The Crafting Silo is a building that was slowly released to players on July 13th, 2011. You can harvest certain animals and trees to get materials that you can store in the Silo and use to make goods in your Craftshop. You need Tin Sheets, Hinges, and Screwdrivers to expand the Crafting Silo. Since November 10th, 2011 the Crafting Silo can be expanded to hold 50 Materials more. You can make the expansion on each farm where you have placed the Crafting Silo and get space for 50 more Materials on each.
In October 2013, the capacity of the Crafting Silo could be expanded to a maximum of 2075 in increments of 25. To increase the capacity by 25, you need 12 aluminum siding, 12 red beam, and 12 screw.