Easy to build, ram 4 Posts into the ground and attach a thatch or shingle Roof that can be moved up and down. Low maintenance, the Posts could last up to 40 years, the thatch would Need changing occasionally.
Widespread in northern Europe in medieval times but not so common These days.
Thought to have originated in Holland, The oldest written source is from 1022.
Although they are not common These days, they are coming back, especially in Holland where they are called Hooiberg (Hay mountains) and a society (the Hooiberg Museum) is promoting thier use.
Like all things that look simple..they aren´t. It´s not just a case of bunging loose hay under the Roof and Job done. There´s a lot of specialised knowledge needed to stack and care for the hay as told by the ;
Dutch Barn Preservation Society
Hay barrack in the Velislai biblia picta (Velislaus Bible or Velislav's Bible ) 1325–1349.