Archive through March 01, 2011

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Author Message Dale Hurttgam, NCARB, AIA,LEED AP, CSI Senior Member Username: dwhurttgam Post Number: 75 Registered: 10-2005 Posted on Thursday, February 10, 2011 - 01:28 pm:    We have a project where a voluntary alternate was provided to use spray polyurethane foam insulation in the cavity of a brick veneer wall. As proposed, the spray would go directly on the face of the glass matt gypsum sheathing in lieu of the specified air/vapor barrier and rigid extruded polystyrene insulation. The Project Architect has reviewed all the technical data, and has not identified any potential problems or concerns. Has anyone had experience with this type of application? We are using Ferro (side of the stud attachment - brick tie system). Lynn Javoroski CSI CCS LEEDŽ AP SCIP Affiliate Senior Member Username: lynn_javoroski Post Number: 1194 Registered: 07-2002 Posted on Thursday, February 10, 2011 - 01:34 pm:    I'll be interested to read what others contribute. I, too, have had requests for this - another "better than sliced bread" situation? Wayne Yancey Senior Member Username: wayne_yancey Post Number: 425 Registered: 01-2008 Posted on Thursday, February 10, 2011 - 01:51 pm:    Dale, I would give this system a thumbs up. The top 3 continuos insulations are XPS, mineral wool, and closed-cell polyurethane. The Fero brick ties are also a good choice and I do not say that because I am from Alberta where they were invented. On 2nd thought, yes I do say that because I am from Alberta. The polyurethane will provide the thermal barrier and the air barrier and nicely fill in the voids and crevaces around penetrations and other wierd constructions. Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 372 Registered: 10-2007 Posted on Thursday, February 10, 2011 - 02:01 pm:    Does the cavity with the foam still allow for drainage of moisture and pressure equilazation? Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP Senior Member Username: specman Post Number: 924 Registered: 03-2003 Posted on Thursday, February 10, 2011 - 05:12 pm:    Depends on the installation, height of building, and if a sprinkler system is installed. Can it pass the NFPA 285 test per Section 2603.5.5 of the 2006 IBC (or similar section in other editions)? I suggest looking at the evaluation service report (if any) and see if the proposed installation complies with the report. Ron Geren, AIA, CSI, CCS, CCCA, SCIP www.specsandcodes.com John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 1295 Registered: 03-2002 Posted on Friday, February 11, 2011 - 12:11 pm:    Cavities are not filled, so the drainage principles are the same. These products serve as thermal, air, moisture and weather-resistant barriers so they can replace several products. I do think this is one of the best systems for exterior wall assemblies. It has been used in New England for years, and in Canada before that. Our typical wall assembly moved the thermal insulation outboard of the vapor retarder after the introduction of the air barrier code, and the spray applied is a natural follow up to rigid foam boards. There are NFPA 285 tests for using these products behind masonry, but this is a significant issue because of the way this test is done. It is for a single assembly, so alternatives, such as thicker insulation, don't necessarily meet the test. However, there are exceptions to the application of the NFPA test under particular conditions, and I think the ICC is looking at modifications to the code since it is a bit far-reaching. Note that if you're using spray foam behind composite metal panels, forget it. No one has tested that, but then again, very few have tested it with foam boards either. Some cautions with spray foam: Applicator skill is very important to get an even coating. We added comprehensive mock-up requirements to help control that. The foam will not stick to the surface of all manufacturers peel-and-stick flashings, so be sure to do the research as to whose flashing product will work. Has to do with the coating used on the surface of the polyethylene. Talk to the foam folks. There was one well-publicized case around here where the foam curled back at the perimeter of the installation. Foam shrinks as it cures (which is a fairly short time frame) putting stresses that can cause this curling. The solution is to detail the edges of the foam to butt into a more or less square return of something. This will help to restrain it. (It is hard to describe a detail verbally, so you'll have to take a leap of faith here, and talk to your foam rep.) Use a brick anchor section that puts the tie outside the face of the foam. The anchor can serve as a guide to the thickness of the foam. This also allows the tie section to move. Anchors must be installed before the foam. The foam may not adhere to certain metals, such as (I think it was) aluminum, without primer. Again, talk to the foam reps. As the manufacturers get more sophisticated in these applications, it will be an improved product. Unfortunately, the manufacture and distribution of foam is not conducive to the high quality technical sales and support. There are chemical manufacturers who make resins or blowing agents, and then there are the labeller/marketers who make the products. Some labeller/marketers are not very strong with R & D and tech support, but the chemical manufacturers don't really provide it. Others, such as BASF, do both well. So work hard at finding the right folks in your area. James M. Sandoz, AIA, CSI, CCS, LEED AP Senior Member Username: jsandoz Post Number: 83 Registered: 06-2005 Posted on Tuesday, February 15, 2011 - 09:22 am:    Great information, John. Thanks. I'm all enthused now about getting a knowledgeable rep into our office to give a presentation on spray foam insulation in cavity walls (or I could just have the other architects in the office read your post :-). Seriously, energy codes are pushing toward continuous insulation and it is important for architects to understand the finer points of installation whether they are