With presidents, prime ministers, and perhaps the paparazzi coming to town in September for the G-20 summit, the David L. Lawrence Convention Center is redding up.

And apparently not a moment too soon for one recent visitor who complained to authorities there about dirty windows and ledges at the $373 million center, which will host the event.

Over the next month or so, workers will be painting, washing windows, planting flowers, and maybe adding or upgrading signs in an effort to prepare for the Sept. 24-25 summit and two other big events coming up soon, the AFL-CIO constitutional convention and the Forest L. Wood Cup Championship, a bass fishing tournament.

The aim is to make the world's largest green convention center one of the cleanest.

Mark Leahy, the convention center general manager, said much of the work is standard maintenance that would have been done even if the summit were not being held in Pittsburgh.

But he noted that officials will "step it up a bit," knowing that world leaders will be using the center.

"When company comes, you do an extra scrubbing," he said.

"Any time there's a big event coming up, you try to time it so everything is in perfect shape. Of course, we're paying particular attention to [the summit], and we're pretty excited about it; and we think the building will be looking great," added Mary Conturo, executive director of the city-Allegheny County Sports & Exhibition Authority, which owns the building.

As part of the summer cleaning, the SEA board expects to vote tomorrow on a three-year contract worth about $54,000 to clean the center's windows.

Mr. Leahy and Ms. Conturo said the pact was routine for the building, whose floor-to-ceiling windows offer visitors picturesque views of the Allegheny River, its bridges and the city's sports stadiums.

But it may have taken on some added importance after the recent School Building Expo at the convention center.

Ms. Conturo acknowledged that she received a complaint from one local person who had attended the event about dirty windows, ledges that needed to be wiped and problems with the weather stripping.

She would not identify the person who made the complaint but said she had spoken to Mr. Leahy about the issues, and that they would be addressed immediately.

"We're always focused on the maintenance of the building.

These are things that are always of concern to us.

We're very proud of the building, and a well-maintained building is very important to us and important to the experience of visitors there," she said.

Officials affiliated with the School Building Expo itself had no issues with the center, said Lou Mancini, vice president of operations.

"We didn't have a problem. We were pleased," he said.

Mr. Leahy said there would be a 10-day window after July 4 during which there will be little activity in the building.

That will allow time to do the painting, window cleaning and other maintenance work.

They hope to have the window work done before the bass fishing tournament, during which "everybody's going to be looking out the windows at the river," Mr. Leahy said.

Just how much all the work will cost is anybody's guess.

No estimates were available.

Mr. Conturo said she also had received offers from local organizations that have volunteered to upgrade flower beds and planters outside of the convention center in time for the summit.

The SEA, she said, is "very receptive" to the offers.

"There's a lot of interest in this and there's a lot of people who want to do what they can to put our best foot forward here," she said.