Question
how much room do i need if planting redwood along a fence?
I have approximate 3 feet between my cement driveway and the fence.
Will the roots lift the cement?

Answer
Redwoods have swallow root systems but they spread about 2-3 times the width of the crown so 3 feet would not be enough space for a redwood tree to live. The roots will more than likely not lift the cement but the tree will do poorly in this site situation. I would check with a local nursery and ask their advice on a substitute tree for this space.