The owner of Valley of the Temples Memorial Park will preserve and enlarge its historic main building, which includes Hawaiian heiau references, under a plan to establish mortuary services and a bigger chapel at the Windward Oahu property.

NorthStar Memorial Group announced the plan Monday after contemplating how to expand services over the past couple of years and addressing concerns that the architecturally significant building visible from Kahekili Highway in Kaneohe might be demolished.

“It was a good journey over the last couple of years to get to this design,” said Mark Gilmore, a regional vice president of Texas-based NorthStar. He said enlarging the building and maintaining its key architectural features honors and preserves history while meeting the needs of the company to serve families into the future.

The building, designed by noted Hawaii architect George “Pete” Wimberly and built in 1965, three years after the cemetery was established, is 5,751 square feet and used as administrative offices with rooms to help families make burial arrangements.

The expansion, which will include enclosing a central courtyard, will enlarge the building to 10,036 square feet and include a chapel with seating for more than 200 people plus a covered lanai. That is much more than can be accommodated at the park’s existing Trousdale Chapel, which is in a different part of the cemetery. Additionally, mortuary services will be offered in the enlarged main building, which is something that Valley of the Temples did not provide on site but did offer through Williams Funeral Services, also owned by NorthStar.

Elements in Wimberly’s design include a lava rock platform under the building and a towerlike portico designed to reflect elements of heiau, ancient Hawaiian places of worship.

The possibility of demolishing the landmark, which was contemplated by NorthStar, led the Historic Hawai‘i Foundation to list the building as one of its most endangered historic places in 2014.

Kiersten Faulkner, the nonprofit group’s executive director, commended Valley of the Temples for working to preserve the building. “This is an example of the outcomes that are possible when owners and community members engage in a spirit of collaborative problem solving,” she said in a statement. “The building is a landmark along Kahekili Highway and is historically significant for its design and as the work of a master.”

NorthStar worked with Historic Hawai‘i on a preservation plan, and Honolulu-based architectural firm Fung Associates Inc. led the design and renovation work for the cemetery owner.

Gilmore declined to disclose the cost of the project. According to a recently issued building permit, the value of the work is estimated at about $3 million. Construction is expected to be done by fall 2018.

The work comes on the heels of a 10-acre expansion at Valley of the Temples completed in 2015. That project included 3,700 burial plots, a cremation garden with 1,000 spots for various types of inurnment, 500 niches for couples wishing to be buried next to each another, a Japanese garden and a waterfall-fed stream in an area now known as Ocean View Terrace.

NorthStar bought Valley of the Temples in 2011 and also owns Diamond Head Mortuary, Hawaiian Memorial Park Mortuary in Kaneohe, Homelani Memorial Park in Hilo, Kona Memorial Park, Maui Memorial Park and Nakamura Mortuary on Maui.