01 — Building

Last updated: May 18, 2026 Patch context: post-April 30, 2026 mortar update (workbench upgrades, HE/frag rounds)

Building is the single most important system in Rust. Everything else — power, industrial, plants, scrap stockpiles — sits inside walls you built. A base that lets the wrong wall face outward, that puts the TC where it can be raided cheap, or that skipped the honeycomb is going to get raided no matter how good your gunplay is. This file is the math.

The four building tiers

You upgrade walls (and floors, doors, foundations, roofs) through four tiers using the building plan or the hammer's upgrade menu. Each step up multiplies HP and material cost.

Twig has no place in a real base. It exists for placement preview and for sneaky bridges/floors. Wood is wipe-day starter only — falls to a single satchel. Stone is the actual baseline for any base meant to survive past hour two. Sheet metal is where most solo/duo bases settle for the wipe. Armored is HQM-gated and most bases reserve it for the TC core and bunker walls only because 25 HQM per wall adds up fast.

Soft side vs. hard side — the most important rule in the game

When you place a wall, one side has visible brick/metal pattern (the hard side, outward-facing by default in single placement) and the other side has the wooden frame showing (the soft side, inward-facing). Soft side takes 2x damage from all explosives. This is the single biggest reason raiders pick certain walls to blow.

Rule one: every external wall faces hard side out. Always. If you have a wall placed wrong, sledgehammer it and replace it before you log off. A backward wall is an invitation — raiders ladder, see the soft side, and spend half the explosives.

Rule two: this is why honeycomb matters. Honeycomb is a second layer of walls behind your external walls, creating triangle pockets. The interior walls of those pockets have their soft side facing where a raider would emerge after breaking the outer wall — meaning the second wall in resists from the hard side because of how triangle geometry forces orientation. Good honeycomb means the raider keeps facing hard sides over and over.

Honeycombing

Honeycomb is the difference between "lost the wipe" and "they bounced off." The core idea: you don't just put one wall between your loot and the outside. You put a wall, a useless triangle of space, then another wall, then more triangles, then the loot.

A bare 2x2 stone base has roughly 4 external walls. To breach it costs ~5,600 sulfur (4 walls × ~1,400). A 2x2 with one honeycomb layer in stone has ~12 walls between any loot and the outside, costs ~9,000–12,000 stone to build, and forces raiders to spend 11,200–16,800 sulfur to reach any loot room. That ratio — defender pays 12k stone, raider pays 12k+ sulfur — is the most efficient cost-per-defense in the game.

Two-layer honeycomb (you'll see this on serious clan bases) doubles the raid cost again but quadruples your stone cost. Sweet spot for solo/duo is one full layer. Skip honeycomb on roofs above sealed core rooms only — anything that touches the outside gets the layer.

The Tool Cupboard (TC) — non-negotiable rules

The TC anchors your base. Without one, anyone can build over your foundation. With it, you have authorization to repair, build, and most importantly your walls have decay protection from the materials stored inside.

• The TC has a 40-meter no-build radius. Once placed, no one can put a new TC inside that bubble. This is your no-build defense — players can't twig-ladder up to your roof and place a competing TC.
• The TC must be fed materials to prevent decay. Walls decay roughly 24 hours after the TC empties out. Keep 1k+ wood, 5k+ stone, 500+ frags, 100+ HQM in there minimum during a wipe.
• The TC has only 24 inventory slots. Don't use it as your main storage — use it for upkeep materials only.
• Hide your TC. It's the raid target. Put it in a sealed core, behind 2+ walls of armor, with a code lock and a key lock as a double layer. If raiders can't find it or can't reach it in their explosive budget, they bounce.
• Common mistake: people put the TC in the first room they enter. Raid that wall, you're authorized. Push it deep.

Foundations, floors, roofs, and frames

Foundations cost the same as walls per tier but have higher HP (twice). They can't be replaced once placed without sledge — but sledge takes 10 minutes per soak. The first 10 minutes of placement is the decay timer for replacement, during which you (or anyone, if no TC) can pick the foundation up free.

Floors above ground level are walls' weak cousins — same HP as walls, but raiders can shoot from below. Always seal the bottom of bunkers (no triangle floors you can shoot up into the base from outside). Embrasures placed in floor pieces let you shoot down without exposing your head.

Roofs come in two shapes: full roof piece (square) and roof triangle. Roof triangles are sometimes used in 2x2 designs to allow water collectors on the top edge. Sloped roofs prevent rooftop camping but waste material.

Frames are wall variants with cutouts: doorways, windows, embrasures, garage door frames. Use embrasures inside core walls for shooting through during raid defense — they let you shoot out but not be shot at except through the slit. Garage doorways take garage doors (highest HP door: 600 HP, takes 3 C4 to break).

Doors

Common mistake: putting a wood door anywhere in your live base past hour 2. Wood doors are softer than wood walls in raid math.

Pro tip: code locks are 1 frag and instant. Key locks are 15 wood. Use code locks for main doors, key locks as a second layer on the TC door so a teamie who isn't trusted with full base access can still get to the TC for upkeep.

