[GSBN] Fwd: temp & humidity swing reductions with earthen materials

[John Straube]

I have to chime in here. The experiments are interesting and useful, but they do not show that adobe or earth plasters have some magical properties.
The tests do not correct for the superior thermal insulating capacity of adobe or the very high reflectivity or lime plaster. These two factors may be sufficient to completely explain performance. Also, the airtightness/leakiness of the two test huts has not been reported, and this can change the results tremendously.
I am strong beleiver in these types of test hut studies, but they take some hard work to be able to compare and thus learn things from. This study does not do enough to allow us to properly compare.
We can say, a CMU hut will underform an adobe hut. But we knew this already just from R-value. An 8" CMU will have an R-value of under 2, around 1.8, whereas an 8" adobe is likely closer to R2.5.  That is a 25% difference. At these low R-values, even small changes make a big difference. I also know I would not want either one without additional insulation in most  climates.

On 2010-06-24, at 9:56 PM, ejgeorge at riseup.net wrote:

> Hi all,
> 
> Thought this might make for some interesting reading - several papers recently forwarded to me on use of earthen materials for indoor relative humidity control and temperature buffering.
> 
> "Tim Padfield Museum Document" is a Danish study that analyzes the suitability of using lime and clay plasters for maintaining RH levels in museum (or similar settings).
> 
> "AdobeUSA2009 Tim White Final Paper" examines "the effects earthern plaster and exterior lime stucco have on controlling humidity and temperature in building envelopes."
> 
> "Adobe and latent heat a critical component for newsletter" summarizes a series of six studies comparing thermal comfort differences of adobe vs. cinder block buildings.
> 
> I've only recently ever heard Ceasar's Stucco - anyone out there familiar with them?
> http://www.romanstucco.com/
> 
> 
> ej
> 
> 
> ---original message-----
> 
> 
> I have attached some papers for you on reduction in temperature and humidity
> swings in building envelopes.  There are some amazing things taking place
> with traditional Earthen and Lime plasters.  It just so happens that they
> work great with straw bale buildings.
> 
> Enjoy the reading,
> 
> 
> 
> Tim White
> 
> Working Engineer, CEO
> 
> Caesars Stucco, LLC
> 
> 2388 Camino Capitan #4
> 
> Santa Fe, NM 87505
> 
> 970-946-1204
> 
> 
> <Tim Padfield Museum Document.pdf><AdobeUSA09 Tim White final paper.pdf><ADOBE AND LATENT HEAT A CRITICAL CONNECTION FOR NEWSLETTER.pdf>_______________________________________________
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Dr John Straube, P.Eng.
Associate Professor
University of Waterloo
Dept of Civil Eng. & School of Architecture
www.buildingscience.com