[Greenbuilding] Clay Brick

[Rob Tom]

On Mon, 09 Apr 2007 10:29:24 -0400, <JBurn48309 at aol.com> wrote:

> I am considering 3 types of building materials  for my home:
> (1) cob, (2) straw-bale or (3) clay brick.  Can anyone  tell me how  
> "green" clay brick construction is as far as how clay bricks are  made?

Joyce;

There is a chart listing embodied energies of and a discussion of how to  
help evaluate the relative "Green-ness" of,  various building materials in  
the "Measure of Sustainability" piece
at:

http://www.canadianarchitect.com/asf/perspectives_sustainibility/measures_of_sustainablity/measures_of_sustainablity_embodied.htm

but assuming that by "clay brick" you mean new, fired clay brick then it  
would be reasonably safe to say that it'd be the least Green of the three  
material types that you are considering, by virtue of it having the  
highest embodied energy (largely due to the energy-intense kiln-firing  
process to the and quite likely, highest operating energy (in terms of  
space heating/cooling energy ) over the course of the lifetime of the  
building since an uninsulated brick wall no matter how thick, do very  
little to keep heat and coolth in. The latter would apply to cob as well,  
albeit to a lesser extent.

Using the numbers from the chart mentioned above, then in the simplest  
terms of embodied energy of the materials (quickie arithmetic not checked  
):

========================================================
2-string STRAW BALE wall,
    incl. *2 - 1.5inch thick Portland cement plaster skins,
          *2x6 + 3/4" ply box beam, 2x4 sills.

    not incl.  plastering mesh/pins/misc hardware


EE = 193,662 Btus per lineal foot of 8 ft high wall.
=======================================================

Fired CLAY BRICK wall (metric modular units)

EE = 324,046 Btus per wythe per lineal foot of 8ft high wall
       (accounting for volume of mortar in wall not included)

Since an 8 ft high clay brick wall would have to be at least two wythes  
thick for stability, the above EE number would at the very least have to  
be doubled. In this part of the world ( Southern Ontario) it's not unusual  
to see older homes where the walls are triple-wythe brick.
===============================================================


If by "clay bricks" you meant sun-baked adobes, ahem... well, uh, I think  
I hear someone calling me.

-- 
=== * ===
Rob Tom
Kanata, Ontario, Canada
<A r c h i L o g i c   at  c h a f f y a h o o   dot   c a >
winnow the chaff from my edress in your reply