Window frames, embrasures, shooting floors

A window frame with no shutter is a hole. A window frame with iron shutters costs more but can be opened/closed with E. A wall with embrasure cutouts (the slit kind) lets you shoot through it without being shot back except by a perfectly aimed return — same applies to floor embrasures looking down.

For raid defense, you want:

• 2–3 embrasure slits looking at every external doorway
• 1 floor embrasure looking down at the front door (you sit above, raider plants C4, you push them off the C4 with bullets)
• Window shutters on every cosmetic window (close them before logout)

The April 30, 2026 mortar patch — building implications

The mortar update added a deployable Workbench-2-tier weapon that fires HE and frag rounds over long range. The standard mortar damages structures. Effects on building:

• 2x2 and 1x1 bases are largely safe. Mortars are inefficient against small footprints — the cost per wall via mortar is higher than C4. Solo bases keep their meta.
• Clan compounds got hit hard. Wide exterior walls and large compounds now eat HE mortar rounds from outside the wall range. Compounds need overhead cover (roof spam) and external walls pushed further from the actual base.
• Aim is purely trial-and-error. No reticle, no trajectory arc. This means a raider needs a spotter and time — which means mortars at night against a base with auto-turrets are still suicide. Daytime, undefended, far compound walls are the target profile.
• Workbench 2 has nine new upgrade modules. These are not craftable, only found. Build a WB2 minimum for any base that wants to research mid-tier components, but don't expect to easily upgrade it.

The full April patch notes are in 11_Patch_Meta_2026.md.

Decay

Walls and structures lose HP slowly when not under TC authorization or when the TC is empty. Decay rates per hour:

• Twig: instantaneous (no TC needed, decays in minutes)
• Wood: 5 HP/hour outdoors
• Stone: 5 HP/hour outdoors, 0 indoors
• Sheet metal: 3 HP/hour outdoors, 0 indoors
• Armored: 1 HP/hour outdoors, 0 indoors

Indoors means under a sealed roof. Outdoors means exposed sky. Decay is paused entirely when the TC has materials of the wall's tier inside. If your TC has 0 stone but 5k wood and your walls are stone, stone walls decay until you put stone in the TC.

Pro tip: sloped roofs and decorative structures decay even with a full TC if the TC is more than ~40 meters away. Multi-building compounds need a TC per building or extra TCs in outbuildings.

Floor stacks, jump-down boxes, foundation steps

A floor stack is two floors placed one above the other with a wall between them, used as a defensive layer. A jump-down box is a 1x1 box with a foundation removed so you can drop down a story — common in solo base designs because the jump-down is one-way, breaking pursuit.

Foundation steps (offset foundations placed at slightly different heights) confuse external builders trying to attach. They also slow ladder placement, which buys you a couple seconds during raid response. Worth doing on the perimeter foundation row.

Common base-building mistakes

1. Hard side facing in. Every external wall, every time. Hammer-and-rotate any wall placed wrong.
2. TC near front door. Push it deep. If the TC dies, the wipe dies.
3. Wood doors past hour 2. Upgrade to sheet metal the moment you have 25 frags.
4. Skipping honeycomb. Always at least one layer in stone or better.
5. Empty TC at logout. Stack it before you log. Decay over a 12-hour sleep is recoverable on stone, painful on armored.
6. No window shutters. Open frames let a raider plant C4 on the inside soft side from outside the base.
7. Single layer over loot. Always two walls minimum between any loot room and the outside.

Quick raid-cost reference

Soft side, single wall:

• Stone wall: 4 satchels (~1,200 sulfur) or 1 C4 (~2,200 sulfur)
• Sheet metal wall: 2 C4 (~4,400 sulfur) or 4 rockets (~5,600 sulfur)
• Armored wall: 4 rockets soft (~5,600 sulfur) or 8 rockets hard (~11,200 sulfur)
• Sheet metal door: 1 C4 (~2,200 sulfur). Full breach takes 1 C4 because door HP is 250 vs C4 550 soft damage.
• Garage door: 3 C4 (~6,600 sulfur)
• Armored door: 2 C4 (~4,400 sulfur)

Full table by item is in 10_Cheatsheets.md. The general rule: soft-side stone with one honeycomb costs raiders about 8–12k sulfur per breach attempt, which is roughly 30+ minutes of dedicated farming at scrap-tier and far more than most raiders will spend on a solo base.

What "good enough" looks like for a solo

• 2x2 stone base with full single-layer honeycomb (~12k stone)
• Sheet metal door on main entrance
• Hidden TC behind armored wall and second armored door (~50 HQM upgrade)
• 1 auto-turret (covered in 06_Automation_Circuits.md) with shotgun trap backup
• Window shutters closed at logout
• Stack the TC: 2k wood, 8k stone, 500 frags, 100 HQM minimum

That base costs you about 1 hour of farming and survives an offline raid for 12k+ sulfur of explosives. Most raiders won't pay that for a solo.