WestCon Tribune

 

This month's meeting will include a two-part presentation by Westcon member Philip Dregger, PE, RRC, of Technical Roof Services, about unexpected condensation problems.

Air Infiltration

The Enemy of Condensation Control

Considerable effort is spent specifying and constructing roof systems to avoid damage due to excess accumulation of condensation moisture. And, although information is readily available about a roof system's vapor permeablility; little information is available about a major cause of condensation damage - excess air infiltration.

This presentation will review current design procedures (e.g. - building codes, ASHRAE Fundamentals, ORNL Condensation Control in Low-Sloped Roof Systems)., present several case histories illustrating how air infiltration led to condensation damage despite an otherwise appropriately designed and constructed roof system, and offer guidelines regarding how to identify and seal common air infiltration pathways.

 

Underlayment Upgrades -That Sometimes Aren’t

Self-adhering modified bitumen membranes are often installed as continuous waterproofing layers below steep roof systems to enhance weather protection. Sometimes, however, these "bullet-proof" roofs develop an unexpected problem - condensation. The potential problem is that self-adhering modified bitumen sheet type products, although waterproof and quite flexible, are virtually impermeable to moisture vapor transmission. Mr. Dregger's presentation will explain why moisture accumulation occurs in these constructions and will offer some suggestions on how to enhance weather protection and yet avoid problems.

Mr. Dregger is a registered engineer and a registered roof consultant with over 20 years of consulting experience. He is president of Technical Roof Services, Inc., a California based consulting firm that specializes in finding solutions to difficult moisture intrusion problems. Phil is a past director and a fellow of the Roof Cosultants Institute (RCI) and presently serves as RCI's representative to RICOWI. Mr. Dregger has published several articles on roof technology including "The Role of Air Retarders Deserves Closer Scrutiny" referenced in the NRA special report on mechanically attached single ply roof systems and most recently in the national wind design standard ANSI/SPRI/RP-4.