Builder Hall 9 Guide: B.O.B Control and Lava Launcher

What changes at Builder Hall 9

B.O.B Control is built at BH9 and does nothing until it reaches level 5. Its levels cost no time or resources but each needs a free Master Builder or O.T.T.O and a task completed, in this order: gear up a Home Village Cannon, Archer Tower and Mortar; upgrade any Builder Base troop to level 18; upgrade any Builder Base defense to level 9; and bring the Battle Machine and Battle Copter to a combined 45 levels. At level 5 you can build B.O.B's Hut in the Home Village, and B.O.B works there as a permanent sixth builder.

The Lava Launcher lobs lava with a huge range that burns ground troops standing in it for 20 seconds, but it has a large blind spot and cannot hit air. A second Reinforcement Camp, a fifth Firecrackers, more Spring Traps and Mega Mines, and 180 Walls are also new, and the per-stage defense quota rises from 13 to 14.

The Builder Barracks reaches level 11 for the Hog Glider, a flying troop that dives into defenses and continues on foot as a Hog Rider; from level 15 the dive also stuns. Star Laboratory 9 lets troops reach level 18. The upgrade to BH9 costs 3,800,000 Builder Gold and takes 6 days.

Upgrade priority

A sixth Home Village builder is worth more than any single Builder Base upgrade, so plan BH9 around B.O.B Control. The Mortar gear-up needs a level 8 Mortar (Town Hall 10) and a level 8 Multi Mortar, and it is the longest of the requirements, so start it as early as your Town Hall allows. The gear-up tasks only check that each gear-up has started, not that it has finished.

1. Build B.O.B Control and start the gear-ups you have not done: Cannon, Archer Tower and Mortar.
2. Star Laboratory to level 9, then one troop to level 18. Pick a troop you attack with, such as Baby Dragons or Night Witches.
3. One defense to level 9. The Multi Mortar is a good choice since it also feeds the Mortar gear-up.
4. Battle Machine and Battle Copter to a combined 45 levels.
5. Lava Launcher and the second Reinforcement Camp.
6. Healing Hut to level 5 and the Builder Barracks to level 11 for Hog Gliders.
7. Storages for the 4,800,000 Builder Gold BH10 costs, then the rest.

How to choose a base at BH9

The Lava Launcher covers most of a stage from the middle, so place it centrally and cover its blind spot with a Crusher or Double Cannon. Its burning pools stack and last 20 seconds, which punishes slow ground armies such as Power P.E.K.K.As and Boxer Giants that bunch up. It does nothing against air, so make sure the same area has Firecrackers, Air Bombs or the Roaster.

Hog Gliders target defenses and jump Walls once they land, so they behave like Home Village Hog Riders after the dive. Mines and Mega Mines on the paths between defenses, and the Mega Tesla, are good answers.

With 26 defenses and 14 allowed per stage, you can now make both stages strong. Many players put the Lava Launcher in stage one to punish ground openers and keep enough anti-air for the second stage, where attackers often switch to the Battle Copter or air reinforcements.

Common attack strategies at BH9

Air armies avoid the Lava Launcher entirely. Baby Dragons, Drop Ships and the Battle Copter can clear a stage if you remove the Air Bombs and Firecrackers on one side first. Hog Gliders are the new option: their dive damages and, from level 15, stuns the defense they hit, and the Hog Riders then keep going on the ground.

Two Reinforcement Camps let you bring a real second army to stage two. A common plan is a ground or air army for stage one and a different troop in both reinforcement slots chosen for the stage-two base you see.

Against ground-heavy armies, a Lava Launcher in your path changes the plan; spread the deployment so the burning pools hit fewer troops at once.

Farming and resources at BH9

The Builder Hall holds 1,500,000 of each resource and the Elixir Cart up to 1,400,000. The second Reinforcement Camp alone costs 4,000,000 Builder Elixir and 10 days, and Hero levels cost 3.6 to 4 million each, so Builder Elixir from defenses and the collectors is the bottleneck.

Higher trophy leagues pay more per star and larger Star Bonuses, and losing trophies on purpose to find easy bases costs you loot. The Clock Tower at level 9 gives 30 minute boosts. It speeds up all Builder Base timers, but it does not speed up B.O.B once he works in the Home Village. Save its free boost for the research that takes a troop to level 18, since that is usually the slowest B.O.B task done inside the Builder Base.

Mistakes to avoid

• Leaving the Mortar gear-up for last. It needs Town Hall 10 and takes the longest.
• Spreading Star Laboratory time across many troops when B.O.B needs one troop at level 18.
• Starting a B.O.B Control upgrade when both builders are busy. It needs a free one.
• Counting O.T.T.O's Outpost toward the level 9 defense task. It does not count, and neither do traps or Walls; the Guard Post does.
• Placing the Lava Launcher at the edge, where its blind spot is easy to reach.
• Forgetting anti-air near the Lava Launcher. It cannot hit Hog Gliders, Baby Dragons or the Copter.