RimWorld Never Build Floors Guide

by bbqftw

A brief introduction

Figured I would share some of the ‘unintended mechanics’ I and kakarotultrainstinct have learned over our time playing this game. From “mildly curious” to “turns merciless raids into basebuilder” to “useful information for ethical players” hopefully this series will have something for everyone.

In general, this information is drawn off play experience, or the play experience of others on Cass/merciless, almost exclusively in vanilla settings (I don’t believe things like Moody have hidden game mechanic altering features, at least..). So I believe this information should be pretty widely applicable.

So let’s start with “why I don’t build floors.”

Reason 1 – Never use a janitor again

One of the things that is drilled into a new players head is the underrated vitalness of a cleaner. What if I was to say that a janitor could be made, aside from the occasional drop pod raid, completely unnecessary?

Dirt is produced by going from an unfloored tile such as soil to a constructed tile.

Trash is produced while human pawn is walking on a constructed tile.

Animal filth is produced while animal pawn is walking on a constructed tile,.

Obvious solution is – don’t use constructed tile. Or, to put it in a more catchy way, dirt can’t get dirty.

Rough stone is a special tile in this regard. Not only can it not get dirt tracked onto it, it has a cleanliness value of 0.00, equivalent to most non-sterile tiled rooms. This should be distinguished from rough-hewn stone (which resides under mined out rocks), and smoothed stone, which can get dirt-tracked onto it. This makes rough stone an extremely valuable type of terrain. Its like a self cleaning concrete!!

Side note — you can access more rough stone by mining under resource veins. But again, regular rocks like slate/granite will give you disgusting rough-hewn stone instead.

Realizing that dirt production is proportional to unfloored tile -> constructed tile connections also explains why having a cleaner is also especially punishing for early game. Later in the game, most pawns in their daily work in floored bases are moving from constructed to constructed tile, and these movements don’t produce dirt. But early game, practically every movement involved in collecting resources involves a movement from outside (unfloored) to constructed tile, resulting in dirt. Thus, in general, the percent of total available labor dedicated to cleaning floored bases is much higher in early vs. late game.

Cleaning in vanilla is also painfully inefficient since it relies on home area, so you run into either issues with firefighting or designating sane cleaning zones. Good thing we don’t actually need to do it, with this knowledge!

Reason 2 – Never have kitchen food poisoning problems again

So you might be wondering, what about food poisoning? Surely you don’t want to cook on a dirt floor! Well, you could use the previous information, and only put your kitchen in rough stone. But it turns out you don’t even need to do that.

Here are the relevant code in the defines that governs a room’s food poisoning contribution (to see a it ingame, you can also turn on advanced room stat view in dev mode): https://i.imgur.com/u1QDQaa.png

Essentially, at –5 cleanliness, there is 5% food poisoning chance, which linearly goes to 0% at… -2 cleanliness. What’s the cleanliness of a dirt floor?

-1. And remember, since trash doesn’t appear on it, nor dirt be tracked onto it, you can maintain this -1 cleanliness without a cleaner – unlike a floored kitchen, where if there is unfloored tile anywhere close, there’s the chance of tracking dirt in. And since often people use rather small kitchens, a single dirt track massively impacts the rooms cleanliness.

Knowing that the threshold for food posioning is -2 cleanliness also allows things like moving the kitchen to the main production room, as a large room dilutes any cleanliness hits to the overall rating, thus you have an extremely large buffer to work with.

Reason 2A — no more trying to manually force your pawn to clean the doorway

Seriously this was one of the most annoying things of having floors I am glad I never have to do this again

Reason 3 – Get the max return for your wealth, and a concise practical bedroom/barracks guide

One oft stated reason to floor your rooms is beauty improvement over the base -1 of soil and rough stone. But how efficient is it, really? Remember that expectations is a thing — as your total wealth grows, your pawns also suffer effective mood penalties that are global and unconditional. So overinvesting wealth to achieve low mood gains from impressive rooms actually has a significant drawback (this is why I view tutorials such as Yeti’s bedroom guide not so much wrong as useless, as they do not factor in practical play considerations such as this).

So lets look at the beauty / wealth ratio of tiling:

Wood floor 3.9 / tile (net beauty difference of +1/tile) — 3.9$/beauty

Stone floor 7.6 / tile (net +2 beauty/tile) — 3.8$/beauty

Carpet 13.4 / tile (for net +3 beauty/tile) — 4.4$/beauty

Compare, for example, some representative large sculptures:

Wood normal — 1.95$/beauty, 100 beauty/tile. excellent — 0.98$/beauty 300 beauty/tile

Marble normal — 1.59$/beauty, excellent — 0.78$/beauty

Steel normal — 3$/beauty, excellent — 1.5$/beauty

Of course, floors may also increase cleanliness (if you didn’t use a rough stone room), and also don’t count against your space rating. But this effect is very small — a single excellent sculpture is going to contribute around ~10x the beauty of an entirely stone tiled 15-tile room. The difference is clear I hope, even with wood / marble-poor biomes. The efficiency gets higher as your artist improves, and for the true min-maxer, sculptures can trivially be punched to 10% of their market value (50% of their HP), increasing their relative efficiency 10x.

The TL;DR —


  • Can track dirt, requires janitorial maintenance
  • Poor beauty/space efficiency
  • Poor wealth/beauty efficiency
  • Can’t be punched
  • Can’t be moved conveniently


  • Can’t track dirt
  • Insane beauty/space efficiency
  • Good beauty/wealth efficiency
  • Can be punched to lower total wealth, making insane beauty/wealth efficiency
  • Portable

Let’s look at some basic early game to midgame bedrooms, and how to make them workable floorless.

