Best way to upgrade my special event buildings?

[Bosshoof]

What is the best way to upgrade special event buildings? Where do I find the tools?

 

[Jern2017]

You can get upgrades during the event which offers that building.

Later, you may also find upgrades in Daily Challenges, the Antiques Dealer or later events.

 

[Darth Mole]

Look for One up Kits and Renovation Kits as daily rewards or as special event rewards (and also in GE)

 

[Reese7990]

It will take the full event to fully upgrade your buildings, unless you use diamonds to speed up the process. You will earn upgrades by scoring goals, finishing certain amounts of quests, and I believe in the tournaments.

Previous event buildings...Older event building upgrades can be found in the antique shop and also may appear during events. Recent event buildings, you will have to wait till next years event of the same season to see again. Like the Airship will not show up again until next years archeology event.

 

[Agent327]

Look for One up Kits and Renovation Kits as daily rewards or as special event rewards (and also in GE)

Those do not upgrade the building, only the age.

 

[Darth Mole]

Those do not upgrade the building, only the age.

Correct but the OP doesn't specify whether he's wanting to add a level or an age/s.