Add about three cubic yards of bark mulch at about $275 and reap a 536% ROI. Even among houses ranging from $250,000 to $400,000 in Georgia, Russell says an unfinished basement can add about $15,000 to $20,000. If finished, a basement can add much more — up to $40,000 or $50,000 to the asking value. If you have an unfinished basement, you might have room for storage, but you’re missing out on livable house for future patrons to enjoy — whether or not as a house workplace or house for entertaining. Creative choices might be converting a walk-in closet right …