BOSTON -- Workers climbed ladders, wielded brushes and replaced floor tiles. Four days before Opening Day, Fenway Park was a very busy place.

Crews were putting the finishing touches Thursday on Major League Baseball's oldest stadium, the Boston Red Sox's eighth straight offseason of improving the ballpark so it might last up to another 50 years.

The work on the 97-year-old park included repairing concrete and waterproofing the original lower seating area built in 1912, adding 191 seats and 100 standing room spaces atop the roof along the right-field foul line and repairing an adjacent building that houses club offices.

The changes aren't as obvious as those made in past years, such as the addition of seats behind the Green Monster in left field in 2003.

"This year they relate in part to the long-term survivability of Fenway Park," Red Sox president Larry Lucchino said before taking Boston mayor Thomas Menino and media members on a tour of the park. "We are told by our engineers and architects that we will be able to play baseball in Fenway Park for the next 40 to 50 years."

The Red Sox will be back Sunday for a workout before Monday's opener at home against the Tampa Bay Rays, the team that beat them in the American League Championship Series.

Plans for next offseason include waterproofing the rest of the lower deck, which was added in 1934.

"We keep telling everyone we're in the ninth inning of renovations," Lucchino said. "Maybe we've got another year or two, something like this, but we eventually can see we've got it all planned out and we can see the finish point."

Once that happens, the sun will still be shining and the rain will be falling on Fenway Park. There will be no dome.

"Oh my goodness, bite your tongue," Lucchino said. "We understand that there are weather issues, but that's part of Fenway Park, part of New England. We're not going to ruin the charm and beauty and history of Fenway Park by adding a dome to it."

The Red Sox will add to the longest regular season sellout streak in the Majors, 469 games, but the economic downturn has made tickets tougher to sell.

"We're working very hard to keep ticket sales at last year's levels," Lucchino said. "Remember, last year we came off a World Series championship. ... We are keeping pace, roughly, with last year."

As he spoke on the sidewalk outside the stadium, dozens of workers inside prepared it for another Opening Day.

"We come up with a set of tasks and we get them done just in the time allotted," Lucchino said. "It will be ready by Monday."