Ash houses were used as a safe repository for hot wood ash from domestic fires. They prevented sparks from the embers causing fires in the thatch of roofs. Ash houses were also places where the ash could be kept dry before being used to supply potash. Potash is used as a manure on arable fields.
This photograph shows a simple Lustleigh ash house with typical corbelled stone roof and single door. The ashes were loaded and removed through the single door.