A structural engineer who studied the 120-year-old Old Courthouse Museum in Sioux Falls has determined its attic is not strong enough to be used as a storage facility.

Museum officials have moved some collections into the basement, particularly heavier items such as tools, but the basement presents other problems for artifacts, including humidity. That has spurred Minnehaha County to begin planning for a new archive center in north Sioux Falls.

The county and city, which are partners in Siouxland Heritage Museums, plan to begin design work next year for a facility on donated land. Siouxland Heritage Museums director Bill Hoskins says if a new facility is not built soon, officials likely will have to find rental space.