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Roofing/ceiling insulation

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Question
Hi Bruce,

We have a flat roof on a condo building in Chicago.

Should there be insulation under the roof deck and above the dry wall interior ceiling?

I've been getting water coming through the ceiling and I was told  (since the dry wall ceiling will need to be replaced) that I should cut a square hole through the ceiling dry wall and spray a water-bleach spray above the ceiling to prevent mold from starting to grow until a repair can be made in the spring.

I did that only to find that there is clear plastic holding pink insulation which surprised me because I was under the impression that it would be hollow enough for me to spray around as I was told.

Could this lack of ventilation be part of the problem as to why this roof (which was built in 2006 along with the building) is failing so miserably?

Any advice would be greatly appreciated.

Answer
Joe,

Clearly whomever directed you to perform that function is not aware of the roof assembly configuration above your unit.

The plastic that is tight to the top side of the drywall on the ceiling is a vapor barrier that is best left uncut, but that can be repaired when the ceiling is.  The pink insulation is often situated on top of ceiling directly as with a typical single family dwelling, which then indicates to me that their is an attic space above the insulation layer that should be ventilated to comply with Code.  If the insulation completely fills the cavity and the roof sheathing or deck is immediately above the insulation layer, then yes, a lack of ventilation is of great concern in that particular area.

Unventilated attic spaces can function properly, but often there can be issues related to condensation and moisture build up over time.

Regards,

Bruce Ryan II, RRO
Professional Roof Consultants, Inc.

Roofing

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Bruce A. Ryan II, RRO

Expertise

I offer solid knowlege of all types of Commercial and Residential Roofing, Waterproofing, and, Building Envelope systems. Experience ranges across low slope and steep slope roof systems. I am also well versed in matters regarding condensation and ventilation. I enjoy donating some of my time and knowledge to the betterment of others.

Experience

Bruce Ryan has 20 years of roofing, waterproofing, and building envelope consulting experience with PRC, with 5 years of commercial roofing experience prior to joining the firm. He became Vice President of the company in 1998. Bruce Ryan plays a key role in the development of practical, long-term roofing and waterproofing solutions, along with implementation of on-site forensic studies. Bruce also has a high level of experience with regard to the impacts of roofing materials and construction for demanding clients with heavily occupied structures.

Organizations
Oregon Construction Contractors Board Construction Specifiers Institute National Roofing Contractors Association The Institute of Roofing, Waterproofing, & Building Envelope Professionals Oregon Board of Investigators Installation Masters

Education/Credentials
University of Maryland BS Business & Administration Registered Roof Observer - RCI Private Investigator Certified EIFS inspector - Northwest Wall and Ceiling Bureau Certified InstallationMaster™ - The Installation Masters™ Training and Certification Program (developed by American Architectural Manufacturers Association)

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