checks for busting through walls?

[Braininthejar2]

Imagine the enemy has a fortress.

The party wizard has had a summon monster prepared, and decides to go full pokemon - summon a fiendish centipede, and have it crash through the wall.

The centipede's strength is in the twenties, nothing to write home about. But it's gargantuan, the size of an old dragon. How does one check its chances of success?

[Piggy Knowles]

Breaking through walls is pretty hard, and would be a heck of a task even for a huge fiendish centipede. Your typical masonry wall starts with a break DC of 35, and only gets harder from there. You can find break DCs for various types of walls here: http://www.d20srd.org/srd/dungeons.htm#walls (even more types of walls can be found in the Stronghold Builders Guide).

You're pretty much always better going after doors, although those tend to be better defended for that same reason.

[ekarney]

For what it's worth, a hewn stone wall has a break DC of 50.

Unless that centipede has levels in dungeoncrasher and a few rage variants to stack I think it may have some issues hitting that DC.

[Braininthejar2]

So, it might be more effective serving as a siege ladder...

I take it there are no modifiers to take a creature's mass into account? ( there is a world of difference between a huge air elemental and a huge earth elemental trying to push down a wall)

[PoeticallyPsyco]

I think it would be reasonable to add your size modifier to checks to break down objects. You may be better served by having the centipede just attack the wall, trying to do enough damage to break through it bit by bit with each blow rather than all at once with a strength check.

[ekarney]

A str of roughly 60 would be required to hit the break DC of even 35 reasonably easily. With 40 being the absolute minimum.

As for simply damaging the wall enough to break through, then keep in mind that a stone wall has 8 hardness, and 7.5 - 15 HP per inch3 (Depending on whether the wall is reinforced or not).

Now assuming a 3ft thick wall and that you want to make a 3ft3 hole in said wall then you're looking at approximately 38,880 HP in that section. (Assuming I haven't totally screwed up my maths here.)

To further continue, again assuming I haven't totally screwed something up.

A hole in said 3ft thick wall, that's large enough to a medium creature to occupy comfortably is 75 cubic feet, which is 129600 cubic inches. Or 972,000 HP.


If I am wrong here, someone please correct me and I will straight up change my attitude on this because I don't want Braininthejar2 to be put in a bad situation, or think this is impossible. Because even though the math says this isn't a great idea, my DM style says to reward this sort of tactical play.

[MisterKaws]

A str of roughly 60 would be required to hit the break DC of even 35 reasonably easily. With 40 being the absolute minimum.

As for simply damaging the wall enough to break through, then keep in mind that a stone wall has 8 hardness, and 7.5 - 15 HP per inch3 (Depending on whether the wall is reinforced or not).

Now assuming a 3ft thick wall and that you want to make a 3ft3 hole in said wall then you're looking at approximately 38,880 HP in that section. (Assuming I haven't totally screwed up my maths here.)

To further continue, again assuming I haven't totally screwed something up.

A hole in said 3ft thick wall, that's large enough to a medium creature to occupy comfortably is 75 cubic feet, which is 129600 cubic inches. Or 972,000 HP.


If I am wrong here, someone please correct me and I will straight up change my attitude on this because I don't want Braininthejar2 to be put in a bad situation, or think this is impossible. Because even though the math says this isn't a great idea, my DM style says to reward this sort of tactical play.

Nah, hewn stone walls are 15 hp per inch of thickness per 10 square foot section. That's DMG page 60. right there.

Your typical 3ft thick stone wall has 540 HP, or 1080 when magically reinforced. Still pretty hard to break, just not unrealistically so. Three solid feet of stone do make quite a strong wall, of course.

[TotallyNotEvil]

One of the things I've noticed is how things, especially buildings, are incredibly hard to outright break.

Even for being with sufficient Strenght to theoretically lift the entire thing over their heads.

[Piggy Knowles]

One of the things I've noticed is how things, especially buildings, are incredibly hard to outright break.

