[ROUGH TRANSCRIPT from the video is below. This may contain many typos and errors.]


Burn Killbox

Hey everyone, Adam here with another Rimworld guide. This guide is part of a series regarding different defensive options in RimWorld.

Using killboxes has always been a hot button topic in RimWorld. Some are against the very idea and some love trying to optimize them. I stand by the stance of, do whatever is fun for you. I’ve played and had fun with and without killboxes.

So, in this rimworld guide to defense , I’m going to be talking about a setup I have used off and on for years and years. The burn box.

I’ll tell you how to build it, the optimal size, what it is good against, what it is bad against, and answer dozens of common questions I’ve been asked over the years. 

What is a burn box (Show it in action during this part)

A burn box is simply a room, hallway, or a series of those in which you super-heat the air in order to kill flesh-based enemies with minimal effort. 

So, how do you build it?

One great thing about the overall design is that it doesn’t have to be super precise. In the early game you can make it much smaller and then expand later. Also, connecting this to another kill area can allow you to go even smaller. If you want a minimum size that works for all applicable enemy types, though, you’ll need to start with at least a 19 x 19 outer wall.

A quick note, I do recommend you build it in this order to prevent long pathing issues later.

Build the 19×19 exterior wall. Leaving a spot at each end for doors.

Double up the walls. This helps hold in heat as well as safeguards from any one-off wall getting destroyed by an explosion or such.

Double-up the doors, also.

Now plan out your corridors, leaving space for around 30 tiles at the end.

Now place a piece of fence, made out of a material that will not burn, on every other tile starting at the enemy-entrance door.

Now go to the Architect button, zone, build roof area, and build a roof over the entire thing.

Now fill in all the walls, making sure to leave access for your workers without them having to walk through the maze.

You may be asking yourself why not use doors in the middle. I will answer that and a ton of other FAQ questions in a moment.

Now, make sure if this is connected to your base that you have at least a small unroofed, room area right outside. If not then you will super-heat the connected rooms and KILL YOUR OWN PEOPLE…not that I’ve ever done that… If this connects to an outdoors killbox then you don’t have to worry about that at all.

If you don’t want to have to remember the dimensions, feel free to head over to my website, adamvseverything.com, and download the blueprint for your game!

Now that your basic setup is done, we need fuel. I have tested just about every fuel imaginable, and will list the pros and cons of each later, but for now we’re going to use wood. It ends up being the best in most situations anyway.

Here’s the thing about wood, though, a single piece of wood has the same HP as a stack of 75. That means it burns the same length and heat regardless if you have a single piece or 75. But, without a mod you can’t specify a zone to have only 1 piece of wood. But there is a solution.

Turn off construction on all of your people by going to the work tab, then holding shift and right clicking on construct.

Now click to build wooden fences in all of the fuel spots.

Once the wood is delivered, select all the fencing and hit cancel. This will drop single pieces on the ground which you can no disallow.

This works better than actually building the fence and destroying.

This is also extremely low wealth. It’s like one tree worth of wood.

I also recommend putting a shelf nearby with wood on it for further refueling as needed.

The last step I recommend is causing collision. I won’t go over the entire mechanics here as I already have a guide on it – go check out my PATHING guide if you need to know the specifics.

We’re going to cause collision by putting a small room at the entrance with 1 door and an unpowered turret.

Now we just sit back and wait for a non-breach, non-mech raid to attack.

When we get the alert we just head over, grab the nearby shelved molatov, and have the pawn throw a few bottles on the wood.

Within seconds the room is approaching 1,000º celcius. The raiders fall over, the fire self-perpetuating and cleaning most of the mess up as well!

That is it, the extreme basics. Get a long tunnel with a room for fuel that burns for a long time. Light it with something. Go back to work.

However, there are tons of additional things to keep in mind, caveats to things, situational changes, etc. I am going to go over these in a sort of rapid-fire section in order to keep the guide relatively short.

Does this kill the BIGGEST possible raids? – Yes. Even quest raids with 700+ tribals or 300 pirates etc.

Does it work against tribals? – yes, even jogger impids

Does it work against pirates? – yes, even go-juice pigs and wasters

Does it work against the empire? – yep

What about firefoam popper raiders? – The foam triggers on damage taken, they die before they get to the actual fire area.

Does it work against animals? – Yes, however animals that are stopped by fencing will get stuck and destroy some of the fence. You can use chunks or sandbags instead if you want, though they are way more costly and increase wealth. And no, sandbags do not burn. Also, barricades stop fence-blocked animals just like fences do.

Does it work against insects? – Yes, but you need something continuously damaging an insect or a hive so they don’t yo-yo back home.

Does it work against someone in phoenix armor with heat resist genes and a comfortable tmperrature over 500º? – Yes. The game can’t spawn anyone that can survive unless you are using mods.

Does it work against sappers or breachers. – Short answer is no, though there is an exploit that makes it work.

How much wood do I need? – The more flames the faster the heat-up time. I like to go with 30 or more.

