I will be installing maple flooring in our living room starting along a wall that contains a door from the front entry hallway. There is an existing threshold that matches the height of the existing hardwood flooring in the hallway. The new flooring will be at the same height as the hallway. How can one allow the new floor to meet the existing threshold without being concerned there is no expansion gap? Must I create a new threshold board over the old one with a 1/2 inch gap.beneath it? Any advice would be appreciated.

No expansion gap necessary if you leave a gap at the other side of the floor.