Arson is suspected in a fire that swept through the historic Texas Governor's Mansion in June 2008 and left much of the 152-year-old home charred and severely damaged.
A group that made the first $10,000 private donation to rebuild the fire-gutted Texas Governor's Mansion is opposed to changing its look.
The Heritage Society of Austin will not support plans, unveiled in October, for a two-story addition to the 153-year-old building.
The Texas Historical Commission is in charge of issuing a permit for the expansion.
The June 2008 fire, as the mansion was unoccupied during renovation, has been ruled arson and so far no one has been prosecuted.
Society president Mandy Dealey says altering the exterior would threaten the architectural and historical integrity of the National Historic Landmark.
The proposed 2,000-square-foot addition would include an expanded family living area.
Gov. Rick Perry and his wife, Anita, are living in a rental house.