Stacking of Impact Weapons

[thistledown]

If you have a spiked shield where the spikes are enchanted with Impact,
and a main weapon enchanted with impact,
do the bonuses to bull rush stack with each other?

Impact:

This special ability can only be placed on melee weapons that are not light weapons. An impact weapon delivers a potent kinetic jolt when it strikes, dealing damage as if the weapon were one size category larger. In addition, any bull rush combat maneuver the wielder attempts while wielding the weapon gains a bonus equal to the weapon's enhancement bonus; this includes all bull rush attempts, not only those in which a weapon is used, such as Bull Rush Strike, Shield Slam, or Unseat.

[Kayerloth]

My guess and first thought is no. Bonuses of the same type don't stack as a general rule with Dodge and sometimes Circumstance bonuses being the only common exceptions to the rule.

[SlimGauge]

No. Once you hang shield spikes on a shield, you can bash with the shield as normal or with the spikes, but not both on the same strike. The damage the spikes do is based on the size of the shield they are attached to, but shield spikes are a weapon in its own right.

Core Rulebook wrote:

An enhancement bonus on a spiked shield does not improve the effectiveness of a shield bash made with it, but a spiked shield can be made into a magic weapon in its own right.

EDIT: I understand the question better now. You're not trying to have both the shield and shieldspikes enchanted with Impact, you're trying to have the weapon you're holding in your other hand enchanted with Impact as well as the shield spikes in you shield hand.

This would be effectively the same as having a weapon in either hand both enchanted with Impact (dual wielding). Since the impact property itself states that you only have to be wielding the weapon, not necessarily USING it during the bullrush, the question becomes "Is the bonus to bullrush from the impact property of wielded weapons an untyped bonus that stacks with itself, or is it a case of "same source" and doesn't stack ?"

[Seriphim84]

While I agree the answer is no, A shield and its spike are not separate weapons. They are a singular item. Your can Enhance a SPIKED SHIELD with offensive and defensive magics separately but you cannot enhance the offensive powers of your spikes and shield separately. A spiked shield can only make a piercing attack.

[Kayerloth]

Seriphim84 wrote:

While I agree the answer is no, A shield and its spike are not separate weapons. They are a singular item. Your can Enhance a SPIKED SHIELD with offensive and defensive magics separately but you cannot enhance the offensive powers of your spikes and shield separately. A spiked shield can only make a piercing attack.

Unless I'm mistaken (and Slim Gauge seems to have got it the second time around) he's talking about wielding both a spiked shield (offhand) and a weapon (primary hand) and both items are enchanted with Impact. Either way I think the answer comes back no they don't stack.

[SlimGauge]

Seriphim84, I was unclear. I only meant that offensive enhancements (the +N enhancement to hit and damage) go on the spike and are independent of and seperate from the defensive enhancements (+N enhancement to shield bonus) that go on the shield, and never shall the twain mix.

The choice of bashing or piercing must be my DM's house rule.

[Seriphim84]

Ah, then yeah, I am on the same page as you. They don't stack because they are the same. I think I misread that a bit too :-p

[thistledown]

Ah. I had missed the part about untyped bonuses from the same source not stacking. Slim and Kayerloth were correct in re-phrasing my question.