One of the most satisfying parts of playing Subnautica is designing a custom base that fits all your exploration and survival needs, and few features are as fun to customize as a creature containment bay. If you’ve ever run out of space to store rare eggs, house passive creatures separately from aggressive ones, or build out a self-sustaining food source, a two-story setup solves all those problems. This guide breaks down exactly how to make 2 floor containment bay subnautica players can rely on, with no glitchy workarounds that break after game updates. I’ve tested this build across three full playthroughs, and it works for all recent versions of the original game.
Pre-Build Prep: Required Materials and Site Selection
Before you pull out your habitat builder, you’ll need to gather all required materials first to avoid mid-build trips back to resource nodes. For a basic two-story containment bay, you’ll need 12 titanium ingots, 8 glass panels, 4 lubricant, 2 lead, and a fully charged habitat builder. You’ll also want at least 3 extra power cells for your base, since containment bays draw a small but consistent amount of energy to maintain pressure and water circulation.
Site selection is just as important as having the right materials. You’ll want to build in an area with at least 25 meters of open water vertically, so the top of your second floor doesn’t stick out of the surface and cause pressure leaks. Never build your containment bay directly adjacent to a bulkhead or scanner room, because their overlapping hitboxes will create unexpected leaks that are almost impossible to fix without tearing down the whole structure. Avoid building too close to leviathan spawn zones too, as repeated collisions can damage your base’s hull integrity over time.
Core Steps to Build a Functional 2 Floor Containment Bay in Subnautica
Start by placing a flat foundation block where you want your first containment floor to sit. Don’t use sloped or angled foundations, as they will throw off the alignment of the upper floor and break the vertical connection between the two containment units. Next, place a standard multipurpose room directly on top of the foundation, making sure it is perfectly level with the habitat builder’s on-screen grid guide. Install the containment bay module inside the first multipurpose room, and wait for it to fill completely with water before moving on.
Once the first floor is fully set up and connected to your base’s power grid, place a second multipurpose room directly on top of the first one. Do not rotate the second room even a single degree, even if you think it will make the hatch easier to reach. Misalignment is the number one cause of leaks between two-story containment bays, so take your time to line it up perfectly. Install the containment bay module in the top room, then swim into the first floor containment unit and look up at the ceiling. You’ll see a small removable panel in the center of the shared wall between the two rooms – interact with it to open the vertical passage between the two floors.
Before you add any creatures, test the build to make sure it works properly. Swim from the bottom floor to the top floor to confirm there are no invisible barriers, and check your base’s hull integrity meter to make sure there are no unreported leaks. Common mistakes to avoid during this process include:
Always test the vertical connection before adding any creatures or eggs, because fixing a sealed passage after the containment is full will require you to drain both floors, which can kill any creatures you’ve already placed inside.
Maximizing Space and Functionality in Your Two-Story Containment
Now that your basic two-story containment is built, you can customize it to fit your specific playstyle. Many players separate their units by creature type: keep aggressive creatures like stalkers and sand sharks on the top floor, and passive, food-safe creatures like peepers and bladderfish on the bottom floor so you don’t have to worry about attacks when you swim in to harvest resources. You can also dedicate one floor entirely to egg incubation, which makes it easy to monitor hatching progress without disturbing mature creatures.
If you’re like most long-time Subnautica players, you’ll want to add extra storage and monitoring tools around your containment bay to keep track of creature eggs, research samples, and spare building supplies. Standard wall-mounted lockers work well enough, but they can quickly clutter up the narrow walkway around the containment unit, making it hard to access hatches or repair leaks quickly if something goes wrong. Many players look for optimized base storage layouts that keep supplies within reach without wasting valuable floor space, and Ind Slots is a great resource for finding compact, easy-to-build storage configurations that fit perfectly around multipurpose room structures.
Add a specimen analyzer right outside the containment hatch to scan new creatures as you catch them, and place feeding blocks on each floor to cut down on time spent restocking food. Place feeding blocks at least 2 meters away from the vertical passage, because larger creatures like Reefbacks can get stuck trying to reach food if it’s too close to the opening. You can also add small flood lights inside the containment unit to make it easier to see rare, nocturnal creatures when you visit at night. Avoid placing more than 10 large creatures per floor, as overcrowding will cause the containment bay to lose integrity over time and lead to unexpected leaks.
Troubleshooting Common 2 Floor Containment Bay Issues
Even if you follow every step perfectly, you might run into a few common issues with your two-story containment bay. The most frequent problem is small leaks along the seam between the two multipurpose rooms. If you see this, first check that both rooms are perfectly aligned – even a 1-degree misalignment can cause a small leak that drains your base’s power over time. If alignment isn’t the issue, check for small pieces of coral or debris stuck in the seam between the two rooms, as these can break the airtight seal.
Another common issue is creatures disappearing from the containment unit overnight. This is almost always a pathing problem, not a game bug. Check that the vertical passage is completely clear of any decor or misplaced items, and make sure you haven’t accidentally sealed the passage with a wall panel or window. If creatures are still disappearing, try reducing the total number of creatures in the unit, as overcrowding can cause pathing errors that make creatures despawn.
If you’re having trouble with the top floor not filling with water, first confirm that you installed a containment bay module in the top room, not a regular empty room module. If the module is correct, pick it up and replace it – this resets the room’s internal data and fixes 90% of water fill issues. If you experience persistent glitches after an update, pick up and replace both containment bay modules, as game updates occasionally reset the collision data for custom base structures.
Now that you know how to make a 2 floor containment bay in Subnautica, you can expand your aquatic collection to include every creature in the game without running out of space. I’ve used this exact build for my last two playthroughs, and I even expanded it to three floors to house all the rare deep-sea creatures I found on my trips to the Lost River. You can tweak the design to fit your base’s layout, just make sure to keep the core alignment rules in mind to avoid leaks and glitches. It’s the perfect way to add a fun, functional feature to your base that makes surviving on 4546B feel a little more like home.
