SB: Re: laying bales

[Derek Roff <derek@unm.edu>]

I'd start by getting a copy of Build it with Bales 2, and get your friends 
to buy one too.  This book discusses the options and reasons at a length 
and depth that is difficult to match on this list.  Plus the graphics are 
way better.

> 1.  If two pieces were used, what (if anything) could lay
>     in between the pieces of wood?  We were thinking blueboard,
>     but am interested in hearing other perspectives?

Filling the space with pea gravel is recommended by many.  This allows for 
potential drainage of moisture from above, and provides a capillary break, 
slowing moisture rising from below.  Some recommend weep holes in the outer 
bottom plate.

> 3.  Last question - Locust is considered to be extremely resistant
>     to rot - could this mean that it resist the wicking of water
>     into its' pores because it is such a hard wood?  If this is
>     so, couldn't it be possible that the locust itself would be
>     a good enough moisture barrier - even when it has not been
>     treated?

Some dense woods are rot resistant.  Some are not.  The same is true of 
medium and low density woods.  In general, dense woods absorb and release 
moisture more slowly than non-dense woods, but expansion rates are often 
higher.  This can lead to more warping and checking problems.  Treating 
wood with toxic chemicals like CCA doesn't have a large effect on moisture 
absorbtion.

All woods can absorb water equal to at least 30% of their oven dry weight. 
Most can absorb 70-200%, and commonly have this much water when cut green. 
Black locust is rot resistant, but will absorb and transport moisture.  No 
common construction wood should be considered a moisture barrier, as 
builders use the term.

Derek Roff  

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