The Thieves Guild
A Collection of D&D 5e Resources
Spells for D&D Strongholds
D&D Strongholds, Bases and Hideouts

Siege Equipment

Siege equipment are large weapons, temporary structures, or pieces of equipment traditionally used to protect or besiege a castles or fortresses.
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Equipment
AC
HP
Range
Dmg *
Cost (buy) †
Cost (build) ‡
Crew
AC: 15
HP: 50
Range: 120/480 ft.
Dmg: 16 (3d10)
Cost (buy): 300 gp
Cost (build): 50 gp
& 4 days
Crew: 2 (1 min)

Ballista

AC: 15
HP: 50
Size: L
Dmg Immunities: poison, psychic
Cost to Buy: 300 gp
Cost/Time to Build: 50 gp & 4 days

A ballista is essentially a large heavy crossbow fixed in place. Before it can be fired, it must be loaded and aimed. It takes one action to load a ballista, one action to aim it, and one action to fire it.

Bolt. Ranged Weapon Attack: +6 to hit, range 120/480 ft., one target. Hit: 16 (3d10) piercing damage.
AC: 19
HP: 75
Range: 600/2400 ft.
Dmg: 44 (8d10)
Cost (buy): 1500 gp
Cost (build): 300 gp
& 30 days
Crew: 2 (1 min)

Cannon

AC: 19
HP: 75
Size: L
Dmg Immunities: poison, psychic
Cost to Buy: 1500 gp
Cost/Time to Build: 300 gp & 30 days

A cannon is a large tubular device designed to fire heavy cast iron balls over a considerable distance using gunpowder. In a campaign without gunpowder, a cannon may be a mechanical device built by gnomes/artificers or an arcane item created by wizards.

It takes one action to load a cannon, one action to aim it, and one action to fire it.

Cannon Ball. Ranged Weapon Attack: +6 to hit, range 600/2400 ft., one target. Hit: 44 (8d10) bludgeoning damage.
AC: 19
HP: 20
Range:
Dmg: 10 (3d6)
Cost (buy): 25 gp
Cost (build): 5 gp
& 2 days
Crew: 2 (1 min)

Cauldron, Suspended

AC: 19
HP: 20
Size: L
Dmg Immunities: poison, psychic
Cost to Buy: 25 gp
Cost/Time to Build: 5 gp & 2 days

A cauldron is a large iron pot, suspended so that it can be tipped easily, pouring its content on those below. Once emptied, a cauldron must be refilled — and its contents must usually be reheated — before it can be used again. It takes three actions to fill a cauldron and one action to tip it. Cauldrons can be filled with other liquids, such as acid or green slime, with different effects.

Boiling Oil. A large, cast-iron pot, suspended or hinged so it can be tipped over easily. The cauldron is typically filled with scalding hot oil and can be poured down murder holes or from the top of walls, falling onto a 10-foot-square area directly below it. Any creature in the area must make a DC 15 Dexterity saving throw, taking 10 (3d6) fire damage on a failed save, or half as much damage on a successful one.
AC: 15
HP: 100
Range: 200/800 ft.
(60 ft. min)
Dmg: 27 (5d10)
Cost (buy): 500 gp
Cost (build): 75 gp
& 7 days
Crew: 3 (2 min)

Mangonel (Catapult)

AC: 15
HP: 100
Size: L
Dmg Immunities: poison, psychic
Cost to Buy: 500 gp
Cost/Time to Build: 75 gp & 7 days

A type of catapult used to hurl projectiles at a castle's walls. The projectiles are launched in a high arc so it can hit targets behind cover. It takes two actions to load a catapult, two actions to aim it, and one action to fire it.

A mangonel typically hurls a heavy stone, although it can hurl other kinds of projectiles, with different effects.

Stone. Ranged Weapon Attack: +5 to hit, range 200/800 ft. (can't hit targets within 60 feet of it), one target. Hit: 27 (5d10) bludgeoning damage.
Ram
AC: 15
HP: 100
Range:
Dmg: 16 (3d10)
Cost (buy): 800 gp
Cost (build): 200 gp
& 10 days
Crew: 8 (4 min)

Ram

AC: 15
HP: 100
Size: L
Dmg Immunities: poison, psychic
Cost to Buy: 800 gp
Cost/Time to Build: 200 gp & 10 days

A large, heavy log that is encased in an arrow-proof, fire-resistant canopy mounted on wheels. The device is pushed by several people and propelled with force against masonry walls and wooden gates. It takes a minimum of four Medium creatures to operate a ram. Because of the gallery canopy, these operators have total cover against attacks from above.

