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Green Building Discussion
Topic: Insulating Cement-Masonry Blocks
Discussion Participants:
- Bion Howard introduces a new CMU
- Marc Rosenbaum has some questions
- Andrea Warchaizer asks about Sparfil
- Terry Brennan with a good Sparfil story
- Bion Howard on Sparfil
- Norbert Senf on Sparfil
- Bion Howard on testing methods
- Marc Rosenabaum on Integra
All postings are the opinion of the writer, and BuildingGreen can take no responsibility for their accuracy or appropriateness.
Bion Howard introduces a new CMU
From: Bion Howard
Sent: Monday, November 25, 1996 9:48 PM
>>> R-10 to R12 lightweight _true_ structural CMU's <<<
Try contacting CBIS in West Brookfield MA. I just completed a thermal analysis of their HI-R unit, and it is pretty good for a true CMU with a two-web, interlaced polystyrene insert arrangement. Talk to Dave Nickerson, P.E. about it at (508) 867-4241 or outside Mass. 1-800-628-8476. Perhaps he can send you a copy of our report or their performance data tables that have just been revised. [CBIS is a division of W.R. Grace] ............................................................ Note: I do not have a beneficial interest in CBIS, but I did recently undertake a consulting contract with them.
Mr. Bion D. Howard bhoward2@sprynet.com (business) Building Environmental
ZowWatt@aol.com (fall-back) Science & Technology Voice:(301)627-2780
FAX:(301)627-4735
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Marc Rosenbaum has some questions
From: Marc J. Rosenbaum
Sent: Tuesday, November 26, 1996 7:54 AM
Hello Bion - I got the Hi-R literature when I was doing my search a while ago. I would be interested in the revised R values. As you may recall, I need a material with thermal resistance in both the horizontal and vertical directions. Thus far, the Hebel autoclaved aerated concrete seems to be the best solution.
Are the Hi-R R values tested or calculated? In a wall built of these units, do you have any idea of what temperature variation would be expected on the inside face of the block when the outdoor temperature was 32F or 0F? It seems to me that an issue is wall temperature because of potential mold growth on cold (therefore higher moisture content) surfaces.
Marc
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Andrea Warchaizer asks about Sparfil
From: AWarch@aol.com
Sent: Tuesday, November 26, 1996 6:31 PM
Marc et al, What do you know about Sparfil blocks, produced locally (to me) in Laconia, NH? This is a cmu with 60% of the aggregate replaced w/ EPS beads. EPS inserts in the block bring a 12" block to R-24. The blocks are dry-stacked and then surface bonded. I was all set to use these on a project, but now it seems that the local manufacturer is going off--line with the product while they reformulate the mix (and come out with their own brand of block). This is the only block I know of with the EPS mixed into the aggregate- is there anything else similar out there?
Andrea Warchaizer AWarch@aol.com
Terry Brennan with a good Sparfil story
From: TBren46501@aol.com
Sent: Wednesday, November 27, 1996 9:06 AM
Andrea,
I used Sparfil blocks years ago when they were only made in Canada. I liked them a lot. They were easy to use, sawed with a hand saw, made a strong wall and performed well thermally (I monitored interior surface temperature of the block and it was the same as the 2x10 rim joist with two inches of foil faced isocynanate foam board,1/2 inch sheathing, and air gap and 7/8 inch wood siding). Back then they didn't come with the foam inserts installed, so I filled the cores with peralite instead. I made a hopper that slid along the top of the wall so that it was easy to get the pearlite in. We put a stereo in the basement, put on Tocatta and Fugue in D minor, and cranked it up to warp twelve. The bass vibrated the heck out of the walls so we got a better fill (Ode to Joy might be better). If you start with a level and square first row it stacks quickly and easily. I haven't used it since I stopped the construction end of my business in 1985. The questions I'd have now are: is it still as precisely machined so that the blocks stack easily, how stable is it in a fire, is the styrene recycled, and what's the experience of those who have used it more recently? I don't know of any other products that use thermoplastic as the agregate. Good luck.
Terry Brennan
Bion Howard on Sparfil
From: Bion Howard
Sent: Wednesday, November 27, 1996 11:28 AM
These blocks were originally from a Canadian firm, and a good deal of research went into the invention. Their challenge was primarily related to getting their complex mix-design to work. Sparfill is licenced to US producers.
I do not believe their R-factor data however, and have done some independant ASHRAE isothermal planes calc's that come out MUCH lower. Ask them for full-wall test data from a calibrated (ASTM C976) hot box, and that data may contain more valid R-factor numbers.
"Reality" in R-factors claimed by the CM industry leaves alot to be desired, although their trade group NCMA, for whom I served as Energy Engineer back in the early '80s, has a pretty good "Manual of Facts on Concrete Masonry" and some data on embodied energy studies. (listed on their new web-site http://www.ncma.org )
NCMA has tended to err on the conservative side on their calculations and recommended approaches to block r-factors.
