Is there a base chance to block with shield?
negative, not unless you have a boon for blocking (aegis) or using your blocking skill.
I enjoy it with mace as 4 out of my 5 attacks mitigate and the base attack still hits pretty hard.
In the last trait line at 10 points there are two traits that work well with shield. One is reflect projectiles on block (which WvW you can kick back a ton of damage), and the other, the one I enjoy for upping damage quick, is stacking might on each block.
Facing a horde of 10+ mobs (I am tank) you get a ton of might quick (also am traited to build adrenaline each time I am struck), I then swap to hammer to smash with f1 and blow the kitten out of everything around me. It is a really nice table turner when traited for it.
I am going 20 into the trait line eventually so I can use both, my block will be God mode.
Aside from adding some defence, it’s only useful for skills.
Thanks for the replies all.
@DaisyRogers-thanks for suggestions. Had been looking at the reflect projectile definitely as that seems to always bee needed in dungeons. the might stacking would be useful as well in a lot of situations.