Sealing GFRC Joints

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Author Message Brett Wilbur New member Username: bwilbur64 Post Number: 1 Registered: 02-2018 Posted on Thursday, February 22, 2018 - 02:30 pm:    Hi everyone, been so long, glad to be back. Perhaps you all can help me out. A current client wants to save money by deleting the back up sealant bead in a dual bead joint system between GFRC siding panels. The turn-back fastening flange on the panel is 1.5-inches. GFRC is being fabricated and installed by Willis Construction. This joint is the ONLY form of keeping water from getting behind the panels. There is an air/weather barrier on glass-mat sheathing as backup. So, now we are to the source mockup and field adhesion "pull" tests of the sealant and the PA has asked me to provide my recommendations for: 1. Sealant type, based on single bead condition compatible with GFRC, and backer rod, and perhaps a sealant primer; 2. In addition to adhesion testing, are there any static and dynamic tests for water infiltration, similar to curtain wall testing, in addition to AAMA 501.2 spray hose testing, that would be appropriate, perhaps AAMA 501.1, ASTM E 331, or E 1105? Also, is there an allowable/acceptable quantity of water penetration utilizing AAMA 501.1 or any of the other tests? Or would that be ANY water penetration? I can't find that. Also, would testing structural deflection of the panels also be appropriate for testing joints, maybe using ASTM E 330? I would think, yes. ILO hanging myself with my phone cord, or tossing my monitor out the window running out of the office screaming manically and joining a circus, can I ask the group to help out? Does anyone have experience with this predicament? What I did find helps, as follows, in terms of sequencing of tests for openings, but not sure if it applies to GFRC siding panels: 1. Static Water Penetration Test, then 2. Dynamic Water Penetration Test, then 3. Uniform Load Deflection Test, then 4. Retesting of Water Penetration. Michael Chusid, RA FCSI CCS Senior Member Username: michael_chusid Post Number: 369 Registered: 10-2003 Posted on Thursday, February 22, 2018 - 02:44 pm:    Don't do it. The lab testing does not replicate field installation conditions. On the other hand, we know nothing of the project. If it is located in the Mojave desert and will be used for only a few years to house non-critical functions, who cares if it leaks. Alternatively, if the joints are simple (For example, all vertical from coping to footing with without intersecting joints) consider compression seals instead of fluid-applied sealants. In my opinion (based on theory and not experience) they are easier to inspect -- simply measure the joint width after installation. Michael Chusid, RA FCSI CCS 1-818-219-4937 www.chusid.com www.buildingproduct.guru Louis Medcalf, FCSI, CCS Senior Member Username: louis_medcalf Post Number: 96 Registered: 11-2010 Posted on Thursday, February 22, 2018 - 04:35 pm:    Emseal makes a product called 'Backerseal' that acts as a backer rod to control depth of liquid-applied sealants, but is itself a waterproof seal. Brett Scarfino (Unregistered Guest) Unregistered guest Posted on Friday, February 23, 2018 - 10:37 am:    Sealant manufacturer will usually recommend sealant, primer, and/or backer rod based on your specific substrates, precon testing, and/or review of project details. I've worked with GFRC a few times in the past, and both projects utilized Dow Corning 790 w/ custom colors, primerless. All blessed ahead of time, then verified on the mockup. Usually see AAMA 501.1 hose water and field static air/water infiltration (ASTM E783 and E1105 respectively). These protocols need test pressures and allowable air leakage limits...and perhaps enhanced definitions of water leakage (for example, AAMA 501.1 allows up to 1/2 Oz of water meeting certain criteria). Dynamic field testing is becoming more common as more labs carry portable wind generators...but you might check with labs in your area to see if they can offer. Having this is all specified ahead of time is a good idea... and not just in the glazing system(s) spec sections. Structural E330 tests are usually reserved for full lab mockups... not easy to conduct in the field / special planning needed. Brett Wilbur Member Username: bwilbur64 Post Number: 3 Registered: 02-2018 Posted on Wednesday, February 28, 2018 - 02:17 pm:    Thanks guys, I appreciate the feedback. Brett, good info on the correct testing. I may have over specified in my draft section, but I can edit for the final. I also specified GE Momentive SCS7000 Paintable Silicone, I think similar to the Dow 790. But, I did specify the Emseal Backerseal ILO closed-cell poly as an alternative. I hope they will go that way, just so I can sleep at night. Jerome J. Lazar, RA, CCS, CSI, NCARB Senior Member Username: lazarcitec Post Number: 1859 Registered: 05-2003 Posted on Wednesday, February 28, 2018 - 04:26 pm:    Brett, Dow 790 is now Dowsil 790, check the website www.consumer.dow.com Brett Scarfino (Unregistered Guest) Unregistered guest Posted on Wednesday, February 28, 2018 - 05:55 pm:    Jerome - Thanks, I knew it was coming at some point and was hopeful they wouldn't change the familiar numbering scheme. Need to update along with Roxul who I discovered is now Rockwool as of Jan 8. Jerome J. Lazar, RA, CCS, CSI, NCARB Senior Member Username: lazarcitec Post Number: 1860 Registered: 05-2003 Posted on Wednesday, February 28, 2018 - 06:10 pm:    Yes Roxul is no more, Colin does an excellent job of keeping us informed, so be sure to check the 4specs.com website for company changes. For some reason many of my clients would rather hear about these changes from me, rather than 4specs.com. I temporarily list the previous company name under the list of approved manufacturers Rockwool (formerly Roxul), Inc. www.rockwool.com .