Stone. Melee Weapon Attack: +8 to hit, reach 5 ft., one object. Hit: 16 (3d10) bludgeoning damage.
AC: 15
HP: 200
Range:
Dmg:
Cost (buy): 1200 gp
Cost (build): 200 gp
& 10 days
Crew: 16 (10 min)

Siege Tower

AC: 15
HP: 200
Size: G
Dmg Immunities: poison, psychic
Cost to Buy: 1200 gp
Cost/Time to Build: 200 gp & 10 days

A siege tower is a mobile wooden structure with a beam frame and slats in its walls. Large wooden wheels or rollers allow the tower to be pushed or pulled by soldiers or beasts of burden. Medium or smaller creatures can use the siege tower to reach the top of walls up to 40 feet high. A creature in the tower has total cover from attacks outside the tower.
AC: 15
HP: 150
Range: 300/1200 ft.
(60 ft. min)
Dmg: 44 (8d10)
Cost (buy): 1500 gp
Cost (build): 300 gp
& 30 days
Crew: 6 (4 min)

Trebuchet

AC: 15
HP: 150
Size: H
Dmg Immunities: poison, psychic
Cost to Buy: 1500 gp
Cost/Time to Build: 300 gp & 30 days

A trebuchet is a powerful catapult that throws its payload in a high arc, so it can hit targets behind cover.

Before the trebuchet can be fired, it must be loaded and aimed. It takes two actions to load the weapon, two actions to aim it, and one action to fire it.

A trebuchet typically hurls a heavy stone. However, it can launch other kinds of projectiles, such as barrels of oil or sewage, with different effects.

Stone. Ranged Weapon Attack: +5 to hit, range 300/1200 ft. (can't hit targets within 60 feet of it), one target. Hit: 44 (8d10) bludgeoning damage.
* The damage from siege engines ignore the damage threshhold of wall materials (see walls)
† This is the cost to buy a fully assembled item. These may be rare to find already assembled and quantities should be limited.
‡ This is the cost for parts and labor, including the cost of an experienced siege engineer. This also includes the time it would take to find resources, obtain and make parts, and then assemble the entire device. Some construction costs include: wood and lumber; metal nails, clasps, springs and other mechanical pieces; the metalurgy and blacksmithing of parts.

Building Siege Engines

Siege engines are large devices, and often require a small labor force and a skilled siege engineer. Any character overlooking the building of a siege engine will need to make a DC 15 Intelligence check using the modifiers below. Each siege engine requires a crew in order to function (see "crew" above) — a full crew is the minimum number of people required to build any siege engine (with a minimum of 2).

Condition Roll Modifier Time Modifier
Siege engineer involved Roll Modifier:  +5
Labor Force (see "crew")
¼ of the labor force, or less (no less than 2) Roll Modifier:  -2 Time Modifier:  x4
½ of the labor force (no less than 2) Roll Modifier:  -1 Time Modifier:  x2
Full labor force Roll Modifier:  0 Time Modifier:  No change
2x labor force Roll Modifier:  +2 Time Modifier:  -25% time
Lumber Availability
No lumber available (i.e. desert) Roll Modifier:  Can't Build
Lumber supply limited* (i.e. plains with a few trees, far from settlement) Roll Modifier:  -2 Time Modifier:  +25% time (to find lumber source)
Full lumber supply (i.e. nearby forest or lumberyard) Roll Modifier:  0
Metal Availability
No metal available (no forge, no nearby settlement) Roll Modifier:  -4
Metal supply limited (i.e. high metal demand, far from settlement) Roll Modifier:  -2 Time Modifier:  +25% time (to find metal source)
Full metal supply (i.e. nearby city, mine) Roll Modifier:  0
* The DM should use their discretion when deciding how scarce lumber is, and change the modifier and time as needed. The DM may also wish to add a cost modifier when lumber is scarce.
† The DM should decide if metal parts can be replaced with wooden parts. This may not be possible in a siege engine like a catapult (which requires a metal spring and coil), or a cast iron cauldron.
‡ Various factors can affect the metal supply, such as a kingdom being at war, a problem with trade routes, rust monster infestation. The DM may also wish to add a cost modifier when lumber is scarce.

Siege Attack

Siege Engine Attack Modifiers

Ranged siege engines are large devices that often require multiple people to use. As such, the DM may allow additional modifiers to the attack (see the table below).

Condition Modifier
No line of sight to target square Modifier:  -5
Successive shots (crew can see where most recent misses landed) Modifier:  Cumulative +2 per previous miss (maximum +10)
Successive shots (crew can’t see where most recent misses landed, but observer is providing feedback) Modifier:  Cumulative +1 per previous miss (maximum +5)

Missed Siege Attack

Optional Rule: When a ranged siege attack misses their target, there is always a chance that it may hit another target. When the attack misses, the DM should roll a d8 to determine which direction (or quadrant) the projectile goes, and then roll a d10 to determine the exact square (on a 10, the projectile breaks or explodes in the air, and does not land).

Missed siege attack, quadrant and grid 1. Roll a d8 to choose a quadrant.
2. Roll a d10 to choose a specific 5 ft. tile within the quadrant.
    (if a 10 is rolled, the projectile breaks/explodes in the air, and does not land)

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