I've completely rebuilt my base in a Forest Biome from the ground up since the release of the 1.2 update. And when my base was the same as in my old world, and most of the npc's were there (except the hardmode npc's), I thought it was time to activate hardmode.

The first thing I noticed is that I couldn't place any of the new npc's in my house because it was corrupt. Apperently this was because the crimson was under my house going from top to down. So I needed to move my house to another Forest Biome. But the Crimson is spreading really fast!

But how long will it take before the Crimson will have corrupted every green bit of my world? Or should I just place a block of stone to stop it? Is there even a way to stop it? I could always build it in the ice biome. But I find the constant visible falling snow annyoing. I already tried the obvious: purification powder. But the Crimson is just keep coming back!

What would you do?


Once I've made a new world, this time in a floating island (so no form of biomes will reach it), and was transfering some of my items (including NPC room furniture), I saw what was wrong all this time: I forgot to place a few walls! I don't know if this was causing the This house is invalid error. But at least this was a possible reason.

Thanks for all the suggestions and sorry for wasting your time. Have an Ale on me!

  • Have you already activated Hardmode? Or are you dealing with pre-hardmode corruption?
    – Zibbobz
    Commented Oct 10, 2013 at 14:05
  • 1
    I did what I always do at every "game changing" update: built a house for npc's, dig straight down to hell, slaughter the WOF, and explore the new stuff in the update. I build the house next to an Ice Biome, which was next to the Crimson. The Crimson apparently went straight through the Ice Biome to the Forest Biome!
    – VascovdEng
    Commented Oct 10, 2013 at 14:12
  • 4
    Well, for one, I'd suggest NOT defeating WOF right away! A lot of the changes that were made have been made to the pre-hardmode world. By defeating WOF, you risk your new biomes being run over by corruption and hallow before you truly get to experience any of it! You may even want to start with a brand new character on a brand new world.
    – Zibbobz
    Commented Oct 10, 2013 at 14:16
  • 1
    I'd highly recommend @Zibbobz's suggestion. You're going to miss out on a lot if you use an existing character.
    – SaintWacko
    Commented Oct 10, 2013 at 14:23
  • Also, gaming.stackexchange.com/questions/41839/…
    – user9983
    Commented Oct 10, 2013 at 14:35

2 Answers 2


Crimson and Hallow will spread through your world like wildfire, underground and all through your map, including snow biomes.

Your best bet is to pick up as much of the unique biomes as you can to store in your pocket, and start building preservation biomes in the sky, preferably above Hallow to avoid having your preserves corrupted. This will run the risk of having frequent Wyvern attacks but... well, that's the risk you run when you go into Hardmode.

My real suggetion to you though is to start over on a new world, maybe even with a new, ungeared character, and NOT go directly for Hardmode right off the bat. With all the changes that have been made to the pre-hardmode world, it's worth exploring before taking on the WOF.

  • Crimson should take over the snow biome. There are at least 'Red Ice Blocks' that are Crimsonified Ice.
    – Reafexus
    Commented Oct 10, 2013 at 14:50
  • I've heard that these are actually pre-generated and do not spread, but I cannot confirm or deny this.
    – Zibbobz
    Commented Oct 10, 2013 at 14:52
  • There's also purple for Corruption and Pink for Hallow. Commented Oct 10, 2013 at 15:09
  • @Domenik VanBuskirk Spread from corruption/hallow, or pre-generated? Also, pre-Hardmode or Hardmode?
    – Zibbobz
    Commented Oct 10, 2013 at 15:22
  • Pre-hardmode, it can happen. If a Hallow/Crimson/Corruption biome is near an ice biome, you will get colored ice. I'm not 100% sure if it spreads through ice. Easy way to test would be to put regular ice near colored ice and see what happens. Commented Oct 11, 2013 at 14:31

The Clentaminator, along with Green Solution can be used to purify it. However, these are sold by the Steampunker, who only appears in hardmode (the condition for selling individual solutions varies; the Green Solution only appears when no other solution is being sold).

You have other options. Firstly, you can build upward. The corruption rating of a home counts all corrupted tiles in a 45-tile radius. Moving upwards dramatically reduces the odds of that being an issue. If you go up high enough you will be outside of the Biome. There's no need to worry about making your homes accessible from the land; if someone moves in you can just save + quit and reload and they'll be in the home.

Secondly, activating hard mode of course spawns Hallowed and Corruption (or Crimson, in your case). Hallowed does not prevent homes from being suitable, fwiw, so if you can build that way you will also be safe.

  • 1
    Crimson and Corruption cannot exist in the same world with the player manually adding one or the other. If your world contains crimson in it, then instead of hallow/corruption spreading through the world after beating the WoF, it'll be hallow/crimson. Commented Oct 10, 2013 at 15:12
  • 1
    I am aware that crimson and corruption cannot exist in the same world.
    – peacedog
    Commented Oct 10, 2013 at 15:31
  • Red solution creates crimson, green solution purifies it.
    – 3ventic
    Commented Oct 10, 2013 at 15:42
  • 1
    The Clentaminator is a long range purification powder. The Crimson will spread either way.
    – VascovdEng
    Commented Oct 10, 2013 at 17:23
  • 1
    Yes, and once you purify you can excavate a wide enough space to halt the natural spread. On the Corruption side (and presumably the Crimson though I haven't seen it in Hardmote yet), certain enemies can still spread the biome via projectiles. But you can proof against that if you are feeling industrious.
    – peacedog
    Commented Oct 10, 2013 at 17:49

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