Expert: Bruce E. Johnson - 12/3/2008

Question
If an exposed concrete roof deck with terracotta tile finish does not have insulation, will there be any condensation problems?  The climate is hot humid in the summer (temperatures can reach 115 deg F) and the building is airconditioned.

Answer
Hi Drew, are you sure the roof isn't insulated?  Most concrete roof decks that I have done have a 3" polyisoanurate insulation on top with a nail base of OSB to attach the tiles to.  It's kind of unusual for the roofing to be attached directly to the concrete.  However, if the concrete is as you say it is and the underside of the roof is exposed inside the conditioned space the air conditioning may have to work a little harder but any moisture will be handled by the A/C.  As long as the roof itself is waterproof then the moisture will have to come through somewhere else so I don't see a big problem with condensation.  I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com