Nearly two years after a Northwest Austin man deliberately crashed his single-engine plane into the Echelon I building, workers are close to finishing the exterior of the repair and renovation.

Built in the 1980s along with three other Echelon buildings, Echelon I is a 60,000-square-foot, four-story office building located at 9430 Research Blvd. near the US 183 and MoPac interchange.

On Feb. 18, 2010, Joseph Andrew Stack flew his plane into the second floor of the Echelon building, where the IRS occupied three of the four floors.

The plane crash burned most of the second floor and damaged the floor of the third floor so much that steel beams sagged from the heat, said Kevin Kimball, a principal with KVA Property Management, which manages Echelon buildings I and II. Congress Holdings Group manages buildings III and IV.

Workers repaired damage to the steel frame, poured concrete for a new third floor and installed a new ceiling on the second floor.

After completing the necessary repairs to the structure, Kimball said workers installed energy-efficient, tinted windows to prohibit ultraviolet rays from entering the panes. He said the window ledges were lowered to provide a better view of Austin.

"It will make for a nicer office atmosphere," he said.

The exterior should be completed by February, and the interior common areas, such as the restrooms and elevator, are scheduled for completion by the end of February.

The estimated cost of the renovation is between $8 million and $10 million. Echelon I was not a Class A office building when it was constructed, but Kimball said the renovations would boost its status to Class A because basically everything besides the frame would be new. The Class A status would be one of the top selling points to potential tenants, he said.

"There's no land for new buildings, and we're in an older area," he said.

KVA does not yet have any prospective tenants for Echelon I, but Kimball said a few companies have indicated interest in leasing the whole building. He said anywhere between one and 12 companies could fit in the building, and move-in could come as quickly as three to four months after signing the lease.