D&D 5E Demiplane walls

The demiplane created by the demiplane spell "...appears to be an empty room 30 feet in each dimension, made of wood or stone."

Are the outer surfaces actually wood or stone, or do they just appear that way?

Can you dig into the walls? What happens if you do? Can you effectively expand the demiplane by digging the walls, or maybe disintegrating big chunks of wall? Or does breaking a wall reveal some weird phenomenon? Or does something else happen?

Can you at least hammer nails into the walls to mount pictures, torches, ladders, etc.?

Do walls made of wood burn? Can you cast stone shape on walls made of stone?

I guess everything here is DM fiat. The spell does say it has a duration of only 1 hour, but you can go back to what you created the next time you cast it. Not sure what the one-hour duration is great for other than a short rest. Seems like a more powerful rope trick.

I may allow the space to be modified by the PCs to make it more homey. I may make the space beyond the walls similar to space or the astral plane to prevent expanding the space. I guess there is no harm in expanding the space to make meeting rooms and sleeping rooms, but the duration is still one hour. The spell does say you can travel to other peoples rooms you know. This may make a meeting room a good idea for a secret cabal or such, but people are trapped in the space if the spell ends. This may make paranoid people think twice and brings up the idea of air supply and such.

I guess you should get a feel on what the PCs want to do with it and let them if it is mundane, but reel it in once they want to break the system.

Oh snap, I hadn't even considered air supply...

But, the idea of a latrine that dumps your poo directly into the astral plane? Priceless!

The demiplane wall are a godsend. No tricking around with them possible, at least that's what I would rule.

I think there’s nothing beyond them and nowhere to go. I’d often thought of how you could use it to dispose of/trap an enemy that’s too hard to kill by luring them in. It would be tricky because you can’t choose when to close the door.

I wonder what passwall, stone shape or meld into stone would do. Honestly, I might rule that the walls are a facade and just for show. There is nothing beyond them.

77IM said:

The demiplane created by the demiplane spell "...appears to be an empty room 30 feet in each dimension, made of wood or stone."

Are the outer surfaces actually wood or stone, or do they just appear that way?

Can you dig into the walls? What happens if you do? Can you effectively expand the demiplane by digging the walls, or maybe disintegrating big chunks of wall? Or does breaking a wall reveal some weird phenomenon? Or does something else happen?

Can you at least hammer nails into the walls to mount pictures, torches, ladders, etc.?

Do walls made of wood burn? Can you cast stone shape on walls made of stone?

Click to expand...

I can't see the answer being anything other than DM Fiat. I think I'd answer some of your questions this way:

No, they aren't actually wood/stone but they behave very much like what they appear to be, so yes, you can hammer in nails and hang pictures on the wall. The wooden wall will even burn, but it won't ever actually burn up; eventually the fire will just stop leaving the wall looking like it always did (of perhaps it does look chatted but shortly regenerates back to new).


Most important, of you dig into the walls you quickly come up against the edge of the demiplane. Like, the wall is the thickness of drywall and beyond it is some weird phenomenon. Or maybe just empty space, but empty space is weird, too.

Beyond the wall Is void. Pure Nothing. In nothingness there is only insanity.

77IM said:

The demiplane created by the demiplane spell "...appears to be an empty room 30 feet in each dimension, made of wood or stone."

Are the outer surfaces actually wood or stone, or do they just appear that way?

Can you dig into the walls? What happens if you do? Can you effectively expand the demiplane by digging the walls, or maybe disintegrating big chunks of wall? Or does breaking a wall reveal some weird phenomenon? Or does something else happen?

Can you at least hammer nails into the walls to mount pictures, torches, ladders, etc.?

Do walls made of wood burn? Can you cast stone shape on walls made of stone?

Click to expand...

77IM said:

Oh snap, I hadn't even considered air supply...

But, the idea of a latrine that dumps your poo directly into the astral plane? Priceless!

Click to expand...

The answer to digging through the walls is going to be some form of "it doesn't get you any more room." There's nothing outside the room. That's the entirety of the plane, meaning it's the entirety of the universe in which the room exists. How it works doesn't really matter. The could plane wrap on itself Portal-like or hall-of-mirrors-like, so that if you disintegrate the left wall and a hole appears in both the left and the right wall and travelling through the left wall leads through the right wall back into the room. Or beyond the walls is a black or silvery nothing that can't be entered, or an open sky that can't be entered. You don't get more than 27,000 cubic feet. Physical space just ends, and the universe of the demiplane is no bigger than that room. It's up to you to decide if space is curved or flat. Personally, I'd make the floor and ceiling flat silvery nothingness that can't be entered, and the walls Portal-like and wrapping because that seems fun.

In general, I would assume that the air supply is continually refreshed. That seems well within the power of an 8th level spell (after all, rope trick appears to do it at 2nd level, and magnificent mansion can certainly do it at 7th), and, IMO, the DM shouldn't be looking for gotchas to spells of this level (beyond wish, of course). Let the spell be as powerful as an 8th level spell. Let it accomplish things that an 8th level spell would be capable of. It's competing with clone, control weather, earthquake, mind blank, tsunami, etc. The power of the spell is in creating an array of reusable 30 foot rooms. The details like whether there's light or atmosphere are trivial compared to the rest of the spell. I'd tend towards giving the PCs the benefit of the doubt, and if they find a truly egregious abuse then change your mind. It's not really a problem if an 8th level spell replaces rope trick and tiny hut, or semi-replaces magnificent mansion.

I would say that the walls function exactly like normal stone or wood and are no more than 1 foot thick. The walls can be damaged, destroyed, or otherwise used, and they may either regenerate themselves or remain destroyed when the spell is recast. I don't think it's important which you chose, so you might let the caster decide. I would say the demiplane can either be illuminated like tiny hut is (i.e., a light that can be toggled at the occupants' decision), or can be permanently lit or dark, at the caster's decision. These are all very minor details in the grand scheme of creating a demiplane.

Personally, I wouldn't let there be a trash hole to the astral plane, but I've seen players abuse such things. There's a reason that the bag of devouring is considered a beneficial magic item to experienced parties. Being able to permanently dispose of creatures and objects without destroying them is very powerful.

There is nothing beyond the walls, the demiplane ends there, so you can't poke a hole and walk outside or throw something out, there is no "out".

I can't say about whether I would allow poking a hole in the first place however. My first thought was to make the walls indestructible (but putting nails or carving the name of your sweetheart should not be a problem), and my second was to rule that doing enough damage would actually end the spell.

Putting nails in the walls cause you to lose your deposit. Put holes in the wall you are sucked out into the void never to return to the prime plane.