Flood tests for roof systems

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Author Message Tracy Van Niel, FCSI, CCS Senior Member Username: tracy_van_niel Post Number: 270 Registered: 04-2002 Posted on Wednesday, February 04, 2009 - 09:09 am:    We need to specify a flood test area for a roof system at a hospital. The desire is to do the flood test in a designated area of the roof. We currently do not have wording for that type of event in our specifications so I'm hoping someone can help me out with wording? Thanks! Tracy L. Van Niel, FCSI, CCS Lynn Javoroski CSI CCS LEEDŽ AP SCIP Affiliate Senior Member Username: lynn_javoroski Post Number: 847 Registered: 07-2002 Posted on Wednesday, February 04, 2009 - 09:23 am:    How's this (from a vegetated roof section): A. Flood test designated area for leaks, per ASTM D 5957, after completing membrane roofing. Install temporary containment assemblies, plug or dam drains, and flood with potable water. 1. Flood to an average depth of 2-1/2 inches, with minimum depth of 1 inch and maximum depth of 4 inches Maintain 2 inches of clearance from top of sheet flashings. 2. Flood each area for 24 to 72 hours. And I'd definitely read ASTM D 5957... George A. Everding, AIA, CSI, CCS, CCCA Senior Member Username: geverding Post Number: 460 Registered: 11-2004 Posted on Wednesday, February 04, 2009 - 10:31 am:    Flood Test More Flood Test Previous discussions that I found helpful. George A. Everding AIA CSI CCS Cannon Design - St. Louis, MO Tracy Van Niel, FCSI, CCS Senior Member Username: tracy_van_niel Post Number: 271 Registered: 04-2002 Posted on Wednesday, February 04, 2009 - 11:00 am:    Thanks for the links, George. A lot of times when I try to do a key word search of the archives, I have a hard time finding what I want ... must be using the wrong key words. Tracy L. Van Niel, FCSI, CCS Mark Gilligan SE, CSI Senior Member Username: mark_gilligan Post Number: 115 Registered: 10-2007 Posted on Wednesday, February 04, 2009 - 12:53 pm:    If this is a new roof on an existing building you might want to have a structural engineer verify that there are no structural issues. Multiple roofs installed can reduce the live load capacity. Also some old roof structures can be marginal. If you are dealing with a new building the 4" maximum should not be a problem since it is about 20 psf which is the design live load. Given the recommendation that the depth be between 1 and 4 inches and the minimum roof slope of 1/4" per foot the area to be flooded will be limited to 12' in the direction of the slope. Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 630 Registered: 05-2003 Posted on Wednesday, February 04, 2009 - 01:08 pm:    I disagree with this notion of flood testing a roof, for waterproofing, definitely, but for many roof systems, flood testing is not appropriate. Remember roofs are weatherproof not waterproof..waterproofing systems prevent the passage of water under hydrostatic pressure, i.e. standing water. We have been warned by manufacturers that we run the risk of warranty exclusion if we require flood testing. Also NCARB does not recommend conducting flood tests as part of quality control for new roofs. Instead we specify that contractor confirm the integrity of the roof installation using visual observation, Thermal or Radiation scans. RH (Hank) Sweers II RA CSI CCS Senior Member Username: rhsweers2 Post Number: 9 Registered: 08-2005 Posted on Wednesday, February 04, 2009 - 01:42 pm:    I doubt that NCARB would say much about roof testing, but maybe NRCA would! Jerome J. Lazar, RA, CCS, CSI, SCIP Senior Member Username: lazarcitec Post Number: 631 Registered: 05-2003 Posted on Wednesday, February 04, 2009 - 02:11 pm:    correction - NRCA, not NCARB...long nite, never enuf sleep. Jim Brittell Senior Member Username: jwbrittell Post Number: 61 Registered: 08-2004 Posted on Wednesday, February 04, 2009 - 08:02 pm:    Where I work, we set up sprinklers on the roof and run them for 48 hours, which is way more than the typical southern California rain storm. Mark Gilligan SE, CSI Senior Member Username: mark_gilligan Post Number: 116 Registered: 10-2007 Posted on Wednesday, February 04, 2009 - 08:17 pm:    I hope you are recycling the water given the current drought in California. Jim Brittell Senior Member Username: jwbrittell Post Number: 62 Registered: 08-2004 Posted on Thursday, February 05, 2009 - 07:37 pm:    Mark - we use non-potable water (i.e. irrigation water) for the test. ken hercenberg Senior Member Username: khercenberg Post Number: 11 Registered: 12-2006 Posted on Monday, February 09, 2009 - 06:17 pm:    My biggest fear with flood testing conventional roofing systems, after structural collapse, is what happens if there are leaks? At best, you have just saturated your insulation. With concrete roof decks that are watertight, you may not realize that you have a leak. With metal decks, the water can run a long way before entering the building. Visual inspection provides limited success at best. Infra-red tells you where you have wet insulation but not where the leak is. I'm still a believer in the EFVM method of testing both roofing and waterproofing membranes. I have been on roofs where IR, flood, and visual inspection couldn't find the leaks; EFVM took a matter of minutes, once it was set up, to find 16 leaks where a handful of architects, a roof consultant, a roofer, a general contractor, and two facility managers couldn't find one leak after three separate sessions of active searching.