A District committee denied a request Thursday to allow a treehouse on Capitol Hill to jut about 20 inches into a narrow public alley — a win for opponents in the neighborhood who want it removed.

But the couple who built it vowed to keep the treehouse for their young daughters, saying they plan to move it a few inches to comply with city requirements.

The eight-foot-high treehouse has divided neighbors, some of whom oppose the treehouse hanging over a public space. The roughly 30-square-foot structure, designed to look like a castle, is perched in a 100-year-old elm tree on a U-shaped alley called Archibald Walk in Southeast Washington.

On one side are parents and friends who helped build it and say they have enjoyed children’s birthday and tea parties in the treehouse. Opponents say that the treehouse may seem charming to some but that there are concerns about code violations, a lack of public input before it was built and construction without the proper permits.

This Capitol Hill treehouse has sparked debate among neighbors, with some saying it shouldn't have been constructed over public property. (Larry Janezich/ Capitol Hill Corner )

After an hour-long hearing, the city’s public space committee voted 4 to 0 Thursday, with one abstention, not to allow the 20-inch encroachment over the public alley. Over its decades of existence, the committee has heard cases on a range of issues, from fallout shelters in the 1960s to sheds and playground equipment.

Three neighbors and a neighborhood advisory commissioner testified against the treehouse. But even after the vote, treehouse owners Ellen Psychas and husband Bing Yee said they are not deterred.

“The neighbors have not won,” Psychas said. “The treehouse will remain until the children grow up and they’re tired of it.”

Psychas, who counsels high school students about college, and Yee, a Department of Homeland Security lawyer, built the structure because they wanted a princess-like treehouse for their daughters, ages 3 and 5.

They said they checked with city transportation officials and the District’s Department of Consumer and Regulatory Affairs and found there were no specific regulations regarding the building — and permitting — of small treehouses like theirs.

The couple said they passed out fliers alerting neighbors that they were building it and got no response. They also hired an arborist to help them avoid harming the tree, then bought $300 worth of “eco-friendly tree-building hardware.”

Opponents also have said they are irked that the treehouse owners, in their opinion, took control of a small public space and essentially extended their private treehouse into it without approval.

At one point, one of the opponents filed Freedom of Information Act requests with city agencies to learn more about the permitting process of the treehouse, and the issue has been discussed twice by the area’s Neighborhood Advisory Commission.

The city issued a balcony permit in November after an inspector looked at the property several months after it was built.

This month, city officials said the couple should have obtained permits, adding that a review should have been completed before the treehouse was built.

Committee members said Thursday that they would work with the owners of the treehouse on the next steps to resolve the issue.

Psychas and Yee said they hoped to delay changes to the treehouse’s location until warmer months to avoid damage to the tree.

Psychas said they’ve been “touched” by how many people have offered to help move it 20 inches, which could put an end to a months-long dispute in the neighborhood.

“Perspective is key,” she said. “It’s a treehouse, not a crisis.”