A method for cleaning batch material from an extrusion die includes introducing at least one gel composition into the die in a manner sufficient to purge the batch material from the die. After the batch material is purged from the die, the die can be treated further so that the gel composition is liquefied and flows from the die.

[Object] To provide a building material manufacturing apparatus that is suitable for suppressing clogging of a screen that screens a building raw material. [Solution] A building material manufacturing apparatus X1 includes at least a screen part 10 and a cleaning mechanism part 40. The screen part 10 includes at least one screen sheet 12 that has an inclination and that has a screen mesh. The cleaning mechanism part 40 includes a scraping part 40a. When the apparatus operates in a building material manufacturing mode in which a building raw material M is supplied to the screen sheet 12 and the screen sheet 12 is performing a wave motion, the scraping part 40a is separated from the screen sheet 12, and, when the apparatus operates in a cleaning mode in which the building raw material M is not supplied to the screen sheet 12 and the screen sheet 12 is not performing a wave motion, the scraping part 40a rotates in contact with the screen sheet 12.