Builder Base Hammer Jam: 50% Off Upgrades & Tips

Supercell is finally giving Builder Base some love. The Builder Base Hammer Jam event runs from May 17 to May 31, 2026, and it’s a full two weeks of 50% off upgrade costs and times — including the Star Laboratory. You also get a 4x star bonus, extra event tasks, and free Clock Tower Potions and Star Jars. If you’ve been ignoring your Builder Base, now’s the time to jump back in.

Why This Event Matters

Let’s be honest: most players only grind Builder Base for the 6th builder (B.O.B). That extra builder changes everything in the Home Village. This event makes hero upgrades — normally a painful lock — way cheaper and faster, so you can check off B.O.B requirements with less hassle.

Rush to Builder Hall 9

If you’re below Builder Hall 9, rushing is the optimal play. Higher Builder Halls unlock more upgrades, better troops, and the 6th builder — all of which give you long-term value. There’s no point sitting at a low level maxing walls while the real prize waits at the top.

Upgrade Priorities

During the event, focus on upgrades that pay off long-term:

• Hero upgrades
• Army Camps
• Star Laboratory
• Key defenses (like Mega Tesla, Roaster)
• Anything needed for B.O.B control

Skip traps, decorations, and low-impact upgrades like crushers. Those can wait.

Clock Tower Timing Trick

Clash of Clans Gems

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