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The Flying Gable
Here is an arbor with a sleek yet elegant design. But it is the end
result of numerous engineering and design considerations:
- The patio to be shaded lies in the corner of an L-shaped house.
- The main entry onto the patio from inside the house is tucked way back
into the crook of the L under the eaves.
- The house roof-overhang is a large one: 3 feet all around.
- The roof's gutters are only 8 feet above the patio, about the average
indoor ceiling height, making it impossible to attach the arbor to the
walls of the house.
- The morning sun poses no problems, the mid day sun is tolerable
because of nearby tall trees, but the late afternoon and evening sun are
blinding, with the sun penetrating all the doors and windows bordering the
patio.
- The landscaping layout was geared to the terrain with no thought given
to a patio cover beforehand.
- The patio is not only vast but also irregular both along the house as
well as along the retaining wall.
Now, if a
rectangular arbor were fit into the rectangular corner, with no possibility
for attachment to the house walls, then there would be posts all along the
walls 3½ feet out, that is, at gutters' edge. So a diagonal orientation was
used for the arbor. By using a gabled corridor with attached wings, the rear
main entrance to the house was emphasized instead of being buried in the
background.
No matter what the canopy design,
at least six posts would be required to support such a large canopy. By
using four posts to support the gabled portion a quarter of the way in, and
one post to balance each wing, the minimum number of posts were used, only
two of which are within six feet of the house.
 And
it avoids looking like a box !
Next, the diagonal orientation pointed the arbor directly at the sunset, so
all the lath work had to be run at a right angle to the diagonal to block
the sun from the door and windows.
Further, because the arbor is
detached and is so snuggly fit to the eaves along the wings, the arbor had
to be made absolutely rigid. Otherwise any vibration from wind or seismic
movement would induce a collision with the house's roof and transmit the
vibration to the house's interior.
In engineering, the element of stability is the triangle. The detail-photos
show how triangles were used in the gable and wings. But not obvious is a
triangular configuration of cables connecting the ends of one of the lower
beams to the center of the ridge beam atop the gable. (To see it, click on
the small photo up top that's at the bottom-right of the artwork.) This
prevents the ridge beam from acting like a regatta boat where the oars are
the rafters' counterpart here.
Given that the canopy be rigid, the posts also needed to be made rigid.
This was done by setting hefty pressure-treated timbers four feet deep in wet concrete 16
inches in diameter. The columns are merely ornamental and are slipped over
the pressure-treated timbers for appearance.
Actual testing demonstrated that the ridge beam would move a mere ¼ inch
with a 300 lb impact to the ridge beam. With the separation between the arbor and the gutters
being a uniform three inches, the arbor is adequately robust for its close
proximity to the house.
Finally the open gable allows the rear entrance, set back as it is under
three feet of roof, to receive at least as much light as it did before. The
open rear gable provides a 3D triangular, shaded, open skyward space. Also,
on bright
sunny days, the light reflected by the canopy into the underside actually
brightens all the areas under the eaves.
The final product is functional, safe and complimentary of the
pre-existing elements. Now one might have an appreciation of what goes into
design work. And in a situation like this, it is a crucial element of the
construction.
People with tight budgets, sticky
purses and no engineering background usually try to circumvent this
preliminary design process. And what they get is a klutzy or
under-dimensioned structure -- others can tell that something's just not
kosher just
by looking at it, but they just can't place their finger on it. So you'll
never be told by your friends about it; they'll just ignore it.
Note this well:
The intellectual property is no less tangible than the physical structure !
And it's well worth the small expense relative to
the large amount of money going into such a structure. So be advised not to
short-change yourself on the design and engineering aspects of your project.
Ignore that and your project will elicit the same response. Ho hum.
See those hanging candelabras? That's an innovative touch by the owners.
The lights are real candles. See that inverted glass cone as the center
piece of the candelabras? Just guess what the owners put in there when
they're having an outdoor BBQ after sunset: Goldfish ! ! ! Now
that's a hint of California Dreamin'.
Over the years, this arbor has been
reproduced under license several times by others around the US and one has
even been built in Montreal Canada. It's a classic design perfect for a
canopy over a large inside corner. It's not simple to do and there are
numerous details not revealed here which must be addressed to (1) get it
right (straight, level, plumb and properly dimensioned) and (2) to keep it
from contracting dry-rot, acquiring weather-blemishes or coming apart at the
seams in the future.
Do you see any fasteners whatsoever in
that hollow PVC 2x4 sloped and horizontal lath? Oh, you didn't know it was
hollow PVC?
Contact me for a limited license,
building plans and detailed written instructions if you wish to have one
built outside California. I personally handle all the in-state construction
projects.
Click here for a
Copyright Notice
and your responsibility after it has been completed. See my Rewards Program
for rewarding those reporting a copyright infringer by
clicking here.
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