[Strawbale] Re: round houses

["Rob Tom" <ArchiLogic@yahoo...>]

On Tue, 20 Mar 2007 06:13:16 -0400, Rikki  Nitzkin  
<rikkinitzkin@earthlink...> wrote:

> Can anyone send me photos/advice about building round roof/base plates  
> for loadbearing, round SB houses?

Rikki and You're-o-pee'in RoundHeads;

Assuming that you wouldn't try to make a wall-width, monolithic  
cast-in-place concrete beam that would be nothing more than a massive  
thermal bridge (but would be the easiest to fabricate),  box beams using  
laminations of 19mm thick (or similar) lumber (staggering the joints from  
one lamination to the next, as well as offsetting the  joints in the web  
material and adding shear plates at those joints) to construct the cords  
would be a good choice-- "good" in the sense that box beams would consume  
a minimum of lumber while providing the necessary strength and insulative  
properties consistent with the SB walls on which they sit.

The sizing of the chords and webs would need to be determined for the  
specific loading conditions.

If bending/laminating 19mm thick lumber into curves is deemed to be too  
challenging, then making the beam an octagon (or similar polygon) would do  
the trick but wouldn't be a continuous (and hence stronger) beam as in the  
case of the former.

The joints would be re-inforced most easily with the use of steel bands at  
the outer face to provide the tension to resist outward thrust (assuming  
no centre pole or collar ties) and sheet steel or sheet lumber gussets  
across both faces of the joints to resist shear.


=== * ===
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
--
=== * ===
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