One of the classic bedroom setup I was taught (ty themelnteam) when starting the game was the 6×2 + wood floor + bed = dull, which for all wooded biomes is quite attainable. So this is a good start for iterating.

A nice rule of thumb, crediting /u/kakarotultrainstinct, is that (space rating x 4) is a soft cap for your impressiveness, with gains above this being achieved at rather high cost. Since this room has 15 space rating, or 14 with a statue, our reasonable cap for this type of room is the slightly impressive range (+3). Using this we can estimate the room sizes needed to hit a certain impressiveness with 1-2 statues (it should be noted that due to the space consumption of dresser, adding those things is often useless or even counterproductive — statues have something like 40x the beauty/space ratio. Please don’t put dressers in your bedrooms!!). For floorless rooms — 10 tile is the minimum to feasibly achieve slightly impressive, 14-15 tiles for somewhat impressive (+4), 22 tiles for very impressive (+5). Going higher is pretty impractical for bedrooms, from both wealth and defense concerns, since space efficiency aids sapper defense pretty significantly.

Incidentally, bedrolls don’t consume space rating, while beds do. Thus for situations where rest efficiency is not important, but room impressiveness is (like prison), it is superior to use bedrolls.

For early game considerations, the most important thing to do is avoiding the awful bedroom penalty. Going from awful -> dull represents 4 mood for a ~14 impressiveness difference. Going from dull -> decent is a 2 mood swing for ~20 impressiveness difference.

So how do we avoid awful bedroom on day 1 with a 6×2 bedroom + bed? 2 tiles of daylilys are enough to do thishttps://i.imgur.com/8uGrFqr.png . Of course this is a significant labor investment, but keep in mind you don’t have to clean this room unless someone bleeds on it, and planting random stuff gives actually gives growing xp, while cleaning doesn’t affect any skill.

If we elect to build on rough stone (which also cannot get dirt tracked onto it, but has a 0.00 cleanliness rating just like tiled floors), then we run into a slight issue, as you cannot plant on stone tiles. Plant pot + daylily can be used. Curiously, with this approach, a smaller bedroom is actually better, since a large room dilutes the beauty impact on the room rating.

So a 10-tile roughstone room achieves dull with single plant pothttps://i.imgur.com/i0DV6Ki.png .

You can go even smaller, up to 6-tiles with a single plant pot: https://i.imgur.com/oemBvVm.png (cramped interior doesn’t matter since mood is frozen while sleeping, so the negative moodlet doesn’t have time to actually affect the pawns mood).

Obviously the potential for room improvement is not very much with such space, but this is an early game measure anyways, so you can change up the bedrooms later. If you want to use 12 tiles w/ rough stone, you have to use 2 plant pots.

I warn you that making bedrooms to fully utilize rough stone is not very OCD-safe, as you end up doing stuff like this: https://i.imgur.com/5xKaM3s.png

For extreme desert enthusiasts (where you might have to use non-plantable floor that isn’t rough stone, 12 tile + 2 plant pots gives you dull): https://i.imgur.com/yQqFaWz.png

Moving into midgame, a single 200 beauty statue (good quality on any non-beauty bonused material such as wood or steel) gets you to slightly impressive range on a 6×2 soil floorless: https://i.imgur.com/PBrR9CI.png . If you floored this room with stone tile, you’d get 6 more impressiveness, not enough to bump you up a tier. This sculpture’s beauty impact is almost 10x that of tiling, and this is such a mediocre quality statue, as your artists progress the disparity gets higher and higher.

This is why I hate on minstrels far less than this sub (for the starts with multiple people), as art represents an extremely efficient means to stabilize mood.

You can utilize this same approach with barracks. You will eat the disturbed sleep penalty most of the time, but by starting with a barracks, all your investments in the barracks quality also will simultaneously benefit your dining and rec room bonuses. So the mood efficiency is pretty comparable to bedrooms early game. Here’s something that hits somewhat impressive — 21 flowers + 50 tile room: https://i.imgur.com/OwABBqF.png

(For some reason, unlike bedroom mood impressiveness thresholds, the barracks one is nonlinear — going from somewhat to very impressive represents a 2 mood swing, but the rest of the jumps are 1 mood each.)

If you go even more crazy on the flowers (70 tile room / 35 daylilies with random stuff you would put in a production / barracks / rec / dining combination room) you can even hit +1 mood barracks with +5/+5 dining / rec bonuses and +10 beautiful environment modifier for indoor workers: https://i.imgur.com/v84mPV9.png . Not bad for stuff you can scrounge up with practically zero research or skill investment! Remember, this kitchen is 100% health inspector approved, too — cooking on dirt is actually 100% safe! Though you probably want a plants passion guy if you’re going to go this route.

Reason 4 – Facilitates keeping animals in your base perimeter

Since animal filth is only produced in constructed tile, there is now no reason to exclude your grazers from being inside your perimeter walls. Not only is this cute, but animals represent some of the most effective means to combat drop pod raids as well as infestations (later installments will show ways to make combat animals even more effective without using the clunky release mechanic), so it is useful to have them able to rapidly react to center drops (which are the most likely to cause annoying property damage).

Afterword — things that floors actually do help

I would say that there is one non-trivial thing that floors do help with. Sterile floor infection chance is significantly better — 32% infection multiplier on a fully sterile tile room vs. 50% infection multiplier on a rough stone room is significant. So if you’re taking enough hits that this is a problem, you can consider this.

Other effects, such a surgery chance (which is now capped at 98%, pretty attainable with rough stone hospital) and research speed, I don’t really consider that significant.

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