The Warehouse is designed to save your resources from being plundered, but it doesn't hold enough to make it worth it. You're better off having another barracks up and having more troops to defend your city from ever being plundered than to have a spot to hole some of your resources up in.
General Information:
The Warehouse stores resources, preventing enemy plundering in the event of a raid or attack. Resources stored in a Warehouse are not able to be taken by an opponent unless the attacking player has researched Privateering (which is only 3% each level, offering 30% on level 10). Warehouse capacity can be increased by researching the Stockpile technology. Each level of Stockpile offers an increased capacity of 10%.
History:
One of the earliest methods of food preservation was sun or air drying. This technique works by removing most of the food's water and thereby limiting activity of the microorganisms. The warehouse finally came to being, which gave the early people a place to store their food.
Upgrading:(your choice if you wanna waste the spot)
Level 1:
Food: 100
Lumber: 1,500
Stone: 1,000
Iron:300
Storage Capacity:10,000
Level 2:
Food: 200
Lumber: 3,000
Stone: 2,000
Iron: 600
Storage Capacity: 30,000
Level 3:
Food: 400
Lumber: 6,000
Stone: 4,000
Iron: 1,200
Storage Capacity:60,000
Level 4:
Food: 800
Lumber: 12,000
Stone: 8,000
Iron: 2,400
Storage Capacity: 100,000
Level 5:
Food: 1,600
Lumber: 24,000
Stone: 16,000
Iron: 48,000
Storage Capacity: 150,000
Level 6:
Food: 3,200
Lumber: 48,000
Stone: 32,000
Iron: 9,600
Storage Capacity: 210,000
Level 7:
Food: 6,400
Lumber: 96,000
Stone: 64,000
Iron: 18,200
Storage Capacity: 280,000
Level 8:
Food: 12,800
Lumber: 182,000
Stone: 128,000
Iron: 36,4000
Storage Capacity: 360,000
Level 9:
Food: 25,6000
Lumber: 364,000
Stone: 256,000
Iron: 72,800
Storage Capacity: 450,000
Level 10:
Food: 51,200
Lumber: 728,000
Stone: 512,000
Iron: 144,000
Storage Capacity: 550,000
*Michelangelo's Script*
**Once again it is only advised to upgrade this in order to get the quest, once you have the quest and you have Privateering level 10 & Stockpile Level 10 researched in your academy, please destroy the warehouse and build a Barracks.**