| Author |
Message |
Brian E. Trimble, CDT
Senior Member
Username: brian_e_trimble_cdt
Post Number: 81
Registered: 08-2005
| | Posted on Thursday, May 12, 2016 - 10:42 am: |    |
I am curious if anyone knows the marketshare of the different types of insulation used in masonry cavity walls/brick veneer walls. I get the sense that most walls use XPS, but wonder how much NFPA 285 has forced people to mineral wool insulation. I am not looking for a definitive number, just a sense. |
Nathan Woods, CSI, CCCA, LEED AP
Senior Member
Username: nwoods
Post Number: 694
Registered: 08-2005
| | Posted on Thursday, May 12, 2016 - 11:26 am: | |
100% of the new construction bldgs my office has done in the past 3 years have all implemented mineral wool insulation for the CI component of the rain screens |
anon (Unregistered Guest)
Unregistered guest
| | Posted on Thursday, May 12, 2016 - 11:38 am: | |
i work for a large architecture firm in the US. We have switched almost completely to rock/slag wool for C.I. at opaque cladding in exterior walls due to NFPA 285 testing requirements. In our office, XPS is used only for buildings/assemblies that do not trigger NFPA 285 testing requirements.
We have also started using insulated metal backup panel systems - which have been NFPA 285 tested for several cladding materials. |
Greta Eckhardt
Senior Member
Username: gretaeckhardt
Post Number: 41
Registered: 08-2013
| | Posted on Friday, May 13, 2016 - 10:38 am: | |
Construction assemblies with brick masonry cladding and extruded polystyrene insulation have been tested and passed NFPA 285, with specific requirements for window perimeter detailing. XPS offers an R-value of 5 per inch, whereas mineral wool offers only 4.2 to 4.3 per inch. For that reason I would recommend XPS behind brick, and have specified it many times in the past, since it requires less thickness to achieve the necessary thermal performance.
Behind other types of rainscreen cladding, mineral wool is needed to pass NFPA 285, so if we have a wall that has more than one type of cladding, we would typically use mineral wool even behind the brick, for continuity - and this happens to be the case for most projects at the firm where I now work.
Another consideration is that mineral wool may be preferred because of sustainable design concerns, such as the high global warming potential of XPS blowing agents and flame retardants needed for XPS. |
Curt Norton, CSI, CCS
Senior Member
Username: curtn
Post Number: 238
Registered: 06-2002
| | Posted on Friday, May 13, 2016 - 12:56 pm: | |
We have mostly switched to ISO-ci. With attention to window details, it has passed NFPA 285 testing for most cladding materials that can pass the test. EIFS is a separate story, but it will pass as well with the right system. |
Ronald L. Geren, FCSI, AIA, CCS, CCCA, SCIP
Senior Member
Username: specman
Post Number: 1401
Registered: 03-2003
| | Posted on Friday, May 13, 2016 - 01:50 pm: | |
EIFS is required to pass NFPA 285 as a condition of compliance with ASTM E 2568, which is required per IBC Section 1408.2 (2012 edition), whether or not a building is exempted from NFPA 285 testing per IBC Section 2603.5.
Take note that NFPA 285 is an assembly test and not a component test. Just because a product says they "pass" NFPA 285 testing does not mean it is acceptable for use in every type of wall assembly--the wall assembly must match the tested assembly.
Ron Geren, FCSI, AIA, CCS, CCCA, SCIP
www.specsandcodes.com |
Brett Scarfino (Unregistered Guest)
Unregistered guest
| | Posted on Friday, May 13, 2016 - 02:18 pm: | |
Predominantly Roxul or Thermafiber, regardless of exterior cladding. More Architect clients are starting with this approach, vs. a few years ago.
On a limited basis and for smaller projects, I see plastic alternatives specified. For these projects, the recent trend seems to be polyiso vs. XPS, inspite of polyiso's sensitivity to moisture. Perhaps a result of NFPA 285 tests - Polyiso chars in place; XPS melts at a fairly low temperature. Undesirable either way, but the later is far more concerning. |
Dewayne Dean
Senior Member
Username: ddean
Post Number: 57
Registered: 02-2016
| | Posted on Tuesday, June 21, 2016 - 12:00 pm: | |
A few people in our firm have the mindset that Rock Wool is an outdated product that is subject to mold and deterioration. They claim that over time there will be nothing left in the cavity.
Any evidence of this ? |
Nathan Woods, CSI, CCCA, LEED AP
Senior Member
Username: nwoods
Post Number: 695
Registered: 08-2005
| | Posted on Tuesday, June 21, 2016 - 12:13 pm: | |
I have the opposite opinion, mineral wool based semi-rigid insulation is naturally water repellent and not subject to mold or determination. Thermafiber's RainBarrier insulation is a good product, and they have a pretty convincing youtube video available here: https://youtu.be/UIXjWWlcwdc |
Dewayne Dean
Senior Member
Username: ddean
Post Number: 58
Registered: 02-2016
| | Posted on Tuesday, June 21, 2016 - 12:33 pm: | |
Thanks Nathan  |
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