What other material works as well? – You can actually use crap that other raids have dropped such as tainted clothing, old bows, etc. You may need more room though as some of these may already have reduced HP. Wood is still preferred, unless you are on a playthrough in which it is scarce.

What all can you start the fire with? – Molatov, which you can craft at a machining table, buy, or get from a raider, incendiary launcher, flame bow, or even friendly mechs. Anything that can spark a flame without causing an explosion.

Can I use IEDs to self-light? – Yes, but I don’t like to. For one, that means it will trigger even if you don’t want it to. So if a mech goes through the tunnel, bam, you have to reset everything even though they are immune. Sometimes I want to actually kill the tribals for some .. uhh .. humane leather exports. Also, putting the fuel in the early part or the middle can cause problems.

Do you need double walls? – I highly recommend it as it insulates the room. Also if a single wall gets destroyed it won’t suddenly reduce the temp.

Do I need to shut the doors behind the raiders? – No, it gets hot enough even with the doors being open because it is still considered a room. It’s too hot for the heat to escape quickly enough.

Does this work in super cold maps? – Yes, even on ice sheet with a cold snap. Just make sure the walls and doors aren’t made of flammable material and that you don’t start the fire too early.

Can I use vents? – Not really, they catch on fire and can also be destroyed by the pathing raiders.

Can you use geothermal? – Not really, it doesn’t get very hot especially with the doors open. Heaters don’t work either and would be a ton of wealth and susceptible to power issues etc.

Should I put access doors in? – If you do raiders will destroy them quickly when they start to break. Meaning you have to rebuild.

What about prisoners? – Another great thing about this box is that it can give TONS of downed enemies very easily. I won’t get into the details, but, basically the more pawns you have the less likely it is a raider will survive when downed. Heat stroke ignores this. Once enemies are downed you can deconstruct a wall to INSTANTLY stabilize the temperature since it is no longer considered a room.

Can this be used in a mountain base? – Yes, but be careful, you need an unroofed room area between it and your rooms so you don’t cook yourself. Also breachers are going to destroy it on the way in over and over.

Can friendly mechs go inside? – Yes, they are immune to the heat. You can use them to repair or such even when it is still hot.

What stage of the game can or should you make this? – As early as you can get something to light the wood on fire.

Is rotstink or pollution an issue? – No, it’s pretty much self-cleaning. Though corpses will get pushed through the wall sometimes.

Will it kill vampires? – The heat can’t, but if they catch on fire they will die.

Does burning a child raider alive give the same debuff as shooting one? – Nope. Colonists get sad shooting, uhh, young raiders but not burning them alive apparently.


Now I will go over some alternatives to wood.

Clothing/etc works as mentioned earlier, just may need more of it

Steel conduit works super well. Recommended to use if you have a lot of steel but no or little wood, like in the desert.

Don’t use built fences, they have too low of HP.

Straw floor works, but means you have to grow hay

Wood floor works but takes way more wood and time, plus gives more wealth

Barricades – wood works but again is nto worth it. Steel barricades don’t ignite fast enough.

With the tunneler ideology you can plant nutrifungus. The downside is having to replant as well as it dying if it gets too cold.


Now for some crazy, bonus stuff.

What if you don’t have any material at all to burn? What if another huge raid spawned and you didn’t have time to set this back up?

Well, it turns out you can sometimes just attack the floor.

You can simply put a targetable spot such as a baby sleeping spot or animal spot down and have 1 person with a bow, or 2-3 people with incendiaries or molotovs attack the area. You can even have 2 or more scorcher mechs do this for you. The only downside is that it is more hands-on.

Speaking of crazy, though, during my testing I found that a single pawn with a flame bow and bandolier actually made the box get hotter faster than the wood and Molotov method!

Check out my super short guide about the flame bow burn setup. The link is in the description and pinned comment. 


And I think that does it. You have now been imparted with the knowledge of The Burn Box. Whether you want to utilize this so your colonists can go back to researching as the human popcorn goes off in the background or not is up to you!

Be sure to Keep an eye out for more upcoming defense guides on my channel. 

If you enjoyed this Rimworld Killbox and defense guide or it helped you at all please consider subscribing to the channel, liking the video, leaving a comment down below, and sharing it with others. If you’d like to reference a written version of this guide be sure to head over to my website at adamvseverything.com/guides.

You can also download the blueprint for the setup at adamvseverything.com/downloads


And, as always, thanks for watching!

Developer(s) Ludeon Studios
Publisher(s) Ludeon Studios
Designer(s) Tynan Sylvester[1]
Tynan Sylvester
Piotr Walczak
Ben Rog-Wilhem
Rho Watson
Ricardo Tomé
Composer(s) Alistair Lindsay[2]
Engine Unity
Platform(s) Microsoft Windows, macOS, Linux
Release October 17, 2018
Genre(s) Construction and management simulation
Mode(s) Single-player

Subscribe to MY Newsletter

Want to know as soon as a new guide or playlist is posted? Sign up for my email newsletter and receive a notification straight to your inbox when I release new content. Your email address will never be shared.

No spam ever, Just awesome content. What are you waiting for?