At first glance, the boarded-up, weathered stone building on the makai side of Ala Moana boulevard looks more like a haunted house than a treasured national landmark.

Some of the Kaka'ako Pump Station's windows are shattered. Twisted and rusting metal tubing behind the main building makes for a less-than-inviting aesthetic. Then there's the "No Trespassing — Keep Out" sign on the locked property gate.

The disrepair makes it difficult to appreciate the building's celebrated Romanesque architecture, similar to that of the Bishop Museum.

But today the Hawai'i Community Development Authority takes a step toward transforming the pump station, which is listed in the National Register of Historic Places, into something accessible to the public.

A six-man Island Demo crew will demolish three structures attached to two of the original buildings that the development authority sees as detrimental to viewing the original architecture.

"We have an opportunity to take this treasure that's lain dormant for 50 years and turn it from an eyesore to an asset," said Daniel Dinell, Hawai'i Community Development Authority executive director. "(This weekend's work) is just to make it more presentable and to protect the historical nature of the site, and improve its aesthetics."

Dinell said there are plans for a small parking lot on the property, which would pave the way for future use of the structure, though the development authority has not yet decided what might go inside.

About 90 groups or individuals have expressed interest in using the facility, Dinell said, noting that some of the ideas include using the space for a restaurant, art gallery, museum, coffee shop or clinic.

"Kaka'ako is going through a renaissance, and this is a good symbol of how the old fits in with the new," he said, pointing by way of example to the University of Hawai'i's nearby medical school, which will be fully operational next month.

Jay Eisenzimmer, an estimator for Island Demo, said today's crew would go to work with sledgehammers. And he has no worries about the crew knocking over bits of the historic structure by accident. "We have a (method) called 'soft demo,' " he said with a laugh. "It's not just destroying everything you see — we use the appropriate touch."

Once the basic demolition of newer concrete structures "glued" onto the original is finished, volunteers from Painter's Warehouse will spend the next few Saturdays refurbishing the old structures. They'll take down the wooden boards and place clear plastic sheets over windows, apply a fresh coat of paint to several areas and plant palm trees in surrounding lots. Some initial cosmetic work, such as washing off graffiti and clearing the property of weeds, began last year.

In the absence of volunteer workers and supply donations, total refurbishment would cost about $100,000, Dinell estimated. Volunteers from Island Demo, the Hawai'i Architectural Foundation and the Historic Hawai'i Foundation are helping to lower the state's cost to $5,000.

"It's a good opportunity to do something productive for the community," Eisenzimmer said.

The station's three structures were designed by architect O.C. Traphagan and built in succession in 1900, 1925 and 1940. The station is considered Hawai'i's first professionally designed sewage disposal system, according to the development authority.

The primary building, facing Ala Moana, housed steam-powered pumps that carried sewage out to sea. The station was shut down in 1955.