Building a Dungeon

There doesn’t seem to be any entries on the stronghold price list for underground rooms or chambers.

I take it then, you just draw your proposed dungeon or underground stronghold and then pay 500gp for each 10x10x10 space–the price for a dungeon corridor.

Or do you build a hole somehow, pay the price for an above ground building, dump it in the hole and pay for corridors to connect them?

I just had this question myself, and found this unanswered thread, so. Here’s my thoughts:

Looking at Aryxymaraki’s excellent Mining Rules document in the downloads section, we find that a team of miners can clear a 10x10x2 (10 high, 10 wide, 2 deep) in a week, for 40 GP.

Sounds good - he arrived at that by assuming half the cost of building a stone wall was getting stone out of the ground, then adding some cost for bracing.

In fact, we can doublecheck that against D@W:C pg 81 - siege mining. A siege mine that has the chance of collapsing and killing everyone once a week costs about 5 cp per cubic foot excavated; these mines cost 2 sp per cubic foot.

Works for me.

So - excavating 200 cu ft costs 40 GP, we need 800 cu ft more to make our 10x10x10 room, that’s 40 * 5 for a total of 200 GP for a rough space, plus bracing.

That gives us a base cost of 200 GP for a hole in the ground - what’s the other 300GP?

The dungeon entry has a flagstone floor and “rough hewn walls”, which I’m going to take as meaning a rough stone bricked wall, rather than just the wall left where we stopped digging.

Other places on the 'net and at Autarch assume an interior keep wall thickness of about a foot; we’ll take that and run with it.

If we put a foot thick wall all around our room, our room becomes 9x9. We need to excavate a 12x12x10 space, in reality, to end up with a 10x10x10 room.

Our base “hole” cost is then 288 GP of a possible 500 GP.

Stone walls cost .25 GP per cubic foot. We’re making 4 11x10 walls (to meet up in the corners); that’s 110 GP.

We know our flagstone floor costs 40 GP from the book.

We’re at a total of 438 GP of a possible 500 GP.

Pretty darn close. We could drag another 40 GP out of doing the ceiling in flagstone; that’s 478 GP; that leaves us with 22 GP for various stuff; perhaps hiding the buttressing, or doing it in stone, or what-have-you. Frescoes of suffering PCs or empty torch sconces or big devil faces or whatever.

Or we could lose 20GP more by assuming we had to dig out a half-foot deep space for the floor and ceiling each, which gets us to within 2 GP of the 500GP cost.

So, given this, I’d agree that you figure out your cubic footage of dungeon and then pay 5 SP per cubic foot excavated for a dressed dungeon, plus whatever for stairs or special features.

The mage on a budget, or perhaps looking for a more authentic cavern experience, might just pay the 2 SP per cubic foot and save a bunch - I don’t know that the monsters who end up inhabiting the joint will care, but I would expect a ton of bad reviews on Yelp! from looting parties.

“I could forgive the kobolds on level one, I understand these dungeons are often franchised from the same mage and corporate often dictates the menu, but the walls were practically bare - just one hex over I could go to Barluk the Mad’s and get much more authentic near-death experience.”

Also, for what it’s worth, I think any mage player would be well served convincing their judge to use those Mining rules - mining out a vein and then reusing the empty space as dungeon is a killer idea.

I hadn’t even considered that, but that would be awesome.

My ever-increasing list of things to do, I think, now includes automating your mine pathing tables to see how viable that feels, and/or to see how often such a thing “pays for itself”, at least as far as “dungeon dressing” the main vein path.

Fortunately your tables don’t split the vein, so it’s casually programmable. (alternatively, vein “splits” happen if it turns back across itself)