How dose the siege workshop work in castle? What is it use for?

[zspiano]

Don’t understand from its intrduction notes in the game, repair the wall? Dose the wall need repair in this game?
Build siege engine means can destroy enemy siege equipments, anyway how dose it work and is it necessary to upgrade it to level 3?

 

[CalarTheMerciless]

Yes if it is attacked by siege engines ( they first target castle / town siege engines then the walls - there are normally 2 sets of walls for both castles and towns).