Charlene, It all depends on what the "mixed-media" art is, on the building you are in, and in the outdoor environmental conditions. Usually HVAC settings for collections do not have to be in such a tight range unless you have very sensitive materials like older photographic collections, parchment, ivory, etc., especially if your collections in there are stable. Historic Buildings especially are vulnerable to tight HVAC settings because the historic materials will react and portions of the building may deteriorate. And if you live in an area with humid hot summers and cold dry winters you need a wider range in your HVAC seasonal ramping, at least 10%. Now when moisture appears on a ceiling it speaks more to what is above the room. Is there signs of old water leaks in the ceiling or are these entirely new? Are there water pipes or drain pipes up there? A fire suppression system? Or ducts (as Mark asked)? Is there no insulation in the ceiling and a hot room above, where condensation may be forming on your ceiling from the temperature difference? Get with your building engineer and figure this out. It may just mean that insulation needs to go into the ceiling. If you have leaking pipes you have a problem. Cheers! Dave David Harvey Senior Conservator & Museum Consultant Los Angeles CA USA www.cityofangelsconservation.weebly.com On Tue, Aug 25, 2015 at 7:58 AM, charlene martin <[log in to unmask]> wrote: > Hi everyone - > > I have one storage room for housing textiles, paper documents, books, and > mixed-medium artwork. > > I have set my HVAC for 65 degrees with a 5 degree season shift, and he > relative humidity for 50% with a 5 percent seasonal drift. > > Is this good for a mixed collection storage room? Has anyone heard of this > causing moisture to be gathering in spots on the ceiling? > > Thank you! > > ------------------------------ > > To unsubscribe from the MUSEUM-L list, click the following link: > http://home.ease.lsoft.com/scripts/wa-HOME.exe?SUBED1=MUSEUM-L&A=1 > ========================================================= Important Subscriber Information: The Museum-L FAQ file is located at http://www.finalchapter.com/museum-l-faq/ . You may obtain detailed information about the listserv commands by sending a one line e-mail message to [log in to unmask] . The body of the message should read "help" (without the quotes). If you decide to leave Museum-L, please send a one line e-mail message to [log in to unmask] . The body of the message should read "Signoff Museum-L" (without the quotes).