Spokane developer Harlan Douglass is adding four buildings and about 440 rental spaces to his self-storage complex on North Foothills Drive, says Jon Johnson, its operations manager.

The complex, called Self-Storage on North Foothills, is located at 322 E. North Foothills Drive, and currently has 555 rental units ranging in size from 25 square feet to 480 square feet, Johnson says. The four new buildings will house units ranging in size up to 750 square feet, he says.

Douglass will handle his own construction, says Johnson, who declines to disclose the estimated cost of the project. Joe Wizner, city building official, says the project's permit application shows a cost of about $2.3 million. Wizner says the four new buildings will have about 53,000 square feet of space.

Johnson says the work should be completed sometime in May. He says the complex, which was built in 2005, has been successful, with an occupancy rate above 90 percent.

Separately, Douglass has begun work on another self-storage complex at the site of the former East Sprague Drive-In Theater, at 214 S. Eastern Road. Douglass bought the 6-acre site for $1.55 million in 2008, and it was reported then that he planned to build a storage facility there.

Johnson says the complex will have 1,250 rental units and likely will be called Self-Storage at Interstate 90 and Sprague. It is expected to open next fall, and will offer units ranging in size from 50 square feet to 200 square feet.

He declines to disclose the cost of that project as well. A building permit application filed with the city of Spokane Valley, however, shows a project value of $1.75 million, says city spokeswoman Carolbelle Branch. She says the project will have 186,000 square feet of space, with a total of nine buildings, four with two stories, and five with one story.

Johnson says the East Sprague complex will have four employees.

The drive-in theater closed in the early 1990s, and was demolished partly to accommodate the expansion of the Sprague Avenue-Interstate 90 interchange there, but the unused portion of the former theater site has remained vacant since then.

The architect for both projects was Bruce Jordan, of San Clemente, Calif.-based Jordan Architects Inc., Johnson says.