Remodelling is the British spelling of the -ing form of remodel: to change the shape, structure, or look of something, especially a building. A family might do a remodelling of the kitchen — knock out a wall, move the sink, put in new cupboards. Builders, architects, and homeowners use it all the time. American English usually writes remodeling with one l; both spellings are the same word. As a noun, remodelling is the job or the process (“the remodelling took two years”). As a verb form, “they are remodelling the library” is the action happening now. People also stretch it away from houses: a company remodelling its teams, or scientists talking about the brain remodelling itself. The building sense is still the one you will meet first.