Workshop

From HiveWiki

If you have few vassals, upgrade your Workshop and get more out of their power since improved building quality by Workshop makes the Vassals inside more productive. Upgrades apply to defensive & offensive structures as well as production buildings.

Workshop upgrades the efficiency level of buildings.
You can upgrade any building, except for your Court.
There is no limit to how high you can upgrade a building.

Building	Requirements	Allows building of
Workshop	Garrison	If Workshop size 5: Church

[edit] Building Upgrades

All buildings start out at level 0 (no bonus).
Each upgrade to a building increases its level by 1.
Each upgrade increases the building's efficiency bonus by 5%.
For a building size 5, upgrading it to level 4 will apparently add 1 vassal to the building. See more in Size and level.

[edit] The Mine and Iron bars

Iron bars bought in the mine increases the rate of production in the workshop
Iron is sold in blocks of 500 bars at an escalating cost
Iron is used up at a rate of ~0.7 per second
The maximum efficiency gain possible from buying Iron is +25%
Iron bars cost more the bigger your workshop is
The cost of iron bars rises greatly with each purchased block of 500
We have not yet worked out the rate of cost increases, but it seems that buying Iron bars to increase workshop efficiency becomes less cost effective than simply buying anvils directly after buying just a couple bars.