Hope this is helpful. ------------ Mr. Bion D. Howard, Principal Building Environmental Science & Technology P. O. Box 1007 Upper Marlboro, Maryland 20773 USA V:(301)627-2780 FAX:(301)627-4735
E-mail: bhoward2@sprynet.com (Alt.) ZowWatt@aol.com Website: http://www.nrg-builder.com
Norbert Senf on Sparfil
From: Norbert Senf
Sent: Wednesday, November 27, 1996 12:20 PM
Sparfil has been around for many years, and I haven't heard of any problems with it. I've seen it used as foundations for R-2000 houses, and I know a guy in Toronto who built a house with it about 15 years ago. A builder south of Ottawa used to distribute it (its been a few years since I've been in contact) and built a number of commercial buildings with it. It never caught on in a big way, perhaps because of the conservative attitude of the builders. It doesn't really require skilled labor, except to lay the first course. You don't want to hire an expensive mason, but carpenters may prefer to be doing something else, and laborers, well...
We've experimented with using the surface bonding compound ("Surewall" is one brand) directly onto type II (double density) white beadboard for homemade stress skin panels. Works great - I've got an 8ft x 8ft sliding door on my shop that weighs about 100 lbs.
Best....Norbert Senf -- ----- Norbert Senf email: mheat@mha-net.org Masonry Stove Builders mheat@hookup.net RR 5, Shawville website: http://mha-net.org/msb Quebec J0X 2Y0 fax: 819.647.6082 voice: 819.647.5092
Bion Howard on testing methods
From: Bion Howard
Sent: Wednesday, November 27, 1996 10:13 AM
BH sez -- Their new literature will use values based on a two-pronged approach. 1.) tested values for HI-R block were obtained from NAVLAP accredited facilities [n=3 tests]. 2.) ASHRAE isothermal planes method was used to calculate over a range of block density and thickness. Then the test data was used to fit an equation to the calculated R-factors so the very conservative ASHRAE calcs could be "verified." When approved Mr. Nickerson (see prev.) will possibly provide you with a copy of report. ..................... Note: no other insulated block producers now use this approach and their calculated literature R-factors (which in my estimation have often been overstated) have been analyzed and fitted to credible test results as does CBIS. CBIS r-factor data takes the mortar joints into account. .................... One unique feature of the CBIS units is the insulation overlaps the mortar joints, and the head joints interlock, so as to reduce heat and mass (moisture) transfer through the wall. In standard block mortar joints cost a 6% to 15% thermal bridging penalty (VanGeem ASHRAE Trans. 1985 no2)
> In a wall built of these units, do you have any idea of what temperature > variation would be expected on the inside face of the block when the outdoor > temperature was 32F or 0F?
BH - sez: 1-dim heat transfer problem (in a 3-D domain unfortunately since the block is a complex design) so take the delta-T, the R-factor (including any additional finish materials you might provide) over the material thickness and solve for surface temperature at the inside of the wall. Back of the envelope looks like about 56-58 degF for an ABOVE GRADE wall at OA 32F. The key issue would become what the indoor dew-point is. If the building had other mositure problems resulting in high indoor humidity it might be a problem, but during the heating season, indoor dew points are often in the 50F to 40F range.
Wall "sweating" might be more of a problem during summer months, but then the HI-R block if the indoor surface was an "architectrual" facing (split face, or split ribbed) the the concrete would have about a 2-week time constant to a step change in interior humidity levels. I first observed and reported on this effect in a passive solar home I monitored in the early '80s, located in Reston Virginia (paper in ASES 1983? proceedings -- Santa Fe...) where the occupants night-vented their all-block home, that had several hundred square feet of exposed architectural block inside. Despite outdoor RH in the 80% to 90% range at night indoors RH never much exceeded 50% according to sensor readings (semiconductor "humicaps" calibrated by Boeing Aerospace Div. subcontractor)
> potential mold growth on cold (therefore higher moisture content) surfaces.
A cold surface may not necessarily have "higher moisture content" unless there is no place (such as into the concrete matrix of a block) for it to dry to. A revealing excersize would be for you to get ahold of a copy of the NIST computer program called MOIST [Doug Burch, NIST, (301) 975-6433] and do some calculations related to surfaces wetting and drying at different temperatures.
Mr. Bion D. Howard, Principal Building Environmental Science & Technology P. O. Box 1007 Upper Marlboro, Maryland 20773 USA V:(301)627-2780 FAX:(301)627-4735 E-mail: bhoward2@sprynet.com (Alt.) ZowWatt@aol.com Website: http://www.nrg-builder.com
Marc Rosenabaum on Integra
From: Marc J. Rosenbaum
Sent: Friday, November 22, 1996 11:15 AM
Tom -
There is a local dealer for Integra, Foam-Tech, who is a foam-in-place insulator. They have used it in a small supermarket and it looked good to me. I agree that Integra looks better than the other options as far as R value is concerned. Foam-Tech has developed a zero ozone depletion polyisocyanurate foam which can be used with Integra.
I have not been able to locate ThermaLock - I think they must be out of business.
Marc
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