creating drawing details or observing the installation. Brian E. Trimble, CDT Senior Member Username: brian_e_trimble_cdt Post Number: 38 Registered: 08-2005 Posted on Tuesday, February 15, 2011 - 06:06 pm:    Yes, codes are stressing the idea of continuous insulation and the cavity is a great place to locate it there. For the wall to still work as a drainage wall there should be a gap between the foam and the back of the brick veneer. This should be no less than one inch according to our (BIA's) recommendation (2" preferred). In some cases the foam may have to be trimmed to keep the cavity open. If you don't leave a gap how will the water drain down properly. Follow John's caution above about applicator skill. Mockups are a good way to test this out if it is fairly new to everyone on the project team. Tim Howarth, AIA, CCCA, LEED AP (Unregistered Guest) Unregistered guest Posted on Wednesday, February 16, 2011 - 03:37 pm:    I rejected this "voluntary alternate" because the material supplier could not substantiate compliance with NFPA 285 or IBC. As I understand it there is only one rigid insulation that has passed the NFPA testing. I would be very cautious with this. During review I consulted the AHJ for their input. That input provided the teeth for my rejection. Jim Sliff Senior Member Username: jim_sliff Post Number: 25 Registered: 08-2010 Posted on Wednesday, February 16, 2011 - 08:15 pm:    I have experience with spray polyurethane foam in roofing applications and years of experience with the type of application equipment used. Hopefully the comparisons will have some value. "Some cautions with spray foam: Applicator skill is very important to get an even coating. We added comprehensive mock-up requirements to help control that." IMO that's an excellent idea - but perhaps a bit too light. It would really depend on the extent of the mockup. SPF is applied with plural-component, heated spray equipment - material ratios vary but 1:1 is most common. The equipment is so far beyond the technology of conventional or airless spray equipment I'd compare it to a B2 vs a Piper Cub. Some applicators apply urethane and polyurea systems using the same equipment (or similar units, with each dedicated to a type of material to avoid contamination. Small cart-mounted spray systems (which require only standard outlet power and a portable air compressor) run $20-30 grand by the time a contractor buys backup parts, special tools, etc; trailer-mounted rigs carry drums of material, feed pumps, recirculation systems, large air compressors and often a 45KW generator - a $100k investment for the basics. One would think a contractor making that sort of investment would automatically "have a clue" - but it's not necessarily true. There are spray courses that contractors will send their lead applicators to that run a week (the Polyurea Development Association runs schools throughout the year) and although there are specific differences in technique the equipment is often identical, with foam application requiring specific training (but far less if a student is a certified polyurea applicator). Certain requirements are, to me, mandatory for the applicator of such systems: 1) A certified applicator (either foam or polyurea) on site during all application; 2) a minimum of 5-years experience on the part of the contractor in application of heated plural-component spray materials (again, the type isn't a s critical as experience with the equipment and knowing what to do when the inevitable problem erupts); 3) The applicator must own the equipment used. This one sounds odd, but there have been situations with potential bidders with experience - either with other companies or using rented/demo equipment- who can be clueless when there are problems. Almost every heated plural spray project will have problems - also, there will be situations on-site where an "out of spec" decision has to be made in 1-2 minutes due to the "set time" of some types of materials...so some flexibility needs to be built in (again, this requires prequalification of applicators). These variables also require an experienced inspector. Other requirements may be included but depend on the project (in deck coating, not foam, I'll often require that a minimum of 20,000 gallons of similar material have been applied within the previous 5 years.) With any plural/heated spray job (foam, polyurea, polyurethane) it's a good idea to have an inspector on the job who knows the ropes - many coating, insulation, waterproofing and building inspectors don't know enough about such systems or the method of application to know WHAT to test, or to comprehend that "normal" thickness gages may be useless. If they apply normal "coatings rules" to these materials they'll be way off-base. Sorry for bouncing around a bit - but foam and certain coatings have more similarities than differences when it comes to field quality control. One other observation - the manufacturers cannot help you put together a tight spec; some waterproofing consultants are familiar with the materials (both foam and urethane or polyurea membranes) but are not spec-oriented. What has often occurred is an experienced contractor will be called in to help develop the spec - and he'll also be on the bid list. It's been kind of unavoidable, but more and more consultants are coming into play who know the realities - that should put things into a more normal control system. Sorry if I was a little off-topic, but I hope the similarities are apparent enough to put things in context. John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 1302 Registered: 03-2002 Posted on Tuesday, March 01, 2011 - 11:05 am:    I found in my research with the manufacturers, the industry associations, and applicators that there is pretty much a divide between roofing applications and wall applications. Manufacturers may make both products, but industry associations don't really support both and applicators seem to do one or the other. Of course, the spray foam roofing industry is quite a bit older than the spray foam wall industry and this may be part of the reason.