Expanding your lair is vitally important to the success of your evil schemes. EG1 and EG2 have slightly different building processes for lair construction, so both are described here in their own sections.

Evil Genius

Building Rooms

To build a new room, right-click on unmined rock (or inside an empty Hotel or Topside Shack) to bring up the room list. Select the desired room type from the list to enter the blueprint phase. Left-click on minable rock to add a blueprint tile and right-click on an existing blueprint tile to remove it. Click-and-drag to add or remove a rectangular area instead of a single tile.

Rooms must be at least two tiles wide. Blueprint areas that are too narrow will be colored red, and the blueprint cannot be confirmed while any part of it is too narrow. Doors can be placed in any part of any room that is exactly two tiles wide and unobstructed on either side, so if you want to be able to close off a room, be sure to leave a gap of the right size.

The total cost of the planned room is shown in the Room Build pane. When you are satisfied with the blueprint, click the arrow on the Room Build pane to confirm the blueprint. If you wish to cancel the blueprint, click the cancel icon. When a blueprint is confirmed, a tag will appear over the blueprint room with a hammer under a "pause" icon, and the build menu will appear.

Demolishing

Right-clicking in a room or on an object will bring up the option to demolish it. Objects marked for deletion will immediately become inactive. Demolition can be cancelled up until a minion arrives to carry it out. Upon demolition, you will receive a refund of 90% of the purchase price of the object or room.

Evil Genius 2

Information pending.