Your base rots because the Tool Cupboard bills a share of every block's build cost each 24 hours, and once a material runs out, every piece made of it loses health on a fixed timer. The share depends on how many blocks the TC covers, from 10% on a starter hut to a third on a clan compound, and since September 2026 on how many players are on the base too. Here is what the TC is charging, using the calculator's numbers, and the cheapest ways to stop logging in to a half-decayed shell.

What the Tool Cupboard actually charges

Upkeep is a cut of build cost, not rent. Every 24 hours the TC takes a percentage of what each building block under its privilege cost to build or upgrade, paid in the same material: wood, stone, metal fragments for sheet metal, high quality metal (HQM) for armored. Doors and window pieces are billed as well. Boxes, furnaces, turrets and sleeping bags are not.

Each material is a separate bill, shown in the TC as a cost per 24 hours. An all-stone base with sheet metal doors needs only stone and frags, and if the frags run out the doors decay while the stone walls carry on untouched. The percentage is one blended rate worked out from the block count and applied to every piece's build cost, rounded up.

The four brackets

The rate climbs in four server-defined brackets: the first 15 blocks at 10% of build cost per day, the next 50 (blocks 16 to 65) at 15%, the next 125 (66 to 190) at 20%, and everything past 190 at 33.3%. The TC averages those across the whole structure, so a 20-block build pays 11.3% on every piece.

That average is why big bases hurt. In the upkeep calculator, 31 blocks pay 12.6%, 100 pay 16%, 190 pay 17.9%, 250 pay 21.6% and 400 pay 26%. Only building blocks count toward the bracket, not doors.

Build cost per piece

The last column is how long a piece takes to decay completely once its material runs out.

Grade Foundation, wall, stairs Doorway, window frame Floor, roof, triangle foundation, low wall Decays fully after
Wood 200 wood 140 wood 100 wood 3 hours
Stone 300 stone 210 stone 150 stone 5 hours
Sheet metal 200 metal fragments 140 metal fragments 100 metal fragments 8 hours
Armored 25 HQM 18 HQM 13 HQM 12 hours

Doors are billed on their craft cost: wooden door 300 wood (double 350), sheet metal door 150 frags (double 200), garage door and ladder hatch 300 frags each, armored door 20 HQM (double 25).

A worked example: a duo 2x2 in stone

Take an ordinary duo base: four square foundations, five ground-floor walls with a doorway and two window frames, an internal wall with a doorway, four floors, an upper floor with six walls and two windows, a staircase and four roof pieces. That is 31 blocks (17 full-price, 6 openings, 8 half-price) for 7,560 stone of build cost, plus a garage door and two sheet metal doors at 600 frags.

At 31 blocks the blended rate is 12.6%, so the TC asks for 952 stone and 76 metal fragments every 24 hours. A week is 6,664 stone, seven stacks of 1,000, plus 532 frags. Upgrade the foundations and the five outer ground walls to sheet metal and the bill becomes 612 stone plus 302 frags a day: two bills to keep topped up instead of one.

High external walls since Power Trip (August 2026)

High external walls stopped being free. The Power Trip update on 6 August 2026 gave them a static upkeep cost of 20%, which Facepunch describes as the middle of the building block range, and the post says outright that external TCs are now more expensive to keep fed and that old compounds should clear out sooner after a raid.

Rust Labs lists 267 stone a day for a high external stone wall and 600 for a stone gate; the wooden versions cost the same figures in wood. Four stone walls and a gate come to 1,668 stone a day, more than the whole 2x2 above, and the 20% is flat whatever the covering TC's block count.

The group tax from Breach and Clear (September 2026)

Breach and Clear, released 3 September 2026, added a tax on top of all of the above based on how many players are on the base. The first four cost nothing, players five to ten add 2% each, every player after that adds 4%, and the tax caps at 300%. Facepunch's own examples are six players authed for +4% and twelve for +20%; twenty works out at +52%. On the duo base, twelve authed players turn 952 stone a day into 1,142.

Who counts is wider than the TC's auth list: anyone authed on the TC, anyone deauthed from it in the last 24 hours, anyone authed on a code lock in the base (guest codes included), and anyone removed from a code lock in the last 24 hours. A visitor given a guest code for one evening is still taxed the next day. Hover over the cost in an open TC to see the rate; server owners can tune or disable it with Decay convars.

What happens when the TC runs dry

Only the parts made of the empty material start taking damage; the rest carry on. The timers run per grade from the moment the material hits zero: twig lasts about an hour, wood three hours, stone five, sheet metal eight, armored twelve, measured full health to rubble on blocks exposed to the outside. Decay works inward from the outermost, highest and farthest-from-TC pieces, and the default server setting scales interior decay to 0.1, so the core goes last by a wide margin.

Getting raided has its own rule: a TC destroyed with resources still in it absorbs up to 24 hours of upkeep on the way out, so the base holds together for a day before decay starts. Factor that in when you price a counter-raid with the raid calculator or read what a raid costs.

No TC at all

With no cupboard, decay starts right away on the same timers, so a twig starter you never got a TC into is an hour from gone. High external walls outside any building privilege start losing health almost immediately too, with an 8 hour decay listed on Rust Labs. A TC costs 1,000 wood, the cheapest insurance in the game.

How to keep the bill down

Count blocks, not foundations. Honeycomb is where the block count explodes. A 190-block stone base pays 10,200 stone a day; wrap it in 30 armored walls and the count hits 220, the blended rate rises from 17.9% to 20%, and the bill becomes 11,398 stone plus 150 HQM, so the armored ring also made every stone block dearer. Armor the core and the doors, not the outer layer.

Keep the tiers few. Every grade is a separate bill, and the one you forget is the one that decays. Stone with sheet metal doors is two bills; stone, a metal core and an armored TC room is three.

Stock a week at once. The TC shows a 24 hour figure, so multiply by seven and fill it; for the 2x2 that is seven stacks of stone and most of a stack of frags. HQM stacks at 100, so an armored base eats slots fast.

Split compounds onto their own TCs, with one caveat. Each structure is bracketed on its own block count, so a detached gatehouse or external TC section keeps the main base out of the top brackets, which is why multi-TC designs like CorrosionHour's Javelin list separate upkeep for the core and the externals. Since August 2026 the high walls pay 20% whichever TC covers them, so the split saves on blocks, not on walls.

Keep the auth list short. Clear old teammates off the TC and the code locks, and do it a day early, because a deauth keeps counting toward the tax for 24 hours.

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