Originally posted by CharonJr: Hmm, if I understand the results correctly they don't stack, but FotA is applied before and in addition to any other reductions.
He lists the 80 robe being forged for 22 with a dwarven hammer while both FotA and Steel Ovens are active.
I was referring to what would happen if there were TWO sites with construction bonusses in the same province, such as the Steel Ovens AND the Ancient Forge.