Breaking Objects

The rules can’t cover every possible object that adventurers might decide needs destruction, but some common items and situations are given in the Break Objects table.
    Some objects can be broken simply with a successful Strength check (usually a standard action). If an adventurer could conceivably break an object with his or her bare hands (or with a well-placed kick or shoulder), the DM should assign a Strength DC using the following examples as a baseline.

Strength check to...DC
Smash wooden chest16
Smash iron box23
Smash adamantine box30
Burst rope bonds21
Burst iron chains28
Burst adamantine chains35
Break through wooden wall (6 inches thick)25
Break through masonry wall (1 foot thick)35

Published in Dungeon Master's Guide, page(s) 64, Rules Compendium, page(s) 175.