[Greenbuilding] Roof slopes (was Re: Glass roofing)

Clarke Olsen colsen at fairpoint.net
Fri Aug 15 07:22:46 MDT 2014


A golden rectangle is one from which you can mark-off the square of an end, and be left with a smaller rectangle of identical proportion. If X & Y are the short and long sides, then X/Y = Y-X/X. Why don't these keyboards have a proper division symbol?
Clarke Olsen
clarkeolsendesign.com
373 route 203
Spencertown, NY 12165 
USA
518-392-4640
colsen at taconic.net




On Aug 14, 2014, at 6:08 PM, RT <ArchiLogic at yahoo.ca> wrote:

> On Thu, 14 Aug 2014 16:49:07 -0400, Clarke Olsen <colsen at fairpoint.net> wrote:
> 
>> True, the temples are shallower, but the diagonal of a golden rectangle (10 to 16.14....) is an ancient proportion used for
>> roofs in New England.
>> 
>> On Aug 14, 2014, at 3:28 PM, candtcampbell at juno.com wrote:
>> 
>>> I could have sworn that the pitch of a Greek pediment was something like 5.2 in 12.
>>> My favorite pitch is 7.5/12, aka 10 in 16.
> 
> 
> "7.5/12" and 10/16 are both Murrican (ie based on Imperial units) approximations of the diagonal of the Golden Rectangle -- close, but not perfect, Perfection being that which the Golden Mean is supposed to represent, derived by geometry rather than arithmetic.
> 
> Me ? I like 7/12 for roofs. 30 degrees. Easy to set up for cuts and joints. Not so steep that you slide off when walking around on it but steep enough that snow and rain don't accumulate on the outside and the inhabited roof volume is an interesting space  -- human scaled as opposed to slopes 12/12 or more which are better suited the Divine where much of the "soaring" space (or as one typo in a realtor's ad called it "sorrowing 20 foot ceilings") of the interior roof volume cannot be practically utilised.
> 
> Enginoids also like 30 degrees for roof slopes. Steeper than 30 degrees and live loading due to wind becomes a governing factor in the structural design --shallower than 30 degrees, gravity loads govern -- 30 degrees is the sweet spot between the two and is structurally very efficient.
> 
> -- 
> === * ===
> Rob Tom  .  .  . T60BOM
> Kanata, Ontario, Canada
> 
> A r c h i L o g i c  at  Y a h o o  dot C A
> (manually winnow the chaff from my edress if you hit "reply")
> 
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