I’ve been putting together what I feel makes the most sense for rules concerning building things in an RPG. So let’s throw words to talk about it.


I am a large fan of the game Minecraft. I play it a lot. It’s got a lot of interesting things going for it, but one of my favorite bits is how it is a game about building. You can do all sorts of other genres in Minecraft, of course, but at its core, it’s a cooperative friendly game about improving things. There is this feeling that the game has that I don’t catch in other places. Sometimes, I’ll play games like Age of Empires or Starcraft and get a bit of that feel, but these games are zero sum games, we can’t continue growing forever. Eventually, we’ll be out of room, out of resources, and sometimes, people come and attack us. (Part of my dislike of competitive game play may be the fact that I’m not great at it.)

It doesn’t fit all styles of gameplay, but, sometimes, I get the jonesing in D&D to develop an area instead of just passing it by. But I haven’t found any system that has really fit my criteria for what makes a buildy game work. So I’ve made my own.

Matt’s Criteria

I’ve looked through a lot of resources over the years, trying to track down the rules I want. Everything has had flaws, so let me see if I can identify the key points of a good system

  1. The system should be simple for players and GM.
  2. The system should be accessible at any level of gameplay.
  3. The players should be able to interact with it by throwing money at it.
  4. The players should be able to interact with it by throwing no money at it.
  5. The system should be able to incorporate all sorts of buildings.
  6. Players should be incentivized to participate both in needing buildings and actual construction
  7. The system should be portable to other systems


This should be the goal of anyone designing a system that they will be using themselves. I mean, complex systems bring results closer to Verisimilitude, but that is rarely my goal. I want things that I can remember the rules without effort. Interacting with the rules should keep the game moving, not bring it to a standstill.


A lot of buildy systems seem to think of construction as high tier content. This has been the case since the first editions, where characters of a certain level attracted followers and built bases. Since then, it’s been assumed that people building a castle need to be rich. Which, fair enough, I guess. But while high level play should allow players to create castles, the same rules should allow low level characters to build a mud hut or a cottage.


If the players can afford it, and if they want to, they should be able to just spend money and then the structure will be built off-camera. This will be expensive, of course, but a lot simpler than doing the work themselves.


If the players can’t afford it, they should be able to create structures without paying a single red cent. This means they will have to source their materials and do the work themselves. This option is also useful if the players need to create a structure in a place where there is no local labor source or builder’s guild.

I call this bootstrapping. If the players are suddenly magically stranded like Robinson Crusoe, I shouldn’t be staring blankly at a ruleset that says “Start by hiring laborers at nearby towns.” or “I hope you have 20,000 gp of the local currency.” Those types of systems aren’t useful.


Players are annoyingly creative gits. The construction rules should be able to get a general cost hammered out quickly, and then add costs for adornments and extras after the fact. On top of that, the system should let the players create anything they can think of.


We want players to participate in this system, both by wanting to have buildings and actually building things. So the gameplay elements need to be rewarding, and it needs to feel good to assist in construction. Part of the scheme behind this needs to allow players to do things that makes Verisimilitude cringe. The system should reward player interaction, not punish it.

Also, being able to draw a little sketch of how the rooms in their base are laid out is always fun.


One of the problems of D&D Archeology is one of conversion. For instance, one of the rules from a 2e sourcebook (The Castle Guide) has magic items contributing to construction by giving a percentage of their XP value as days of construction. Now, I can guess at what that means, but to actually have something useful from it, I need to figure out where they keep that information in 2e, deciding what that means in 5e mechanics, come up with those numbers for each magic item in the party, and this is sounding like work just to type.

System agnostic encapsulation is what we’re looking for. I acknowledge that any system created to interact with 5e cannot be perfectly system agnostic, but the more we limit how the core system (5e) interacts with our new system, the easier it will be to move it to another game.

The New System

I could tell you about all the systems that didn’t work, but that seems counterproductive. So let’s just jump into the system that  does work.

At the core (like, 99%) of my system is this blog post by Chris Kutalik of the Hill Cantons, which I’ve mentioned before. This is such a simple concept, I’m not sure why I didn’t think of it before. I was even using a variation of it in my vehicle construction rules I was working on!

Basically, every structure is comprised of 10ish foot cubes. There is a table that lists building materials, how much a 10 ft cube costs, and how long it takes to make. Basic furnishings, like doors, tables, and so on, are included in the costs. A second table lists add-ons, in case a standard door wasn’t enough, you can upgrade it to a portcullis, a secret door, or whatever.

It’s a nifty system, meeting my criteria of Simple and Flexible. I think it may also meet the Portable criteria, as it’s a system designed for OSR that I’m converting to 5e with little thought. The big difference would be gold inflation, but I think it’s close enough. Converting to another genre would be as simple as changing the costs and maybe adding a few materials to the list.

This chart is set up to deal with a number of workers/days. The more workers you throw at a project, the faster it is built. If the party is just hiring the work, this is all you need.

