Storage of Architectural Plans & Drawings

[Museumgirl]

We have a fairly large collection of architectural plans and drawings that we are just starting to organize. Some of the plans have been stored flat, while others have been rolled. We also have some original pencil drawings in the collection.

I'm wondering how other museums have handled the storage of this type of collection. Do you keep the rolled ones rolled? If you un-roll them, do you use humidification chambers?

Thanks for your help!!!