When creating walls, do you prefer them in or out?

[Beef Bucket]

I prefer my brushes on top of eachother, but to be honest I never really considered any other option

 

[nᵗʰSonata]

I usually make walls adjacent to the floor, because then everything is within nice squares. However, I will place them on top of the floor if the layout of the map requires me to

 

[FishyUberMuffin]

I like on top

 

[200]

On top for sure. Are the walls connected with only one edge? Too dangerous, better make them 32 units more fat and stand on the floor just in case any leak occurs.
But also, I like to get the exact amount of units that my room takes by clicking on the floor.

 

[Infomaniac]

I would do it ontop because I feel it looks better and it doesn't take up alot of space