Warding a building so that it can exist entirely underwater


What are the logistics of warding a building against water so that it can exist on the bottom of a lake?

I imagine that a circle ward would almost certainly decay over the course of decades, no matter what sort of material you make it out of.

So you would probably need to either enchant the structure its self, or build an item into the structure that casts a structure target spell with an environmental trigger and maintains it.

How would people do this for maximum longevity? What are the implications of opening doors and windows in such a structure?

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Maybe a "lungs of the fish", just with bigger target and the item itself concentrate. then you also can open doors and windows ...


Hmm. What are you trying to achieve, exactly?
One can easily create a building that will last for centuries underwater without resorting to magic.
Or is a "normal" building about to be transported underwater, and you want to protect it?
Or do you want to create a water-free zone underwater?

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I would do it as you suggest:

Palace of Poseidon
ReAq 39
Penetration 0
Constant effect
R Touch, D Sun, T Structure
This jade door, installed at the entrance to an underwater building, prevents water from entering the structure.
(Base 5, +1 Touch, +2 Sun, +3 structure, +1 level for 2 uses/day, +3 levels for environmental trigger)

Strictly speaking, opening a door or a window shouldn’t break the effect. Water would still be kept out. But that feels like a GM call and I might draw the line at large windows and doors.


Our Covenant is the second (or third) such structure located on the site.
The previous main covenant building (A tower) has been established as having once resided on a nearby island, but that island was sunk.
The interior of the building is dry and has breathable air due to some sort of ward, but we never really investigated what that protection was that kept the water out.
It's got to have been something that survived over 50 years without any sort of maintenance.

We are planning on setting an adventure there and want to make sure that the players can adequately investigate the ward and that it makes sense.

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Ahh... so you are looking for a plausible backstory for a "normal" building that has been dry and filled with breathable air despite being underwater for 50 years. So it need not be a Hermetic effect, right? A Divine miracle or a pact with some water spirit - or with the lake itself - would all be feasible explanations.

One crucial, further question: is all water kept out, or just the lake's? This might seem a small detail, but it makes a lot of difference: in particular, a structure into which you can't bring any water all, for drinking, cooking, or washing is not really fit for habitation ... which implies certain conclusions. An Hermetic effect that only keeps the lake's water out is ... possible but trickier.

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As it was a Hermetic Covenant building, the effect is likely Hermetic. As there were no other major powers at play during the time it was built to when it was sunk. (Previous powers included groups that were likely proto-Diedne and followers of the Spider, but they were gone before the Hermetic covenant building was constructed.)
I imagine that this was a contingency put in place before the building sunk (as the sinking was foreseen as a possibility, but was very sudden) so it probably would require some water to be allowed in.

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There are many possible solutions. The magi in my saga would probably have approached the problem the following way.

First, they would have come up with some stopgap solution while the island was sinking to keep water outside the structure - probably sealing the doors and windows with tar or something like it - to be removed once a more permanent solution was found. Then, they would have asked the lake itself to please stay out of the tower (keeping the air bubble trapped inside) via Voice of the Lake, possibly cast by borrowing a casting tablet from some other covenant, or having some visiting Aquam mage ask the lake in their place. Then, they would have made sure the air inside stayed fresh via a few judiciious applications of a D:Ring Chamber of Spring Breezes cast spontaneously without fatigue (quite feasible since it's still a first magnitude spell).


The covenant Aegaea in the Theban Tribunal seems to get away with it by being in a Faerie Regio at the bottom of the sea. It's still underwater, but the water is remarkably Air-like. But could an underwater covenant be shifted into a Regio that is actually dry? Would it have to be built underwater and then shifted? That would be difficult. Aegaea could also just be the result of the divine magic of the god Poseidon and be something that mortal wizards can't duplicate.


ReAq and ReAu (to circulate the air inside the building) have obvious spells, the question seems to be primarily about durability, which has a few obvious answers-

circle duration: a stone circle in water could last for centuries, especially in still water, though the type of rock is also a potential question- granite or marble will be much better options than say limestone.
Enchanted items with target structure, so long as there is no flicker effect.

The bigger issue with a magic circle is not crossing the barrier with the material in question- for example getting rid of waste water, or making certain you have enough liquids in the building to drink.

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Keeping ALL water out is easy, but truly Hermetic effects aren't generally intelligent enough to handle the needs to both acquire and resist water unless you have a lot of them. Of course, if people were living here a long time, they may have had the time and resources to do all that work. You could, for example, split the covenant into sections warded separately, and have a very sturdy, ideally otherwise watertight outlying building (probably built with a ritual, since I don't think medieval construction could be sufficiently water-resistant everywhere except the intended entry point) with a pipe or window whose water ward is enchanted to be able to turn on and off. Then you could put down a big basin or dig a well or something, and catch lots of water, then reactivate the ward. You would probably need to do this at the specific building(s) where you want the water used.

This method won't work for disposing of waste water, so you'll want a PeAq effect to deal with that. Maybe also Pe(some other stuff), since I don't think PeAq alone could dispose of feces and whatnot, and there's nowhere else to shovel those off to.

How does this place get food, metal, lab supplies? You can't magically create anything permanent and capable of sustaining a population without a Ritual, so unless the covenant is extremely vis-rich, you need to have constant supply lines with the surface, or somehow figure out a way to farm underwater in light of the warding-out-water thing.

No, all of this is to say I'm with the other posters - doing this with purely Hermetic effects is going to be almost impossible.

