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November/December 1996
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Division 4 - MASONRY
Jungle Architecture
Congress for the New Urbanism
Second Ward Association Builds on AIA and
City Planning's Workshop Goals
Division 4 - MASONRY
by Rip Case, CSIW.R. Grace, Masonry
Products Division
This is the first in a series of articles
discussing various aspects of designing and building with
masonry. Future topics will include thru-wall flashing, efflorescence control,
cleaning masonry walls, and the use of integral water-repellents
in concrete masonry units (CMU).
ASHRAE 90.1
ASHRAE 90.1 is a standard created by the American Society
of Heating, Refrigeration and Air-Conditioning Engineers to
determine the U-Values in non-residential construction. The
standard addresses and sets minimum requirements for energy
efficient design and has been adopted by a number of states
throughout the country. ASHRAE takes many factors into
consideration when determining the energy values required for
efficient performance, such as; geographic location, heating
and/or cooling requirements, glazing, overhangs, building
positioning and construction materials. The standardÃs goal
is to achieve optimum performance at the lowest cost. In many
cases, the R-Value needed may not be as high as traditionally thought.
Computer based programs are available to help you and your
engineer determine the actual values needed for your desired
performance. In many cases, the heating and/or cooling needs
can be reduced when completing this analysis.
THERMAL-MASS
ASHRAE also addresses the ability of the construction
materials to store and release heat through their thermal
mass capacity. Thermal mass is defined as materials with mass
heat capacity and surface area capable of affecting building loads
by storing and releasing heat as the interior and exterior
temperatures fluctuate. Masonry materials have excellent
thermal mass capacity and slow down the heat loss through a building,
decreasing both heating and cooling loads. This material advantage
allows the designer to insulate at a lower level with masonry when compared
with alternative building materials without thermal mass capabilities. Comparing
standard R-Values of construction materials does not necessarily indicate
the thermal performance if thermal mass characteristics are not
considered.
Thermal performance of Masonry Walls are addressed in NCMA
(National Concrete Masonry Association) TEK Notes 6-1A (1995)
for Multi-Wythe CMU Walls and TEK Note 6-2A (1996) for
Single-Wythe CMU Walls.
INSULATION IN SINGLE-WYTHE CONSTRUCTION
There is a comfort level with the R-Values and performance
of board and batt insulations in cavity wall and interior
finish masonry construction, but what if your budget or
application dictates a single-wythe structure with a hard
interior finish? You may even believe that you cannot meet
your thermal requirements with this type of construction.
Again, the thermal mass of the material should be the determining factor
as opposed to the stated R-Value of the individual masonry units.
There are a number of insulation choices for single-wythe
CMU construction, such as; polystyrene inserts, loose fill or
specialty reduced web insulated units. Based on the thermal
mass capacity of the masonry and considering the other factors
that determine heating/cooling loads, you may easily achieve
the thermal performance your client desires.
When determining the thermal needs for CMU single-wythe
construction, consider the following factors:
Does the interior allow for finish
and insulation, or will the cores(or cavity) need to be
insulated?
The density of the units is the
major factor in the thermal capacity. Cubic foot density
of the block material effects fire ratings, STC, R-Values
and U-Values.
ALWAYS BUT ALWAYS request data
reflecting R-values for the density of the CMU you intend
to use on your job.
When comparing the performance of
various insulation types within the wall, be sure that
the comparison of unit densities is equivalent.
A wall with hard surface
requirements on both sides may be insulated to provide all
the energy efficiency and structural integrity you
require.
Determine the percentage of the
wall area to be grouted. Typically in the south, walls
are grouted on 48îo.c. which represents 17% of the wall
area to be insulated.(See TEK Note 6-2A). Areas of the
country subject to seismic and structural codes may
require different grout spacing.
Does your choice of insulation
allow it to remain in the grouted cells without affecting
the structural integrity?
What effect will the R-value
reduction in partially or fully grouted walls have on the
owners energy cost?
Is the insulation drainable? Does
it allow moisture which inadvertently enters the wall to
be collected and directed to the exterior?
REMEMBER anything which interferes
with the process of water collection and direction of the
water to the outside of the building is contrary to the principles
of good masonry design.
Is the insulation absorbent? How
will this effect the thermal performance?
Will damage result if insulation
traps water and freezes?
Has insulation shrinkage been taken
into account when calculating R-values?
Quality Assurance?
How will the designer verify that
the insulation has actually been installed in sufficient
quantity to assure the values
indicated?
Who would bear the expense of
needed remedial work if an infra-red inspection indicated
insufficient quantity of insulation?
Many of the previous issues are easily overcome
through proper masonry design, detailing and specification.
Thoughtfully consider the building use, the location and the
desired performance before determining the thermal value needed. Compare
equivalency of the insulation productsÃperformance in building materials
of like density and thermal mass capacity.
Do not be afraid to explore alternative building
materials. Their thermal performance may be better than you think.
Consider the use of masonry with its thermal mass capacity,
fire-resistance, beauty and durability for life cycle cost effectiveness.
Jungle Architecture
The International Committee had a rare treat at the
June meeting. Tom Robson, AIA, of HOK/Houston, called on the
Dallas office principal in charge of design William Paul
Lacey, AIA, to do the presentation. The topic was "Cash
vs Culture." We took a look at architecture in the
jungles of Indonesia. We frequently evaluate architectural
design as an origin of the "Primitive Hut" or as adhering
to Greek proportions. This presentation spanned the full
spectrum between the two, then challenged us to consider the
end results of our designs.