Converting to Chunks

In my hexcrawl article, though, I mention that I use chunks instead of other times, a four hour block of time. Getting workers/chunks is simple, we just double it. Normally, workers would function for just eight hours or two chunks a day, but part of my Hexcrawl system is that players can push themselves, risking exhaustion for potential rewards. Like getting the walls or the roof up before stopping for the day. So if the player wants, they can work three chunks a day, and get things built sooner.

Well, done sooner in the amount of time taken. The number of workers/hours needed doesn’t change.

Player Characters as Construction Workers

To incentivize players to get their hands dirty, we’re going to make them really good at things. 2e’s The Castle Guide has some interesting rules for us to adapt. Straight out of the gate, instead of contributing a base 1 chuck of progress per chunk spent, PCs contribute progress equal to their level per chunk spent.

I’m sure it’s easy to see how a Fighter can do the work of 10 men, but how about the wizard? Well, the first thing is this is an Abstraction. The PCs are better solely because they’re the PCs and they don’t need a further reason. In the fiction, however, the Wizard is using small magic to assist in things, the monk is driving nails with a single finger, and the bard’s singing is making all the other workers more effective while mechanically, it’s him doing the work instead of them. You can describe how things work any which way.

On top of their default progress, D&D characters have a lot of things that they can do. Every ability, feature, or power, fits into one of three (or four) ranks of utility.

Utility Value Table

Level of utility
Not Useful This feature doesn’t help progress and shouldn’t be spent (Examples: Sneak attack, Divine Sense, Conjuration Savant) Value x 0
Somewhat Useful This feature can be argued to be helpful, but even on hearing the arguments, it still feels like a stretch. It’s not super clear how helpful the ability would be, but it is still somewhat helpful. (Examples: Danger Sense, Martial Arts, Favored Enemy(“We’re designing an anti-orc fort and they’re my favored enemy”) Value x 1/2
Useful It’s easy to agree how useful this ability would be in construction. (Examples: Jack of All Trades, Expertise) Value x 1`
Core function Feature is designed for construction of this sort. Very rare in 5e Value x 2

Most abilities that don’t cost resources don’t count towards progress. When you use a cantrip or a ritual spell, or have a useful class feature assist in construction, if it can be used at will then it’s just flavor. It’s part of your class’s level being added to the progress. However, some abilities are very suited towards Construction and grant an additional benefits (see tables at the end for specifics)

Magic items, however, provide a bonus to progress based on the item’s utility (see the table) and the item’s rarity even if no resources are consumed. Common items provide 1 point, Uncommon is 2 points, and so on until 5 points at legendary. This value is added to the chunk progress.

Building with Magic

Spells have their value modified by the Utility Value Table. Spells, including spells cast from items or racial features, have a value equal to the level they are cast at. If the spell doesn’t have a benefit of casting at a higher level, then using a higher level spell slot has no benefit.

The duration of spells doesn’t matter. It’s assumed you’re saving the magic for the most optimum moment. A spell that summons creatures does not increase the number of workers. Count it like any other spell.

Building with NPCs

In addition to the PCs working, you can have all sorts of NPCs working. Most simply provide 1 Progress per chunk, although some creatures might get some bonuses if the GM is feeling generous.

A potential factor in NPC progress is size. Structures have a size, indicating what size creature it is built for. Creatures 1 size larger than the structure gain +1 progress when building. Creatures 2 sizes larger gain +1 progress when building. Creatures 1 size smaller than the structure gain -1 progress, and a creature 2 sizes smaller gains -2 progress. A character who is 3 size categories different from the build can’t assist, as they are either too small to affect anything, or so big they risk breaking things with every touch. Creatures that would apply negative progress provide 0 instead.

For every 2 creatures that provide 0 progress, gain +1 Progress.

Most NPCs look for 5gp a day for their services, which is 2 chunks of work.

Build Checks

I’ve decided that most construction doesn’t need to have an ability check. As stupid as 5e’s crafting system is, you have to admit it doesn’t gatekeep behind skill gates (just impossible-for-standard-play money and time gates). Small structures are simple enough to do. Larger buildings get more complicated. Maybe it’s worth getting a Intelligence Check to determine if they can create the blueprints if it seems very unlikely. The Hill Canton system asks for architects and foremen, but their domain game is slightly different than what I’m looking for.

Other things

You do not need to have the full value of materials to begin, but only certain progress can be made without full supplies. Likewise, you don’t need to complete the build in one straight session.

Building A Ship

There is no way that WotC has built their ships as structures that work inside this system, but let’s look at it. The Keelboat is the right size of ship for a D&D party and not much more. The PHB lists its value at 3,000, for a vehicle that is 60 ft by 20 ft. Some simple math tells us we have 12 cubes. Wood costs 30 gold a cube and takes 32 days of work each. A second round of simple math gives us a material cost of 360 gp, and 384 days of work.

