It All Adds Up

At first glance this may seem like an insane achievement to get, even as a guild, however, with the new guild perk Cash Flow allowing such repairs might become very much affordable.

Although it seems fairly obvious after thinking about it, only repairs done via the "Repair from guild bank" seem to contribute towards this, or at least that is my guess. I only use personal repairs while questing out of habit, and the guild's progress on this achievement is still 0. If you want to get it ASAP, turn on guild repairs for all ranks and just have people deposit money in the bank to replace what they repaired with, since you wont get the free 5% until rank 5.

As of 5.2, the armory can again properly show the progress for this achievement