With its enrollment climbing, Leopold Elementary, the largest elementary school in the Madison School District, is about to undergo another round of changes to create additional classroom space.

District officials are studying five options, none of them expensive, to provide enough room for students in the coming two school years.

But that's a temporary fix.

The Madison School District this summer will explore a long-term solution to Leopold's space crunch — including potentially controversial moves to redraw school attendance boundaries or to build a school to handle the growing population, School Board President Arlene Silveira said.

Leopold's enrollment has risen 20 percent in the past five years as increasing numbers of families have moved into low-cost apartments near the school on Madison's South Side, as well as to new apartments and single-family homes in Fitchburg.

A project this summer will create an additional classroom, either by knocking down a wall between two small rooms or by otherwise shifting the use of space in the building. That decision will be made by Sue Abplanalp, an assistant superintendent overseeing elementary schools; Mary Hyde, who has served as Leopold's principal for eight years but is being reassigned to Lindbergh Elementary; and John Burkholder, Hyde's successor, who currently is Midvale Elementary principal.

District officials are using the state's open enrollment program to hold down Leopold's enrollment, approving the requests of 11 students to transfer from Leopold to other Madison schools and 17 students to transfer to other districts.

The moves to Madison schools were allowed after officials determined they wouldn't substantially boost expenses at those schools.

As a result of those decisions, Leopold's enrollment is expected to climb by just two students next school year to 720, and by 30 students the following year. Then there won't be room for more.

Enrollment in the school's attendance area is expected to rise to 794 by the 2012-13 school year.

"There are subdivisions south of the school that are growing," Abplanalp said.

"And over the years, we are convinced that the size of Leopold will not accommodate the growth in the subdivisions, for the number of students that are projected."

Leopold's gains are occurring as the district's enrollment totals are changing little.

Enrollment this year is 24,268. The figure is expected to rise to 25,120 by the 2012-13 school year.

Kurt Kiefer, the district's coordinator of research and planning, noted that while the district's enrollment totals are relatively flat, the pattern is uneven, with growth occurring on the district's southern edge in the Leopold area, and on the far east and far west sides as housing developments appear.

The district's previous efforts to expand Leopold have met with mixed results.

In 2005, voters rejected a referendum seeking $14.5 million for renovations of the old building and construction of a second school on the Leopold site.

The School Board then decided to press ahead with a scaled-down $2.76 million construction and remodeling project at Leopold, paying for it out of the operating budget until voters in 2006 approved refinancing of the project with additional property taxes.

In response to past problems with crowding, the building's size has been expanded through two expansion projects from 68,000 to 93,000 square feet, school attendance boundaries have been changed twice, and third graders were bused to other schools for two years.