Even for being with sufficient Strenght to theoretically lift the entire thing over their heads.

Meanwhile, a mook with an adamantine mace or a third level warblade and a few minutes of free time can make short work of all but the strongest nonmagical fortresses. The game is funny like that.

[MisterKaws]

One of the things I've noticed is how things, especially buildings, are incredibly hard to outright break.

Even for being with sufficient Strenght to theoretically lift the entire thing over their heads.

You can lift a phone. Can you crush it between your fingers?

[ExLibrisMortis]

If an item has lost half or more of its hit points, the DC to break it drops by 2.
Larger and smaller creatures get size bonuses and size penalties on Strength checks to break open doors as follows: Fine –16, Diminutive –12, Tiny –8, Small –4, Large +4, Huge +8, Gargantuan
+12, Colossal +16.
Technically, the bonus applies only to break doors, but I would definitely expand that to include all objects. That gives you +18 to break things, and 2d8+9 damage on the bite attack means stone takes around 10 damage per round; it takes 54 rounds to break through a 3' hewn stone wall, 18 rounds to break through a 1' masonry wall, or twenty rounds to take 20 and break the masonry wall outright (if you could get +23 to break things, you could spend 9 rounds weakening the wall, and then break it outright). Really, breaking through solid stone walls that thick in just five minutes isn't bad at all. It's just that D&D combat tends to be much speedier than that (and summons only last a very short time).

[Efrate]

Even with the plus 12, giant centipede at gargantuan has only plus 6 strength, so you still need a 17 or higher on the die to kool-aid man through the wall. Augment summoning makes it need a 15. That is not great but possibly quicker than mountain hammering or adamantine macing the wall.

A burrow speed that leaves a tunnel would be better to collapse or make a hole.

I would also allow an earth elementals earthern mastery to apply, possibly scaling with size. So a huge earth elemental would have plus 4 from earth mastery, plus 8 from size, plus 9 from strength so plus 21 on the check, plus 23 with augment. That is a roll of 12 needed to break which is better.

Greater would be a plus 5, elder plus 6. That seems reasonable.

[Doctor Awkward]

Imagine the enemy has a fortress.

Okay.

I'm imagining a typical fortress with ordinary masonry walls, 1 foot thick, hardness 8, 90 hit points and a break DC of 35 per 10 foot section.




The party wizard has had a summon monster prepared, and decides to go full pokemon - summon a fiendish centipede, and have it crash through the wall.

The centipede's strength is in the twenties, nothing to write home about.

Definitely not. It has roughly the same physical strength as a typical 6th level half-orc fighter wearing a belt of giant strength +2.
This is likely because while the centipede is extremely large, the extra strength is reflective of nothing but it's larger mass rather than a creature who possesses any noteworthy amount of actual musculature.


But it's gargantuan, the size of an old dragon.

Comparatively, an old red dragon-- the youngest and weakest MMI true dragon that can be of gargantuan size-- has a Strength score of 35, which reflects both it's massive size and a much more dense and highly developed muscular frame, and would be much more suited to the task of smashing through castle walls.


How does one check its chances of success?

That depends entirely on what kind of fortress the enemy has.

If, like I am imagining, it has a typical fortress, the gargantuan centipede would only succeed on a 17 or higher. This is assuming that the size bonus for breaking doors (http://www.d20srd.org/srd/exploration.htm#breakingItems) applies to all objects.1 This would give the centipede a +18 to their check, and a 20% chance to succeed per attempt. After 15 rounds this would be a 96% chance to succeed (which is arguably far better than trying to chew through the walls with bite damage). If the fortress is instead reinforced masonry, or anything with a Break DC higher than 38 then the centipede can never succeed.





