R Value of Adobe Walls

Weezbo

is the wall inquestion like 9 foot thick with bales of dry hay for insulation?

there is a greenie site where they have some formulas that they use to describe the building envelope...

it is like Mike says though as to where....

my computer crashed so i have no link to it..buh try out a search for Passive air heating systems....

Bob Sweet

Can't find any solid numbers on the r values of abobe walls, seems to be a lot of varying opinions.

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Mike T., Swampeast MO

Hard to consider adobe construction outside of the climate where it works--dry with temperatures that regularly go well above and well below the human "comfort zone" on a daily basis.

Every source I can find (both authorative and anecdotal) agrees that adobe constuction in a suitable climate provides exceptional "insulation".

It [appears] that the "best" modern adobe construction uses 1"-2" of rigid exterior insulation but the adobe itself probably isn't 24" or so thick as was common earlier.

GMcD

R-values of thermal mass

You cannot simply use the thermal R value of a thermal mass wall system for your estimates and calculations. There is a significant time response factor that has to be calculated and you'd need higher end software to calculate the actual thermal performance of the thermal mass walls. A rule of thumb is that it takes about 1.5 to 2 hours per inch of concrete for a thermal impulse to move, ergo, over 6" of concrete would provide a 12 hour response time for the thermal impulse to go through. So, in a climate with hot daytime outdoor temps, and cool night time temps, the thermal mass will absorb the daytime heat and release it at night, keeping the interior relatively stable.

Check out sites like www.enertia.com and do some google searches on "thermal mass" "thermal mass resistance", "thermal mass thermal properties" and variations on that theme. You cannot use a "factored" R value for simplified calculations since all thermal mass behaves differently in different temperature fluctuation regimes. I think that there are some calculations and software for ICF construction that might help, but they would not be a specific solution for your application.