Unlocking the sixth builder in Clash of Clans completely transforms your home village progression. Instead of waiting weeks for major town hall upgrades, having B.O.B on your team cuts down upgrade bottlenecks significantly. The grind used to run through O.T.T.O, but Builder Base 2.0 streamlined the requirements into a structured checklist. If you want that extra worker without wasting months on inefficient maxing, you need a targeted rushing strategy.
Getting B.O.B isn't about playing fair with your Builder Base; it's about treating the second base purely as a resource engine. Let's break down the exact requirements, the mistakes that trap casual players, and the fastest path to claiming your extra builder.
Core Requirements for Unlocking B.O.B
To unlock B.O.B Control at Builder Hall 9, you must fulfill four specific criteria. You don't need to max out every building on your second base, but you do need to hit these specific targets:
- Gear up three home village defenses: You must upgrade a Double Cannon to level 4, an Archer Tower to level 6, and a Multi-Mortar to level 8 in the Builder Base, then use your master builder to gear up the matching defenses in your main home village.
- Upgrade any troop to level 18: Your Star Laboratory needs to push a single troop all the way to level 18.
- Upgrade any defense to level 9: You need at least one Builder Base defense upgraded to level 9. The Multi-Mortar counts toward this requirement.
- Accumulate 45 combined hero machine levels: Your Battle Machine and Battle Copter combined must reach level 45.
The Builder Base Rushing Strategy
Most home village players make the fatal mistake of trying to max every single defense and wall before upgrading their Builder Hall. That approach will delay your sixth builder by six months or more. Builder Base 2.0 rewards aggressive rushing.
You should upgrade your Builder Hall as fast as your resource storages allow. Walls contribute nothing toward B.O.B, and low-level defenses don't matter when your sole goal is reaching Builder Hall 9. Focus entirely on unlocking the necessary buildings, keeping your Star Laboratory busy, and pumping resources straight into your heroes and required upgrades.
For official game updates and patch notes regarding builder mechanics, check out the Clash of Clans Official Website.
Step-by-Step Breakdown of the Four Tasks
1. Home Village Gear-Ups
You cannot gear up your main village defenses until your Builder Base variants hit the required thresholds:
- Cannon: Requires a level 4 Double Cannon in the Builder Base and a level 7 regular Cannon in your home village.
- Archer Tower: Requires a level 6 Builder Base Archer Tower and a level 10 home village Archer Tower.
- Mortar: Requires a level 8 Multi-Mortar in the Builder Base and a level 8 standard Mortar at Town Hall 10 or higher.
Pro tip: Use a Book of Building on the Multi-Mortar gear-up if you have one spare. It takes 14 days, making it one of the highest-value magic item uses in the entire game.
2. The Level 18 Troop Shortcut
Grinding a standard troop from level 1 to level 18 takes seventeen separate laboratory upgrades, which wastes massive amounts of time. Instead, push your Star Laboratory to level 9 and utilize high-level unlocks. If you unlock and upgrade newer high-tier troops like the Electro Fire Wizard, you can hit level 18 with far fewer intermediate steps. Check community tools and stats on Clash Ninja to track your lab upgrade timers accurately.
3. Hitting a Level 9 Defense
This requirement is practically free if you plan your progression correctly. Because you already need a level 8 Multi-Mortar for the home village gear-up, pushing that exact Multi-Mortar one step further to level 9 satisfies this requirement simultaneously. Never waste builder time upgrading random defenses to level 9 when the Multi-Mortar does double duty.
4. Balancing Your Hero Machine Levels
The 45 combined levels between the Battle Machine and Battle Copter represent the longest bottleneck in the entire unlock process. Because the Battle Copter unlocks later at a base level of 15, a popular efficient split is getting your Battle Machine to level 20 and your Battle Copter to level 25. Never let your hero builders sit idle. Whenever you have the elixir, put your heroes down for an upgrade immediately.
Common Mistakes That Add Months to Your Grind
- Upgrading Builder Base Walls: Stop spending gold or elixir on walls. They do not count toward B.O.B, and opposing armies will still easily crush a rushed base anyway.
- Letting the Star Lab Sit Idle: Your laboratory should never stop researching. Even if you aren't focusing on regular multiplayer attacks, keeping research active is mandatory for the level 18 troop requirement.
- Ignoring the Clock Tower: Boost your Clock Tower daily. It accelerates build times and resource generation significantly, giving you a massive long-term advantage.
- Wasting Raid Medals: Spend your weekly Raid Medals at the Trader for Builder Base gold and elixir. This provides millions of extra resources over a few months without requiring extra attacks.
Frequently Asked Questions
Can I unlock the 6th builder without rushing the Builder Base?
You can, but it will take you over a year instead of three to four months. Rushing is mathematically the only efficient way to meet B.O.B's requirements without stalling your overall game progress.
Do home village walls count toward any requirements?
No. Home village walls and Builder Base walls are completely irrelevant to unlocking B.O.B. Focus your resources strictly on defenses, heroes, and the laboratory.
What is the best magic item to save for this grind?
Save your Books of Building for the Multi-Mortar gear-up and your Books of Heroes for high-level Battle Machine upgrades where build times stretch past several days.
Do I need to unlock every Builder Base troop?
No. Focus strictly on the single troop you chose to take to level 18 and the farming army you use for daily attacks. Unlocking other troops early only drains resources that should go toward your heroes and laboratory.
