Warning: this also means that you can build structures closer together than the default because pathing isn't checked, this can cause unit produced from these structures to get stuck as there aren't empty corridors between the structures.
It would be a better idea to use a custom tileset, just use wc3 viewer to extract the tile you need then import it into your game [TerainArt/*tileset name here*/] over a tile you weren't using but is normally buildable.
Also consider using an app like WEU to use larger tilesets.
Draz
P.S. if you do use WEU, stay clear of the "advanced" triggers, they leak.