However, you can use purely Hermetic effects to get someone else to do it for you! See the previous points about making deals with water spirits or the lake itself. If the magic is being intelligently managed on the fly, then suddenly all of this becomes a lot easier.

Iirc, some Mysteries or other slightly-off-Hermetic Virtues would be well-suited to directly binding such a water spirit to the location, if you wanted it done by force rather than by way of deals that need to be upheld, but I think having a local spirit whose terms you need to stick to to keep your covenant protected and provided for sounds like a great Hook.


Once you have the ward set up, there are several way to handle the logistics of supply and waste. One option for water would be a ReAq effect to teleport it either directly from the lake, or from another source, whether personally or using magical devices. Extrapolating from ReCo guidelines, this might be a level 20 effect if transferred from the lake, Base 10 to transport five paces, +1 Touch, +1 Part. Then dig a well right by the edge and stick your hand into the water. If you wanted it from somewhere other than the lake, it would be a level 25 effect if within a league, level 30 for 7 leagues, or level 35 to remove distance limitations. Once the water is inside the ward, it can be transported to wherever it is needed, or kept in the well.

As for other goods, you might transport them on the lake, then seal anything vulnerable to water before lowering them down to the covenant, either using magic or with a boat and a crane, or even just dropping it a short distance outside the ward, letting it sink, and then hauling it once it reaches the bottom. Another alternative is to construct a tunnel, whether a mundane one in the bedrock, or one similarly warded against water. Of course, these other supplies may also be teleported. Perhaps the most effective way of all would be to use a Portal, though a Hermes' Portal requires a yearly ritual and thus, vis.

As for waste, destroying human and animal products is a level 4 effect, and waste can be considered a "product". There is also, depending on what infrastructure is used for other logistical purposes, the option to use it to transport waste out, as well.

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One option for water would be a ReAq effect to teleport it either directly from the lake, or from another source, whether personally or using magical devices.

Noble's Parma, but I'm pretty sure warding an area against something also keeps Rego effects and the like from transporting that type of material or creature into or out of the area.

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That would depend on whether it's warded from being in the area, or from passing through the boundaries of the effect, as well as whether you have transportation spell work by way of teleportation or instant movement. If the whole area is warded, any water inside will just be expelled into the lake.

As for whether transportation spell work by instant movement or teleportation, this is addressed in TME, and while it does mention the option of limiting transportation magic so that it can't pass through barriers, but brings with it worn items, it marks this as an optional rule, which would indicate it isn't intended as the baseline, though which you use will depend on your troupe.

Edit: In addition, while I'm not too familiar with the physics of Mythic Europe, you might be able to use CrAq to make a spring inside the ward, depending on how springs actually work.

I'm nowhere near as well read in all the expansion books, tribunal materials, and such as some others here, but I thought it wouldn't be beyond hermetic magic. I'm asking in ignorance here, as it seems accepted wisdom by most posters.

Couldn't the magi add an extra magnitude for complexity and use a spell to prevent all water from Lake {insert name here} entering?

I'm thinking wards and summoning with demons and fae, if one had a demon or fae's name, one can specify the demon, fae, etc. It sets some precedent about specifying certain things the ward works against, while not others.


Most of these replies seem to assume you need "ward against mundane water." But, how big is the lake? If you target the lake's water itself with Rego Aquam, use "control liquid in an extremely gentle way" to keep it out of the covenant and use the extra magnitudes to increase the effect to Boundary + size modifiers.

If the spell was to stop, anyone in that building would not experience a gentle flow of liquid. I like the thinking, however, I'd suggest only 1 magnitude (which is still useful) is gained, as the level 4 guideline "Control a liquid in a forceful but calm way, such as a fast but constant current." seems more appropriate.

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The problem with T:Boundary is that it makes the effect a Ritual. However, T:Part on the water surrounding the covenant - to keep it where it is, neither flowing into the building nor mixing with the rest of the lake - would seem to work.


I think this is a tricky issue. On the one hand, we do have wards that keep out only a very narrow subset of the Form - for example vermin - without adding extra complexity. In fact, a Ward against Water is not a Ward against Aquam ... it allows wine in! On the other hand, whether you can restrict container spells to work only on an arbitrary narrow set of entities can be easily abused - it allows "information-gathering via pink dots".

Personally, I'd allow it for wards - and without any added magnitudes - as long as one can visually tell that narrow set apart, or perhaps have an AC to it, following in spirit the Limit of Arcane Connections. But I think not every troupe would see it this way. Please note that this is about restricting the spell to work forever only on that narrow set, not about restricting it "on the fly" (though the difference fades with Spontaneous magic); so you can create a formulaic ReCo ward against your devious apprentice, but it will forever be useful only against your devious apprentice. "On the fly" restrictions seem to require specific abilities, at least in the case of Wards, such as those of the Columbae.


I never personally fuss myself with pink dot conundrums.

If a certain interpretation is good for story, and not a gross abuse of the rules, I'd allow it. If someone else tried to use that interpretation to abuse a rule later, it would fail.

If challenged about my lack of consistency, I'd say, I, and the weirdness that is magic, may not be 100% consistent, be we are consistently 100% not stupid. Pink dot should never get beyond a thought exercise. Any SG should say "Just stop it. Stop it now".

At this point though, I am thinking the answer to the OP, after a side off topic ramble is, if a magi wants to ward against the specific lake only, that's an option if the SG approves. Not all SGs would.

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