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RimWorld: Killbox & Defense Layout Encyclopedia

Every killbox design ranked: singularity, heat trap, funnel, and the new meta for each storyteller. Turret placement, cover mechanics, sapper-proofing, and mortar pits.

24 min read5,600 words2026-04-19
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RimWorld

On the rim, your colony lives or dies by its defenses. A single breach raid can end a 50-hour colony in minutes. This guide covers every killbox design, cover mechanics, sapper-proofing, turret placement, and storyteller-specific defense strategies for Cassandra, Phoebe, and Randy.

šŸŽÆ Cover Mechanics: The Math

RimWorld's combat is a dice roll. Cover reduces the attacker's hit chance. Stacking cover is multiplicative, not additive.

Cover TypeBlock %Best Use
Sandbags57%Colonist shooting position. Place in a line, colonists stand behind.
Barricade57%Same as sandbags but uses steel/stone. Indestructible vs fire.
Wall (corner peek)75%Best cover in the game. Colonist peeks around corner — 75% block.
Wall + Sandbag83%Wall corner + sandbag in adjacent tile. The meta: best possible cover.

The Wall-Sandbag Meta

Build pattern: Wall — Sandbag — Wall — Sandbag — Wall... Colonists stand behind the wall, peeking around the corner. The sandbag adjacent to the wall stacks cover multiplicatively. Total: 75% (wall) + 57% of remaining 25% (sandbag) = 83% effective cover. This is the highest achievable cover in RimWorld.

šŸ° Killbox Designs Ranked

S-Tier

Classic Singularity Killbox

A long 1-tile-wide tunnel ending in a large open room. Enemies enter single-file. Your 10 colonists stand at the far end, all shooting the entrance. No enemy can fire back until they exit the tunnel. Place sandbags at the tunnel exit so enemies can't stop to shoot. Turrets on side shelves for crossfire.

Best for: All storytellers, all raid types except breach/sapper.

S-Tier (Situational)

Heat Trap (Burn Box)

Enclosed room at the killbox entrance. Wooden floors + wooden barricades. When enemies enter, molotov the barricades. Room reaches 200°C+ in seconds. Everything inside dies — including loot. Stone doors to contain heat. Best on mountain maps with overhead roof.

Best for: Late-game tribal raids (50+ enemies). Insect infestations.

A-Tier

Funnel Killbox

Open field narrowed by walls into a V-shape. Enemies are forced into a kill zone 5-7 tiles wide. Colonists line up on the wide end. More forgiving than singularity — colonists can spread out, fewer friendly fire incidents.

Best for: Early-to-mid game. Colonies with 6-8 shooters.

B-Tier

Turret Hallway

A 2-tile-wide corridor with turrets every 3 tiles on both sides. Enemies walk through and get shredded by crossfire. Expensive in steel and components. Requires constant rearming.

Best for: Mid-game when steel is abundant. Combined with a singularity entrance.

🧱 Sapper-Proofing Your Base

Sapper raids ignore killboxes. They mine through walls and mountains to reach your bedrooms. Counter-strategies:

Double-Wall Outer Perimeter

Sappers target the shortest path to a bedroom. Double-thick granite walls everywhere except your killbox entrance. They'll choose the killbox as the shortest path.

Unpowered Turret Bait

Place an unpowered turret behind a single-thickness wall where sappers approach. They'll mine toward the turret — and walk right into your prepared defenders.

Interior Defensive Positions

Build mini-bunkers inside your base. A 3Ɨ3 room with sandbags, 2 doors, and a shelf of EMP grenades. If sappers breach, your colonists fall back to these positions.

šŸ¤– Turret Placement Guide

Turret TypeRangeDamageBest Placement
Mini-turret25.911/shotKillbox side shelves, 3 tiles apart. Provides covering fire while colonists shoot.
Autocannon32.925/shotBack line of killbox, behind colonists. Long range, high damage, slow fire rate.
Uranium Slug44.960/shotOutside base walls for centipedes. Extreme range, extreme damage, very slow fire.
Mortar50050 AoE4-6 mortars in a central cluster. EMP shells for mechs, HE for sieges, Incendiary for tribals.

FAQ

What's the minimum defense for my first year?+

A 7-tile-wide corridor ending in a 9Ɨ9 room. 3 sandbag positions for colonists. Wooden traps along the corridor floor. That's enough for the first 3-4 raids.

How do I deal with drop pod raids?+

Interior turrets in every room. Drop pods bypass outer walls. Keep a shelf with EMP grenades in your dining room. Draft all colonists IMMEDIATELY — don't wait for them to reach positions.

Randy Random sent 50 manhunting squirrels. Help?+

Block all doors with a drafted colonist standing in the doorway (hold door open). Squirrels can't break doors fast. Wait 24-48 hours until they fall asleep, then hunt them one by one. Or use a molotov.