"dg" wrote in message
oups.com...
I am really looking at this from a more fundamental viewpoint.

If we take foundations as an example, typically the BCOs in my area
want 600 wide and a 1000 depth. Even if all the similar properties in
all directions have foundations at 450 x 600 deep. OK, there may be
differing ground conditions, but what I am saying is .... if 500
houses around a particular job have absolutely no probelms with a
particular foundation width and depth, then why can't this be proof
enough that that particular foundation design can support a structure
of similar construction, size and loadings?

With openings, I can see numerous instances of openings near external
corners, and slender piers between openings, and these have been in
place for decades, with no distress tho the building. But if I want to
do something similar I have to prove this by [theoretical]
calculations. Why can't I prove this by actual demonstration of an
instance previously built and with no problems?

Computer models and scale models are constructed to test designs. So
why can't existing buildings be used as models to prove that a design
works (in a given set of circumstances) ?

dg


How do you know the design has worked , how do you know that the building
has had no remedial works performed on that section
Are you aware construction techniques have changed so that roof weight
distribution is now different on many new buildings
(purling are no longer in general use domestically all the load is placed on
the wall plates now through trussed system roofing)