Yes, even the houses were usually plastered and whitewashed. Plastering the outer walls protects the mortar between the bricks so it's kinda important. Not all of them were bright white though, they could vary in colour. You can even see this today when some castles/towers are called white (ie White Tower of London) It was common thing to do at that time. Source: I am a civil engineer and studied history of Architecture in Czechia)