Black Ice-Reinforced Wooden Stairs

Description
Any warrior with even a little battle hardening will agree that the safest ground to defend is the high ground. And if there is no high ground to defend, make it yourself. Stairs are a necessity once buildings grow beyond a certain size. They provide points of natural defence and easy access to higher floors and rooftops (which make excellent archery platforms). Their only weakness is the material upon which they are built - if the high ground is brought crashing down then it no longer serves a tactical purpose. Black Ice-Reinforced Wood is one of the hardest building materials that can be created in the Exiled Lands. Weapons barely chip it and even explosive powder is not enough to weaken it in a single blow. Siege weapons or divine intervention are really the only way to bring down walls this strong.

Repair
Repairing  requires up to:
 * 5
 * 3