I want to build a bathroom outside my home.

Because it is an old house, it is basically matched with the original house, so bricks can be used as walls and 12 walls, that is, single brick walls, mortar plastering, roof color steel tiles, interior walls and floors, wall tiles and floor tiles can be pasted, and you can buy cheaper bricks. If you want to be cheaper, you can use wood instead of sticking bricks indoors.