Although the shingles currently on the roof are not original to the house (wooden shingles, depending on the type of wood, have a 25 to 50 year lifespan), they are the same shape, size and material as the ones George Washington used. It was through research and physical evidence that the roofs original appearance (and paint color) was discovered.
The roof you see today was installed in 1994 and uses over 60,000 hand rived cypress shingles. A froe is used to split the thin shingles off of a larger block of cypress. After the shingles are removed from the block they are then rounded with a saw to give the "fish scale" appearance to the roof that George Washington liked so much.