1: The PHB seems to state this size modifier, which is the same as the Grapple modifier, only applies to breaking doors, which makes little logical sense. The Rules Compendium (in true RC fashion) tries to clear it up but does so in the vaguest way possible. On page 107, under the Breaking Objects heading, it states "When a creature tries to break something with sudden force rather than by dealing damage, use a Strength check (including a modifier due to size) to see whether it succeeds." This clearly states that there is a size modifier which applies to all Strength checks to break any object, but it does not state anywhere in the Objects section what that modifier actually is. If you head to page 116, where it discusses the Size of creatures, you'll find an updated table like what is seen on the SRD (http://www.d20srd.org/srd/combat/movementPositionAndDistance.htm#bigandLittleCreatu resInCombat), which changes the Grapple column to "Grapple/Break Modifier." This seems to suggest that this is the number referenced on page 107 that you add to any Strength checks a creature of the given size makes when it tries to break an object.

[RaiKirah]

In the recent Doomlord Iron Chef round I submitted a build that could hit the DC 50 break check for a 3' stone wall by level 10. I'll edit in the link momentarily. It turns out it's way easier to just do enough damage to break things as others have pointed out.


Edit #1: Caleb Praedo link: (http://www.giantitp.com/forums/showsinglepost.php?p=23310124&postcount=71)

Edit #2: Mis-stated level by which can hit DC 50 as 8 when it should have been 10

[ExLibrisMortis]

In the recent Doomlord Iron Chef round I submitted a build that could hit the DC 50 break check for a 3' stone wall by level 8. I'll edit in the link momentarily. It turns out it's way easier to just do enough damage to break things as others have pointed out.
And I think you weren't even taking advantage of your size bonus! That would cancel out the need for bull's strength/eagle's splendour in hitting the DC 50 check (not required, but elegant).

[RaiKirah]

And I think you weren't even taking advantage of your size bonus! That would cancel out the need for bull's strength/eagle's splendour in hitting the DC 50 check (not required, but elegant).

You know what, I think you're right! Even better :)

[Ellrin]

I feel like weight really ought to count for something. A gargantuan creature typically weighs somewhere on the order of 16-125 tons, according to the size chart. Sure, with a Str in the 20s, I’m not expecting it to bust through the walls Kool-Aid Man style, but it could presumably climb on top of them, and they may not be able to support its weight. Are there any rules for load bearing structures and weight limits?

[MisterKaws]

I feel like weight really ought to count for something. A gargantuan creature typically weighs somewhere on the order of 16-125 tons, according to the size chart. Sure, with a Str in the 20s, I’m not expecting it to bust through the walls Kool-Aid Man style, but it could presumably climb on top of them, and they may not be able to support its weight. Are there any rules for load bearing structures and weight limits?

That's engineering territory. They didn't think THAT far ahead.

[ekarney]

Nah, hewn stone walls are 15 hp per inch of thickness per 10 square foot section. That's DMG page 60. right there.

Your typical 3ft thick stone wall has 540 HP, or 1080 when magically reinforced. Still pretty hard to break, just not unrealistically so. Three solid feet of stone do make quite a strong wall, of course.


Thank you, the whole time I was writing I had this feeling that I was doing something wrong but couldn't think of what it was exactly.
Because 1,000,000 hp didn't sound right at all.

[Doctor Awkward]

I feel like weight really ought to count for something. A gargantuan creature typically weighs somewhere on the order of 16-125 tons, according to the size chart. Sure, with a Str in the 20s, I’m not expecting it to bust through the walls Kool-Aid Man style, but it could presumably climb on top of them, and they may not be able to support its weight. Are there any rules for load bearing structures and weight limits?

It depends entirely on the construction techniques.

Nearly everything you see in Gothic architecture-- from vaulted ceilings, to flying buttresses, and even arched doorways-- are designed for the practical purposes of evenly distributing the massive weight of stone and allowing for taller structures, rather than because they look nice.

Here's a YouTube video of a reinforced block of dry sand holding up a car. (https://www.youtube.com/watch?v=0olpSN6_TCc)

None of this is covered by the rules, though, but for comparison's sake, most modern residential homes can withstand the weight of 25 pounds per square foot so they don't collapse under the weight of snow.