[Strawbale] Bottom of wall detailing

[Rob Tom]

On Wed, 28 Mar 2007 18:49:08 -0400, N Leone <nlpub at roadrunner.com> wrote:

> On page 216, illustration 10D

> The graphic shows the top outside corner of the grade beam notched down  
> below the sill plate with the exterior plaster running down to that  
> point as well.  The note referencing that area says "The outer plaster  
> should sit on a shelf in the edge of the foundation below the sill  
> plates..."  So my question is:  Why?

> I know adding that notch to a poured grade beam might not be too hard,  
> but it's going to be a bit of a mess on a block stemwall such as mine.

Ned;

I haven't seen the sketch but even with stick-framed buildings the  
sheathing is typically lapped over the sill plate onto the foundation  
(with moisture barrier between of course) so as to cover the joint between  
the wood and the concrete to make it more difficult for air, critters and  
insects to get in.

Sometimes conscientious concrete formers will form a rebate into the  
concrete to accommodate that sheathing overlap even without your asking  
them to do so. The strip of wood that they use to form the rebate is set  
with a transit so that it provides them with an easy-to-see line to which  
the top of the concrete is poured. The strip is bevelled slightly on the  
bottom edge to facilitate drainage and make removal easier/reducing the  
chance of damaging still-green concrete.

With your proposed CMU stemwall, it would be a simple matter of clamping  
some 2x material onto your top course of block to serve as forms for a  
bond beam. Cover the 2x lumber with salvaged poly sheeting to serve as a  
form liner which will help to retain mixing water in the concrete to  
ensure full hydration of the cement and also to facilitate easy form  
removal and keeping the lumber clean for re-use (ie joists ? rafters ?).

And if you're really on your toes you will flip the sill plate 90 degrees  
and cast it into the face of the bond beam  (Just in case they didn't show  
that in the sketch).


=== * ===
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