Fortifications are a special type of Improvement.
The Fortification works that surround an area are assumed to enclose the two acres of a hall (with or without a motte), its Stable and Outbuildings, and enough room inside for the commoners and their livestock.
At this point in time there are very few stone fortifications. All which exist have been maintained since Roman times.
Bailey
A Bailey combines several protective works.
Works: Ditch and Rampart 3, Palisade 3, Gate -2, Simple Gateworks 1
Cost: £10
Defense Value: 5
Ditch and Rampart
A Ditch is a trench, ten to twenty feet deep, thirty feet wide, and long enough to surround the enclosure. Its sides slope, to prevent crumbling. The dirt is piled and shaped on the inside of the ditch to double the height there, giving attackers a steep ascent of twenty to forty feet. Assault Gear is still required to attack it, used to fill in the ditch and go over the Rampart.
Works: Ditch and Rampart 3
Cost: £3 per 1000 feet
Defense Value: 3
A Palisade is usually erected atop the Rampart.
Note: One Gate is required per two-acre enclosure.
Gate, Normal
All fortifications need a Gate to allow entry and exit of its inhabitants or users. A Gate in these descriptions indicates the necessary gap in the works, with a hinged, closable wooden “door.” These are the weakest point of any fortification. They can be protected by more effective Gateworks which are additional, and described below.
Cost: £0
Defense Value: -2
Gate, Postern
A Postern Gate is a small gate that allows one person at a time to go through. Horses cannot pass through Postern Gates. Larger castles usually have one of these to facilitate supply, but they are never used as the port of entry for inhabitants.
Cost: £0
Defense Value: -1
Gate, Large
Large Gates are generally found in cities, or where a lord flaunts his wealth at the expense of safety.
Cost: £0
Defense Value: -3
Gateworks, Simple
A Simple Gateworks includes heavy timbers, powerful hinged gates, large logs and fittings to hold it closed, murder holes through the overhead walkway, and more reinforcement to keep it intact.
Cost: £2
Defense Value: + 1 to a gate
Gateworks, Complex
A Complex Gateworks includes everything that a Simple Gateworks has, plus a drawbridge that can be raised and lowered (and the mechanisms to work it). These cannot be used on a Postern Gate.
Cost: £4
Defense Value: + 2 to a gate
Moat, Wet
A ditch filled with water is called a Wet Moat. A river or large stream must be conveniently located to fill it. These costs must be added to the cost of the obligatory ditch. Wet Moats are far less common than movies would have us believe.
Work: Wet moat
Cost: £2
Defense Value: +4 to ditch
Motte
A Motte is a large man-made pile of dirt and rubble — or a natural feature — with a top big enough to hold a lord’s hall and a log palisade. The average height is about thirty feet above the bailey. A wooden staircase often goes up to the tower, and can be removed in case of an attack on the motte.
Works: 30’ tall mound
Cost: £5
Defense Value: 4
Motte, Double
Sometimes a natural feature (or a particularly paranoid lord) raises a Motte of up to double the normal size.
Works: 60’ tall mound
Cost: £12
Defense Value: 6
Motte, Fortified
A simple hill is a good defense, but mottes are also generally crowned with a Palisade and Gateworks, with the lord’s Hall (not included in the cost) enclosed within.
Works: Ditch and Rampart 3, Palisade 3, Postern gate -1, Simple Gateworks 1
Cost: £11
Defense Value: 5 (9 including motte)
Motte-and-bailey Castle
This type of fortification is common enough to be classed as “standard.” It has the two-acre Bailey. Again, note that in the tiny space of the Motte, the tower contributes to its DV. The Motte and its Tower feature concentric rings of defense, (see below).
Works, outer: Bailey 5
Works, inner: Fortified Motte 9, Wooden Tower 2
= 11
Stronghold: Wooden Tower = 2
Cost: £36
DV: 5/11/2
Rings of Defense: The Motte-and-Bailey castle has a unique feature among all these fortifications. Note that the Motte defense (normally 9) is raised by the Wooden Tower (2). It contributes because the area of the Motte is so small that defenders in the hall can help the defenders at the Motte wall with archery and observations.
If the Motte is successfully stormed, the Tower still remains as a last-ditch defense. It acts as a concentric holdout.
Palisade
This wooden wall is at least fifteen feet tall, above the ground. The sample here is for two acres because that is the average size for Motte-and-Bailey Castles.
Works: Palisade 3
Cost: £ 5 per 1000 feet
Defense Value: 3
Note: One Gate is required per two-acre enclosure.
Wall, Rock
This is a simple wall of rock held together with clay, not made with excellent engineering skill and concrete (whose formula has been lost). It is about fifteen feet tall, with a wide base of packed dirt and rubble covered by stone. It is sturdy, efficient and useful, but not as effective as the carefully constructed curtain walls that use concrete. Its primary value is that it cannot be burnt — but it is much more expensive.
Works: Rock wall 3
Cost: £10 per 1000 feet
Defense Value: 3
Note: One Gate is required per two-acre enclosure.
Tower, Wooden
A Wooden Tower can be added to the defense of any Bailey or Enclosure. One can be added for every 200 ft of wall perimeter. Thus a Motte-and-Bailey has five potential locations for a tower. However, the Motte occupies one of these spots, as does the gate and its defenses leaving space for three Towers.
Cost: £15
Defense Value: 2
Town Enclosure, good
A town enclosure has the same fortifications as a Bailey, but is larger. The average-sized town, which is often the primary fortification for an estate lord, is about four acres.
Works: Enclosure
Cost: £14
Defense Value: 5