How to Build a Basement in The Sims 4


Melizza Jane Tacang

Writer and Storywriter

Melizza is a part-time writer for PlayerAssist and a full-time mom. When she's not fussing over her kids, she writes game guides on cozy simulation games like Stardew Valley and The Sims 4. She's mostly seen playing cute indie games on her laptop and Nintendo Switch. Melizza also likes revisiting her childhood survival horror games and classic RPGs because she's a sucker for nostalgia. Aside from video games, Melizza is also into anime, philosophy, true crime, and Pedro Pascal.


The Sims 4 has various building tools when it comes to customizing a house. You can freely manipulate the size of the walls, make a foundation, or build columns to achieve the ideal home you have always wanted. Another interesting tool that you can play with if you are going to, say, build a bunker or an underground lair for witches or vampires is the Basement Tool. This guide has everything you need to know about creating a basement in The Sims 4, so keep scrolling to find out more. 

How to Build a Basement in The Sims 4

Making a Basement

Building a basement is just as easy as making a regular room. But there are some factors you should consider when making the perfect basement for your house.

  1. Enter Build/Buy Mode, select Walls and Empty Rooms, and click on the Basement Tool or the Custom Basement Tool. You can also look for their names in the search bar. Basement 1
  2. Create your basement room the same way you usually build rooms. With the Basement Tool, simply head to the ground floor, drag your mouse to make a room, and release it until you are satisfied with the size. It is also plausible to make your basement bigger than the ground and upper floors. Basement 2
  3. Before you start putting some items, you might want to place some stairs or ladders first. It would be impossible for Sims to access the basement without stairs.Basement 3
  4. Add floor tiles between the basement walls. Keep in mind you cannot place any windows or doors on the outer basement walls since it’s underground. Basement 4
  5. Put some lights to illuminate the rooms to clearly see the area. And finally, you can now design the room in any way you see fit for your basement. Basement 5

The basement feature allows you to create a room underneath the ground floor without foundation. Adding a foundation to make a basement might be something you were accustomed to doing in The Sims 2 and the unpatched version of The Sims 3.

However, in The Sims 4, using the basement tool under an existing foundation may cause a lump on the ground floor and distort the terrain due to the height of the basement walls.

Basement DistortedTerrain

Going to the underground level and using the Wall Tool, Room Tool, or Custom Room Tool to build a basement will prevent that from happening. This method is a lot easier and preferred by most people. In addition to that, you can have a total of two basements in a house, making it possible for you to build a six-story mansion.

Personalizing your Basement

Most players would spend hours modifying their interior design and fiddling with the environment. If you are among those players, here are some suggestions on turning your ordinary basement into a room that may be tailored to your preferences.

Underground Pool

Basement Pool

An underground pool paired with a bar can make a grandeur pool party fit for a Sim living in the city. Again, you can build a pool similarly to how you make it on the ground level, but you will not be able to stretch it out to the edge of the basement.

Styled Rooms

Basement Styled

You may browse styled rooms in the Build/Buy Mode or navigate the Gallery to search for rooms created by other Sim players. Pre-made rooms can also be placed in the basement. Although, any windows or doors will disappear once you set them below ground.

Two-floored Basement

Thinking of building an underground laboratory? Or how about a teen hangout basement? Those would look good with split-level floors. To make a two-floored basement, follow these steps below:

  1. Create your first basement floor in any shape that you like. And then, add the sub-level room, which will later become an open area. Basement split1
  2. Go back to the first basement level and draw a line that will divide the room into two. Basement split2
  3. Click on Remove Floor to delete one of the floor’s rooms. Basement split3
  4. Avoid removing the wall that connects the two rooms, as it will cause the floor you just deleted to reappear. Instead, replace the wall with fences or a spandrel. Basement split4
  5. Lastly, add the stairs to link the two floors in your basement. Basement split5

Open Basement

With an open basement, you can make a beautiful sunken garden or construct an underground entrance to your subsurface pad. To build a basement without a ceiling, you can follow the easy step-to-step guide below:

  1. Build a basement floor. Basement Open1
  2. From the underground, go up a level. Basement Open2
  3. A thick yellow outline will appear above the basement if you click on it. You may select Remove Ceiling to turn it into an open basement. Basement Open3
  4. Add some stairs and furnish the basement as you please. Basement Open4
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