Big objects such as castle walls often have extra resilience represented by a damage threshold. An object with a damage threshold has immunity to (almost) all damage unless it takes an amount of damage from a single attack or effect equal to or greater than its damage threshold, in which case it takes damage as normal.

The following are guidelines that the DM keeps in mind.

Level

Damage Threshold

AC/DCs

Examples

None

-

5-10

  • Shabby doors

  • Wooden objects

Sturdy

You need to deal at least 5 damage and that damage is taken as normal.

10-15

  • Desks or tables

Reinforced

You need to deal at least 10 damage and that damage is taken as normal.

15-20

  • Simple House Walls

Heavily Reinforced

You need to deal at least 25 damage and that damage is taken as normal

20+

  • Castle Walls

  • Reinforced Chests

Arcane Resilience


Resistant to all damage.

15-20

  • Common and uncommon magic items

Arcane Reinforcement

Immune to all damage.
Could be destroyed through special means that could require a special tool.

-

  • Rare and very rare magic items

Legendary
Reinforcement

These magic items are so tough that they cannot be destroyed in any conceivable way and must be locked away or perhaps even thrown into a volcano.

-

  • Artifacts

A player could do an investigation check to discover a weakness such as 'weak to bludgeoning' or weak to force damage or perhaps even 'weak to fire'.

Typically, magic items are not targetable when held by a creature.


Objects and Toughness

An object’s Armor Class is a measure of how difficult it is to deal damage to the object when striking it (because the object has no chance of dodging out of the way).

The following are guidelines that the DM keeps in mind.

Substance

Typical ACs / DCs

Typical Hitpoints

Cloth, Paper, Rope

11

1-10

Crystal, Glass, Ice

13

5-10

Wood, Bone

15

10-25

Stone

17

25-50

Iron, Steel

19

50-100

Mithral, Adamantine

21+

100+