Constructs (except Inanimate and Animated Objects) are a pain to deal with on most characters, as they tend to have DR and resistance to magical damage types. The particularly awkward ones are golems, which have 50% absorption for
all magical damage and high DR to boot. Here's a quick summary of how golems interact with different damage types:
- Poison and Negative damage are flat-out useless against any constructs.
- Fire, Acid and Lightning damage deal half damage to most golems, but heal one type of golem each (Iron, Clay and Flesh respectively.)
- Other types of magical damage (except Rust, which we'll get to in a second) deal half damage.
- Physical damage is unaffected, except by DR.
Constructs almost exclusively have Adamantine DR, so any melee or ranged character with an Adamantine or Metalline weapon will deal normal damage to them. The best class to take them out, though, is definitely Artificer.
Artificers get access to a set of special spells which deal Rust damage, a special type of damage which
only works on constructs. To compensate for how situational this makes them, these spells deal excellent damage.
Accordingly, if you want a character for the express purpose of breaking Constructs, build an Artificer with a high Spellcraft, then grab a Reconstruction item to boost your rust spell power.
(Playing a caster that isn't an Artificer? Physical damage from
spells isn't affected by DR, so try a spell that deals Bludgeoning, Slashing or Piercing damage - Meteor Swarm (not on Iron Golems), Blade Barrier, Blightcaster Thorn spells or the like.)