The fifteen hearths of Quoygrew

Quoygrew is a 1,000 year old house on Westray which was lived in by Vikings from 950 AD, shortly after they arrived in Orkney, and only stopped being used sometime in the 1930s. In the house there were 15 hearths discovered, one on top of another, from the 13th to the 16th Century with one replacing another as the floor grew thicker with dust, dirt and debris. If I don’t vacuum my lounge soon the same will happen to my place.