How durable is a Floating Disk?

Question

If I create a floating disk, and another creature or person decided to try to break it, how durable is it? Does it have the hardness of a wall of force?

Comparing it to other force spells, such as Instant Weapon which states a hardness and health, as well as Wall of Force and Resilient Sphere have a DIFFERENT hardness, and Force Sword clearly states it cannot be attacked. Floating disk states neither of these, and as a result I find it unclear as to which behavior this spell falls into.

Instant Armor states nether, only that it acts in every way like the armor it replicates, so presumably has the HP of the armor when sundered. (However armor hardness is based on material so im presuming this replicates standard materials?)

Answer 1

The floating disk is an Evocation (Force) effect, meaning it is not strictly defined as an object. It extends into the ethereal plane and is immune to all damage. The only way to "destroy" it is via the use of specialized magic (e.g. dispelling/disjunction), or by meeting one of the conditions that are stated in the Floating Disk spell description, i.e. [emphasis my own]:

The disk winks out of existence when the spell duration expires. The disk also winks out if you move beyond its range or try to take the disk more than 3 feet away from the surface beneath it. When the disk winks out, whatever it was supporting falls to the surface beneath it.

So, the smartest way for an enemy to attack the floating disk would simply be to overburden it somehow (i.e. jumping on top of it in full plate?), attempting to pick it up above the 3 ft limit (an interesting question in and of itself...), or pulling the caster out of range of the floating disk.

Answer 2

The Floating Disk is invulnerable.

I'm constructing my answer based on a couple of things:

First, spells that create an unusual object that is vulnerable to damage typically give stats for just how hard that object is to damage. For summoning spells these are usually a stat block, but if not, the spell will tell you how to damage it. For example, look at Unseen Servant:

The servant cannot attack in any way; it is never allowed an attack roll. It cannot be killed, but it dissipates if it takes 6 points of damage from area attacks. (It gets no saves against attacks.)

Because the spell tells us exactly how you damage the Servant, we can assume that it is vulnerable to damage. Compare this to spells like Arcane Eye or Umbral Weapon, two spells that create similar projections but don't give hit points or AC for the projection, because it is not possible to damage them with conventional means (although they could still likely be Dispelled). When we view it this way, Floating Disk clearly falls into the latter category.

Second, what the spell creates is not an object in the physical sense. It is a projection of force, as detailed in the spell description:

You create a slightly concave, circular plane of force that follows you about and carries loads for you.

It's kind of like asking, how durable is a Magic Missile? The answer is, infinitely. Or 1d4+1 damage, depending on what end of it you're standing.

Answer 3

I think the other answers cover RAW pretty well. If you wanted to calculate Hardness and HP using other similar objects, these might help:

Based on the spell description, "The disk is 3 feet in diameter and 1 inch deep at its center."

You could say this is equivalent to a large shield, which would have 15 or 20 hit points according to the rules for damaging objects. Choosing a hardness of 20 as per Instant Weapon seems fair to me since it is only a level 1 spell. This would be the equivalent of "Adamantine" which independently lists as 40hp / inch of toughness, so you could rule that it has 40 hp in this scenario.

You could also say it is similar to a wooden door, and use the DC for breaking objects with strength checks instead. I feel like this approach would be better for an improvisational ruling to keep the action going in a session.

According to the rules for damaging objects, the DC to break down a barred door is 25, if it has arcane lock cast on it it raises to 35. You could choose a different base DC but I think setting a DC and then having the character make a strength check would be reasonable.