Wood frame: 5 wood to make- 100 durability
Upgrade 1: 10 wood- 200 durability
Upgrade 2: 10 wood- 200 durability
Upgrade 3: 20 iron- 300 durability
Upgrade 4: 40 iron- 1000 durability
Upgrade 5: 40 iron-1000 durability
Upgrade 6: 10 concrete mix- 3000 durability
Upgrade 7: 10 concrete mix- 6000 durability
Upgrade 8: 10 steep- 10,000 durability
Upgrade 9: 10 reinforced steel- 12,000 durability
When broke down: 12,000 to 6000 to 3000 fully upgraded.
Upgrade 5 only: 1000 to 1000 to 300
Upgrade 2 only: 200 to 200 to 100
Wood log: 20 wood to make- 400 durability
Upgrade 1: 10 wood- 200 durability
Upgrade 2: 20 iron- 300 durability
Upgrade 3: 40 iron- 1000 durability
Upgrade 4: 40 iron- 1000 durability
Upgrade 5: 10 concrete- 3000 durability
Upgrade 6: 10 concrete- 6000 durability
Upgrade 7: 10 steel- 10,000 durability
Upgrade 8: 10 reinforced steel- 12,000 durability
When broke down 12,000 to 6000 to 3000 fully upgrade.
Upgrade 4 only: 1000 to 1000
Upgrade 1 only: 200 to 200
Hope this helps.