Currently in House Flipper 2, there are no columns in the store to purchase. This means that you'll need to get a little creative and make your own outside any home you decide to flip.
House Flipper 2 column constructions
Unlike the first House Flipper, House Flipper 2 is missing a lot of DLC that will probably be coming in the near future. There are a lot of items missing that you probably noticed, from curtains to holiday decorations. Columns and decorative vertical beams are one such missing thing that has stood out a lot to me.
Use the building tool to make a column
Related: 10 Best House Flipper 2 Mods
Once you unlock the ability to build in homes, you can use the build tool to do all sorts of things from replacing windows to making additions. If you make a 1x1 build to the ceiling, you can create a column. All you need to do is build up the column using the build tool, then use the Surface Finishes menu to make it look like brick, wood, or whatever other surface you want it to look like. You can use the rotation option in the shopping menu to change which direction the grain is going on the beam. Unfortunately, this means that the column will always be square, but they usually turn out pretty nice looking.
Use decorative blocks in different colors
Another option is to build a column with Breeze Blocks. You can choose the color of the blocks to create a fun design on a column; the holes in the blocks will create a unique looking column outside of any house.
Use ceiling beams to make columns against walls
There is a whole selection of ceiling beams that you can use to make columns, but with one big caveat: they must be up against a wall. These beams won't stand in the middle of the floor on their own. But thankfully, you can add these beams next to a wall, then immediately knock the wall down. The beams will remain upright where the wall previously was without any support.
For more House Flipper 2, check out House Flipper 2 Sandbox Mode, Explained on Pro Game Guides.