Walls are the most straightforward form of fortification in Middle-earth, and are able to be built, by most factions, or already naturally stand at the stronghold of certain Fortress-maps. All wall-types in the BFME games are either Normal walls or Rampart walls.
Walls that are built from Wall Hubs are "Normal walls", for they are most commonly found in the progression of a long Skirmish, and are the only walls that can be constructed and repaired. These walls do not serve as battlements, are easy for siege engines to destroy, and can always be scaled and breached by Corsairs, Spiderlings, Corrupted Men heroes with the "Climb Wall" ability, and goblins.
Natural normal walls exist throughout the strongholds of Fornost, Amon Sul, Carn Dum, and Dol Guldur. At each of those places but Dol Guldur, the walls and their gates are taller in comparison to that of Wall Hubs.
Normal walls, whether natural or constructed by a faction, always have corner-pieces that are connected by wall-segments. (In the case of constructed normal walls, the Wall Hub itself is a corner-piece.)
The gates of normal walls, such as Arnorian gates or constructed Wall Hub gates, can be passed through by any unit type, as they lack a height-restriction.
Rampart walls are broad walkways upon which archers and even siege machines can stand, and attack enemies from. These walls are very durable against siege engines, and usually have 5000 health-points per "unit". Ladders and Siege Towers can only be used against rampart walls; but as a trade off, those who can scale normal walls cannot climb up rampart walls.
Only the fortresses of Helm's Deep, Minas Tirith, Isengard, and Minas Morgul are fortified with rampart walls. At Minas Tirith alone, trebuchet-expansions and Arrow tower expansions can be built among them. At Helm's Deep, only postern gates can be constructed. At Isengard and Minas Morgul, there are no possible wall-expansions.
Rampart walls are continuous, and do not have corner-parts.
The gates of rampart walls are more fortified than gates of normal walls, and have ceilings. However, because of those ceilings' height-restriction, Siege Towers, Mumakil, and Balrogs may not pass through them.