Learn how to build a dungeon how to upgrade traps on mobile in Roblox [GUILDS] Build a Dungeon: roll and place trap parts with Coins, take the trap mastery node, and stop thieves disarming them.
Published: Build a Dungeon Wiki Editorial Team
Table of Contents
How Traps Are Bought and Upgraded in Build a Dungeon
[GUILDS] Build a Dungeon is Exploration Guild's Roblox simulation and tycoon game, still in beta, in which you build the dungeon, fill it with monster units and traps, and defend a dungeon crystal against endless waves of heroes who enter through a one-way entrance and walk the tiles you place. Traps are one of the groups of placeable parts in that catalogue, and recorded builds list them as spike trap, poison trap, tar pit, bear trap, arrow trap, fire trap, falling rocks, oil and lava floor.
Traps reach your dungeon the same way corridors and rooms do: they appear in the roll system and are bought with Coins, the currency that pays for buildings, traps and parts, while Dark Souls stay reserved for monster units. Two things then raise what those traps do:
Upgrade Lever
What It Changes
Where It Comes From
Trap mastery
Raises trap damage for the whole dungeon
A percentage node in the skill tree
Update 7 trap upgrades
Lets placed traps be improved instead of staying fixed
Introduced with the Guilds beta
Oil and lava floor
Keep a hero burning and raise fire damage
Trap and floor parts placed on the same stretch
The skill tree upgrades the dungeon globally rather than one unit at a time. Its nodes include gold rush, soul harvest, unit damage, population, trap mastery and battlecry, and Update 6 moved the 2x Battle Speed upgrade earlier in the tree. Recorded gameplay treats the whole tree as percentage increases to each stat, which is why trap mastery is the node that pays off a trap-heavy corridor.
Fund the rolls: Defeat hero waves and let potion shops sell to the heroes walking past, then spend Coins on trap parts.
Roll and place: Take the traps the roll offers, buy them, and set them on the corridor or room tiles the wave has to cross.
Take trap mastery: Spend skill-tree points on the trap damage node before adding another layer of traps.
Re-check after a patch: Update 7 moved trap upgrades into the Guilds beta, so the upgrade options on a placed trap come from the current update notes and the in-game interface.
What Each Trap Does
Trap choice matters more than trap count, because each part answers a different problem and only one of them buffs damage.
Trap
Documented Behaviour
Spike trap, poison trap, bear trap, falling rocks
Deal damage to the heroes that step on them
Arrow trap
Wall-mounted ranged damage; it is placed on a corridor or room wall facing the hero path
Tar pit
Slows heroes down instead of dealing heavy damage
Fire trap
Fire damage, and the trap that recorded runs rate highest because oil and lava floor both feed it
Oil
A hero who steps on it keeps burning for three tiles, so the fire damage does not drop off
Lava floor
Raises fire damage, which is why recorded builds set it under the fire trap stretch
Monster units cannot attack through walls, and a wall between a unit and the corridor means that unit contributes nothing to the wave. That makes trap tiles the cheapest way to cover a stretch of corridor your units cannot see, as long as the trap line has something behind it to finish the heroes a thief leaves standing.
Tip
Space oil every three tiles, counting the oil tile itself, and cover the same stretch with fire traps and lava floor. Recorded builds do this so the burn keeps reapplying instead of dropping off between oil tiles.
Making the Traps Pay for Themselves
A trap line is a Coin investment, and the wave is what pays for it. The potion shop is one of the main income sources in the game because heroes stop and buy potions on their way in, no matter how many shops sit along the route, and the treasure room is guaranteed to pull heroes toward wherever you placed it. Put both on the long route rather than beside the crystal, and the wave spends time earning Coins before it reaches your traps.
The escape menu shows the hourly rate your dungeon is producing, and it scales from your highest wave, so a stalled Coin-per-hour figure means the layout is not converting waves into income. Recorded runs also show a failure restarting from the nearest checkpoint instead of wave one, so a trap layer that fails is a layer you can rebuild with the Coins from that attempt.
Upgrading Traps on a Phone or Tablet
Roblox runs this game on phones and tablets as well as PC, and the trap system itself is the same on every device: the same roll screen, the same Coins, the same placeable parts. What changes on a touchscreen is only the input. The official page lists a six-player server size and no voice chat or camera support, so there is no extra interface layer to manage on a phone, and the practical problem becomes placement precision rather than performance.
Budget Coins for traps before you decorate, because every part competes for the same floor space.
Place the arrow trap on a wall tile that actually faces the corridor the heroes walk, since it is a wall part rather than a floor hazard.
Keep the oil, fire trap and lava floor stretch on a section the heroes must cross, not on a shortcut they can skip.
Take the trap mastery node before rolling for more traps: a percentage increase lifts every trap you already own.
Warning
Do not build a corridor out of traps alone. Thief heroes disarm traps within a one-tile radius around themselves, healers restore health to the rest of the wave, and archer heroes can shoot through walls even though your own monster units cannot attack through a wall at all. Keep monster units on the tiles the heroes must cross, and treat the traps as the layer that softens the wave on the way in.
[ ] Is every trap sitting on a tile the heroes are forced to walk?
[ ] Is the oil, fire trap and lava floor stretch on the mandatory route?
[ ] Have you taken trap mastery before buying another trap?
[ ] Does a monster unit cover the corridor behind the trap line?
[ ] Have you re-read the update notes since Update 7 changed trap upgrades?
Frequently Asked Questions
How do I upgrade traps on mobile in Build a Dungeon?
Traps are rolled for and bought with Coins, and their damage is raised by the trap mastery node in the skill tree. Update 7 brought trap upgrades into the Guilds beta, so check the current update notes and the in-game interface for what can be upgraded on a placed trap.
Do mobile players buy traps separately from PC players?
No. Coins buy buildings, traps and parts on every device, and Dark Souls are the currency for monster units. Only the controls differ, because a touchscreen replaces the mouse and keyboard.
Why did my traps stop damaging the wave?
Look for a thief. Thief heroes disarm traps within a one-tile radius of themselves, so a trap-only corridor opens up as they walk it. Monster units behind the trap line are what finish those heroes.
Which trap should I upgrade first?
Fire, because it is the only trap element with two other parts feeding it. Oil keeps a hero burning for three tiles and a lava floor raises fire damage, so a fire trap on that stretch hits harder than the same trap alone. Spike, poison, bear trap and falling rocks simply deal damage, and a tar pit only slows heroes down.
How much does a trap upgrade cost?
Official upgrade prices and trap damage values have not been published, so check the in-game interface for current costs.
