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Expert: - 3/11/2009


Question
I need to install additional venting for multi-family dwellings. There are 8 bldg, each is a 2 story 8 plex. My problem is the space between the 2nd story ceiling and the roof (about 24")is holding moisture, and causing the decking to rot. The buildings have flat roofs with torchdown.  Can you outline the proper steps required to install additional pipe vents using torchdown?

Answer
Mark,

I'm not quite sure what you mean by "pipe vents".  If you can detect moisture in the truss space - it would indicate that there is a leak in the system.  Usually the sun provides adequate heat to keep that area dry and free of moisture.

Personally I would not create any more penetrations of the roofing material.  Rather, you could have louvered vents installed in the wall at each end where the trusses bear.  Or, if the roof system overhangs the walls, ventilating grilles in the soffit work well and are away from water intrusion.

A membrane or "torchdown" roof is rather delicate.  If the seams are not "welded" (heat sealed) properly a leak can develop plus there probably are several penetrations from plumbing vent stacks, exhaust fan vents, chimneys, etc.  

If you can access the crawl space, try flooding the roof with a water hose while you are watching in the crawl space.  This is not an easy task and may take hours of investigation since a pin-hole leak is difficult at best to detect.

Check with your roofing contractor.  Some of the membrane products have a venting system that can be installed in a sealed system.  Also, the contractor may have some other suggestions about detecting a leak.

I hope this has been helpful.

Roger  

Construction Industry

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Roger Zona

Expertise

I am experienced in all types of construction: residential, industrial and commercial; single family, multi-family, mid-rise and high rise buildings (16 story office building) as well as remodeling, additions and tenant improvements. I can field most any question that relates to general construction. I have consulted with infrastructure (utility) contractors also and have a good general knowledge of underground utility construction for subdivisions and commercial projects.

Experience

After college, I began my career in the construction industry. I chose to become an apprentice Architect and 4 yrs later I opened my own architectural design firm. Six years later I moved to Florida to buy & develop land and build. I became a State of Florida Certified General Contractor and operated my business for 45 years. I built all types of residential and commercial buildings including warehouses, shopping centers, high rise apartments and office buildings and developed sites for other contractors. I retired and became a consultant to the construction industry. I maintain my license and continuing education requirements, operate a small construction company and write a weekly newspaper column for the Palm Beach Post (a Cox publication) with the byline "Ask The Contractor". I am the "technical editor" for a publisher of books that relate to home maintenance.

Organizations
Previously - NAHA Currently - FLCA (Florida Licensed Contractors Assoc.)

Publications
Palm Beach Post newspaper - weekly Q & A column Happy Herald monthly real estate publication - monthly column

Education/Credentials
Michigan State University University of Detroit BS in Engineering

Past/Present Clients
I built a home in Palm Beach for a member of the Pulitzer Family. I was responsible for the completion of a twin hi-rise condominium project for G.E. Credit. I was a partner in the successful development of a P.U.D. (Planned Urban Development) subdivision. I represented the largest home builder from France (Bati Service, S.A.) in the development of a subdivision and the design and construction of the homes.

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