The principal material used in its construction was stone. While documents agree that the stone was quarried locally I’ve never seen anything that was able to identify the type of stone.
If you’re not familiar with stone construction it is very similar to brick masonry construction. The stone is shaped and put in place with a mortar to secure it in place. In some locations where the joints would be too large, the pieces would be locked into place by other shaped pieces like a puzzle.
Minor floors were constructed of timber beams with plank flooring.
Many of the walls that aren’t stone were plastered.
The roof has changed over time. Originally the roof was probably rolled or beaten copper, but it has seen replacements of lead and tern sheets. My understanding is that it is almost completely copper today.
A lot of structural improvements have occurred throughout the years such as additional buttresses but wrought iron bars and chains were added throughout the structure to keep it from shifting.
I have a feeling that I may have gone too far in my description already, and will stop at this point.
MKDesign 