once, the construction workers brought a vacuum cleaner.

"They mess it up, they clean it up," said Video Concepts assistant manager Pat Gulley, adding happily that the hard-hats also spend money in his store.

Like dozens of other merchants in this 19-year-old Northern Virginia mall, Gulley is willing to suffer the inconveniences of dust and noise because he thinks the center's $150 million renovation project will make his cash register sing.

"If we can put up with the dusting every single day, I can put up with the crowd increases," Gulley said. "Tysons will be the place to shop."

The Tysons Corner Center remodeling, dubbed the "Refining of a Classic," is at the halfway point. The project, which began last summer, will increase retail space by about 40 percent and parking spaces by 67 percent when it is completed in the fall of 1988, according to Geoffrey M. Donoghue, vice president of development for the Dallas-based Lehndorff Group, which is developing the mall.

The rejuvenated mall will include as many as 100 new specialty shops in a new lower level; the successful West Coast retailer Nordstrom, which is opening its first East Coast store here in March, and another department store, which will soon be announced, Donoghue said.

Addressing the number one complaint of shoppers during the construction phase -- parking -- three of the four new parking terraces will be open in time for the holiday shopping season. In all, the mall will have 9,000 parking spaces for holiday shopping, compared with 6,900 parking spaces at this time last year, Donoghue said.

He said the developers also have paid about $10 million for road and traffic improvements, including the widening of International Drive from four to six lanes and creating the four-lane road linking the mall to the bridge over Rte. 7. In addition, he said, the developers have contributed half the cost for a bridge over Rte. 123 that will connect the mall to the Tysons II development next door.

During the past year, the construction has meant confusion for shoppers and merchants. Once they managed to maneuver around the concrete barriers, the detour signs and the parking chaos outside the mall, they have been forced to contend with the barricades and the construction noises inside.

The work has not been easy. "It's just an incredible logistics and timing project to keep the mall running," said Charlotte Sykes, the public relations representative for the Lehndorff Group.

More than 600 plumbers, electricians, carpenters, mechanics and demolition crews are at work to make what mall developers hope will be the most talked-about mall on the East Coast. Their prime work shift is 10 p.m. to 6 a.m.

The workers are gutting the mall's basement, which has housed a storage and truck tunnel, to create the lower level for the new specialty stores. The mall floor will be cut through to make room for a two-story atrium.

When the renovations are over, the mall will have 25,000 square feet of skylit roofs to bring in more natural light, 150,000 square feet of Italian marble, which is being cut from mountains north of Milan, and 35 Washingtonia palm trees from Florida, which cost $5,000 apiece.

When the sprawling regional center opened in July 1968, it was the glittering centerpiece of a quiet bedroom community and one of the largest enclosed malls in the Washington area. But in this bustling commercial region, which a little more than two decades ago was a country crossroads, the mall's face lift is a sign of the times.

Directly across Rte. 123 from Tysons Corner Center, the long-awaited Tysons II shopping center is poised for a grand opening next fall and eventually will have a Saks Fifth Avenue, a Neiman-Marcus and an R.H. Macy & Co. store. Fair Oaks Mall, only six years old, is doing good business just nine miles away.

At Tysons Corner Center, "some of our customers thought it was like a comfortable old shoe," Donoghue said. "They would find everything they wanted in Tysons Center . . . . We wanted to bring it into the next century. It was 19 years old and showing it."

Mall officials were unwilling last week to release the names of the stores slated for the new lower level, explaining that 70 percent were committed but had yet to sign their leases. They said negotiations are under way for the rest. By next fall, these new tenants will bring the total number of specialty stores to 240, officials said.

Of the existing stores, three major department stores, Bloomingdale's, Hecht's and Woodward & Lothrop, have plans to renovate, and two smaller retail stores, Ann Taylor and The Limited, are expanding to two levels.

Donoghue said the mall's face lift was planned before competitive retail pressures became intense, but he acknowledged that "Tysons II accelerated our schedule."

The mall's general manager, Charles Cope, reports that the stores have maintained a high level of sales, with customers making more purchases when they come.

But a number of retailers interviewed recently complained that customers have shunned the mall during the construction and their business has been hurt significantly.

"It's been rather bad," said Janice Reuben, the manager of the Tall Girls Shop. "A lot of people don't want to come in because of the noise, the banging and the parking."

At Bakers, a women's shoe store, assistant manager Franklin Solomon said he would be "ecstatic" when he no longer has to wipe off construction dust from shoes and handbags on display. "Once everything is completed, it will be great for the mall, but right now we're taking a big loss."

In the view of Lee Rubner, who publishes the Tysons Corner Review, a newspaper for merchants in the area, "Anyone who says it's not hurting business is deluding themselves." But Rubner is optimistic: "People will come back to Tysons Corner and abandon other malls."

To Donoghue and the others sprucing up the mall, the outlook is only rosy. And Donoghue, for one, has good words to say about the notorious Tysons Corner traffic. "It's just a public perception that it's terrible. It's really not as bad as it seems."