Charleston City Council Tuesday gave initial approval to adding a decade to a pair of tax incentives meant to help finance two large urban redevelopment projects, one in the downtown hospital district and the other in the Neck Area.

The plans call for extending tax increment financing districts, or TIFs. Under such plans, improvements - such as roads, sidewalks and parks - for the developments would be paid for by future tax revenue generated by the development.

One plan is the Horizon Redevelopment Project, aimed at creating new housing and a biotechnology research hub on 20 downtown Charleston acres, between Lockwood Drive and Hagood Avenue, from Spring Street to Fishburne Street.

The plan was set to expire in 2033, but will be extended to 2043.

Charleston County and the Charleston County School District previously voted to extend the TIF only for an additional five years.

The other project involves the potential redevelopment of land along the Ashley River in the Neck Area called Magnolia. The property previously was home to heavy industry and includes a Superfund environmental cleanup site.

That TIF was set to expire in 2029, but now will run through 2039.

Charleston County and the Charleston County School District also extended it for another 10 years.

City Council must vote on both extensions two more times before they are final. Dates have not yet been set for those votes.

Charleston Mayor Joe Riley said the Neck Area plan includes $500,000 for a community center in the Rosemont area. The money for the project was included at the request of Charleston County Councilman Teddie Pryor, Riley said.

But, he said, the city had been considering the project. "It's an appropriate use of TIF funds," Riley said. "It's a public building that will enhance the neighborhood."

Reach Diane Knich at 843-937-5491 or on Twitter at @dianeknich.