Cob: wattle & daub

[Darel Henman]

Jamei Tierney wrote:
> 
> This is not directly related to cob, but hopefully close enough.
> 
> Where I've been living for years, in wet lowland tropical areas of
> Hawai'i, cob structures don't seem appropriate.  There is no need here
> for insulation or thermal mass.
There is for humdity control, however.  For hundreds of years in Japan,
they have used dozoh, literally
meaning "earthen warehouse", for the storage of important books, foods,
grains, because of the temperature and humidity control that the
structures offered.  Most of Japan is more humid than Hawaii is, to my
recollection.  


>.....  Post & beam structures with wattle & daub walls could
> meet these specs.  
Yes, with sliding doors for wind to come through.

So here's my quest:
> 
> I'm looking for people who have experience in wattle & daub and natural
> plasters (especially in the tropics) who have the willingness and
> wherewithal to lead a wattle & daub / natural plaster workshop here on
> the island of Maui sometime in the next few months, November or December
> 2002, or possibly a little later.

The Japanese sakan (earthen and cement masons) are probably the best
around and are somewhat close to you.
Finding a sakan who understands English might be difficult though.

An alternative is that natural plaster workshops are conducted
relatively frequently in Japan.  It is a traditional and historical
materal for that's been used for hundreds of years.

> 
> -> The main project would be the plastering (interior and possibly also
> exterior) of a large multiple-octagon community center.  It was
> initially conceived as a post & beam structure (using locally-milled
> Eucalyptus wood) with wattle & daub walls. However, with the pressure of
> building codes, etc., it is presently being built with mostly standard
> materials and practices :(   The owner, though, has all along been very
> interested in modelling sustainable building practices and now wants to
> explore the use of natural plasters.  

> The interior surfaces are open stud walls, and the exterior surfaces are plywood sheeting.

Yuck!

> There is
> some openness to using lime plaster on the exterior.  The default plan is stucco.

Go with lime.  

> 
> -> Other projects might include doing wattle & daub walls on an existing
> post & beam structure.  The wattle could possibly be made of local
> bamboo.

You could also make a shita-ji window, which is leave a square or cirlce
or any shape for that matter, of the bamboo or reed lath exposed and not
plastered.

Havest bamboo from mid October to November when bamboo doesn't have as
much starch content in the culms.

Don't use nails that will rust to secure it to the posts.    The bamboo
should be tied together with a straw rope, hemp rope.  Though modern
plastic wrap things work, it unknown how long they will last, whereas
the natural ropes from torn down 80 year old buildings are still strong.

> 
> -> Some of the challenges with natural plasters here in Hawai'i:
>      * true clay may not exist on the islands, and may have to be
> imported (Bentonite drillers' clay is readily available in 100# bags)

If you have any rice paddies around there, try the mud in them.  It's
noted to be good, at least for the main islands of Japan.

>  * surfaces should not encourage the growth of mold or mildew in this hot & humid climate
Should be less a problem than concrete.

> -> Compensation would definitely be available for someone with the
> willingness and qualifications to lead such a workshop.

I can call the editor or somebody to try to find someone that you can
contact.

> I'm also personally very interested in doing earthen floors here.
> 
> By the way, cob structures could be very appropriate at higher
> elevations here (say, above 3000 ft), except that there probably isn't
> any native clay.
> 
> Blessings on the Journey of Natural Building!
> 
> Jamei

Darel