5e assumes that skilled workers cost 5gp to hire a day. Not all of the job requires skilled labor, but we’ll assume it averages out to that. A highly valuable shipwright makes more, apprentices make less, 5gp works well enough for the average. 1920 gp, then hires our workers. More math gives us a project summary of:

Materials       360 gp
Labor        1920 gp
Profit          720 gp

So 24% of the Galley’s cost for outright purchasing is markup.

Interaction with Hexcrawls

In addition to using my chunk notation for time, hexcrawls interact with construction in one crucial way and that is the idea of the Luxurious Rest. In an effort to balance the overland travel, the player’s clock has been elongated. They cannot take Long rests and short rests take 8 hours, unless they are at a place that qualifies for Luxurious Rest.

This keeps parties from being able to wander endlessly through the wilderness at effective full power, where casters can wreck faces in every single travel fight. It also threatens the front line, as their HP resources slowly decline. Overland travel becomes a resource management game, instead of a slog of too easy (and therefore superfluous) combats.

There are four factors to qualify for a Luxurious Rest

  • Sleep indoors, on a bed
  • Have a full bath (or option for it)
  • Eat off a table, with food cooked in something reasonably resembling a kitchen
  • Feel safe from external danger

A bedroom, a bathing room, and an eating area. A wall or a fence could be useful for feeling secure, or just being an area that’s been fairly explored and settled. Basically, you need to be in a town or a fortification that a lot of work has gone into if you want to have a peaceful rest. But it’s very subjective and dependent on the GM’s say so.


Racial Features

Race Feature Name
Any Powerful Build The character counts as one size larger when determining progress.
Any Sunlight Sensitivity When working in direct sunlight, -1 progress
Dwarf Stonecunning When working primarily with stone, +1 progress
Gnome (Rock) Tinker When working with gadgets and mechanisms, +1 progress
Hobgoblin Martial Advantage* When working with a crew of Hobgoblins, +1 progress
Human (Mark of Making) Artisan’s Intuition +1 progress
Lizardfolk Cunning Artisan When working primarily with bone, leather, or other materials taken from a creature, +1 progress
Loxodon Trunk +1 progress
Minotaur Labyrinthine Recall* When constructing a maze, +2 progress
Warforged Constructed Resilience Warforged automatically succeed on saves to continue strenuous labor. (They can work around the clock)

*Feature taken from monster stat block. Check with GM before including it in your math.

Class Features and Benefits

  • Artificers
    • Tool Expertise +1 Progress
    • Infusions might be argued for +1
    • Flash of Genius +1 Progress
    • Spell Storing Item: counts as casting the spell
    • Armorer Power Armor +1 Progress
    • Battle Smith Steel Defender counts as having an extra character
    • Artificers have a lot of complicated benefits as they level. Good luck
  • Barbarians
    • Rage: +1 Progress
    • Frenzy Barbarians get an additional +1 progress if they Frenzy
    • Level 6 Bear Totem barbarians get an additional +1 progress
  • Bards
    • Each use of Bardic Inspiration grant a different chacter +1 Progress
    • Jack of All Trades: +1 Progress
    • Eloquence: If Infectious Inspiration has a valid target, it can be used
    • Lore: Peerless skill you can use BI to give yourself +1 Progress
  • Cleric
    • Divine Intervention: DM’s discretion
    • Forge: Artisan’s Blessing +1 Progress
    • Knowledge: Knowledge of the Ages +1 Progress
    • Unity Emboldening Bond: If the 2 bonded characters are working on the same project, they may each add +1 Progress
  • Druid
    • Wildshape +1 Progress
    • Shepard: Spirit Totem +1 Progress
    • Wildfire: Summoning your wildfire +1 Progress
  • Fighter
    • Action Surge +1 Progress
    • Fighter (Champion) Remarkable Athlete  +1 Progress
    • Fighter (Rune knight)
      • Fire Rune +1 Progress
      • Invoke a Rune +1 Progress
      • Giant Might +1 Progress
      • Blessing of the All Father An ally gains +1 Progress when you use Giant Might
  • Monk
    • Unarmored Movement Improvement (Level 9) +1 Progress
  • Ranger
    • Natural Explorer +1 Progess if in favored terrain
    • Beastmaster: counts as having an extra character
  • Rogue
    • Reliable Talent +1 Progress
    • Thief Fast Hands +1 Progress
  • Sorcerer
    • Meta-magic Twin spell or Extended spell, treated like a second casting of the spell
  • Wizard
    • Wizard Spell Mastery ???
    • Divination Portent can be used for +1 Progress no matter the roll
    • Transmutation Minor Alchemy +1 Progress

Skilled Feat gives +1 Progress.


There’s a lot of work still, to go into figuring out how hexcrawls and related systems, work, but I think I’m making good strides. I have a lot of sources to look into and glean systems and tidbits from. but it feels like it’s moving forward, which is nice.

Obligatory Hey, I have a patreon, but who can afford that right now?

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