Double Knockback followup

[Gary]

Suppose a character's casual str is enough to knock down a barrier. Do you still subtract the def of the barrier before calculating knockback?

[Steve Long]

The same rule would apply. I don't see that Casual STR has any particular bearing on the situation, though the character could use his Casual STR to take down the barrier before making a HTH Combat attack that causes KB and just avoid the problem altogether. ;)