In the Irian Jara, West New Guinea jungles, where the
natives have only recently stopped their custom of cannibalism,
a Sheraton Inn at Timika was commissioned by Freeport,
Indonesia. This HOK/LBI Associates project presented
challenges that one would expect from a jungle setting. But
the usual mosquitoes, snakes, and frogs were overshadowed by
such jungle inhabitants as moths with a wing span of 8 to 10 inches.
The natives were not necessarily inhospitable, but the design
crews were constantly reminded of their own human vulnerability.
To preserve the native culture and artifacts of the
region, an Asmat Museum of Art was part of the Sheraton Inn
design. The natives were approached to contribute artifacts,
not only as design elements for the Inn, but also as
authentic tribal designs. Additionally, many of the
furnishings were produced by native Indonesian craftsmen. The
Inn for Freeport guests and executives was designed to
provide protection from the jungle elements while being
unobtrusively placed in the rain forest. Availability of local
materials played a deciding factor in much of the design.
This International Committee presentation was certainly
thought provoking and bordered on creating an element of fear
for design professionals that trek into these jungles without
a "Tarzan" as a protector.
Bonnie Boudreaux, Associate AIA, Committee Chair
Congress for the New Urbanism
CNU IVThe neo-traditional movement in the U.S.A.
Charleston, South Carolina
May 3-5, 1996
The Congress for the New Urbanism IV,
affectionately called "CNU IV" gathered architects,
planners, developers and public officials from all across the U.S.,
and surprising numbers from abroad, for a three day "Congress"
in one of America's most livable small cities, Charleston,
South Carolina, May 3-5, 1996.
This was a most interesting and "livable" design
conference, many of which tend to be a competitive tedious, chest
thumping social event, rather than an educational assembly of
dedicated goal-oriented professionals earnestly working to
improve their knowledge and that of their colleagues. There
was clearly a spirit of collegiality at this gathering. A lot
of interesting information was exchanged, ranging from the economics
of transit oriented development to architectural guidelines
for successful mixed-use neighborhoods.
CNU was founded four years ago by Andres Duany and his
wife Elizabeth Plater-Zyberk, architects and planners of
Miami, Florida, best known for their Seaside project. CNU
started as a small invitation only group of dedicated believers in
neo-traditional planning and architecture. Peter Calthorpe
and Daniel Solomon of California were early apostles. Two
years ago, Peter Katz, the moderator of CNU IV, published a
highly informative, popular, well illustrated book, The New Urbanism
(Princeton University Press, 1993).
As stated in their charter (adopted at the conference),
"The CNU stands for the revitalization of the inner city and
reformation of the American Suburb within an integrated
regional structure. The Congress believes that the PHYSICAL COHERENCE
of communities is an essential component of their social and economic
well being. It sees the decay of the inner city, the
explosion of the formless, auto-dominated suburb, the displacement
of agriculture and the degradation of the environment as
interlinked problems of public policy and design ethics. The
Congress recognizes the enormous complexity of reordering the framework
of policy and practice that has produced our dysfunctional
and debilitating patterns of growth."
There were impressive speakers, particularly Mayor Joseph
Riley of Charleston (a politician of extraordinary accomplishments
in both design and social spheres of his city), British
architect Leon Krier (an inspiring true believer and
theoretician, railing against the failures of the modern
movement), the Senior Vice President of Equitable Life
Insurance Company (who declared that suburban sprawl is bad economics) Andres
Duany, and HUD Secretary Henry Cisneros, who also confessed
to being a believer and is implementing New Urbanism design
policies within HUD, especially as it relates to public
housing.
My friend Anne Bohnn and I left the conference inspired,
informed and optimistic about the real impact that this young
movement will have on the ailing physical face of our
country. There are important projects, besides Seaside, which
serve as cogent examples for skeptical developers, bankers
and municipal officials - notably Kentlands outside of
Washington D.C., Harbortowne in Memphis, TN, and Laguna West
in Sacramento, CA, as well as important projects in Seattle, Portland, Norfolk,
Cleveland, Cincinnati, and Dallas. Celebration, Disney's burgeoning
new town in Orlando should convince a lot of people. In all
these projects pedestrian oriented, strong neighborhood
principals are being rigidly and successfully applied.
There is a reason to hope, perhaps, that the pervasive
ugliness, congestion, foul air and down-right inconvenience
of our cities and suburbs and the desecration of the once
revered "public realm" is not the only choice of
the legacy for our children. In short, we have really messed
up our built environment; but perhaps it can be "saved."
A more aggressive "design ethos" on the part of
architects and planners is in order.
CNU V will be in Toronto next Spring with an emphasis on
transportation systems which create a more humane
environment. It will be generally open to the public. Maybe
we can get a few influential Houstonians to attend?
Peter Brown, AIA
Second Ward Association Builds on AIA and City
Planning's Workshop Goals
The Second Ward Association is acting on the
strategies of "changing perception" and
"improving mobility." These key goals where some of
many set by the AIA/Urban Design Committee and Houston Long Range
Planning during a Community Workshop held last November at
Ripley House, a community center located in the Second Ward.
Addressing the issue of mobility, the Second Ward
Association and Houston Metro are negotiating the addition of
a lunch-time bus shuttle between the Courthouse District and
the historic neighborhood. Metro is also looking into setting
aside funds for the renovation of the Franklin Street Tunnel
which stands as one of the Ward's key gateways to the old
neighborhood.. Preliminary efforts are to be cosmetic at best
but will go far to improve the all important first impressions
as one enters into the neighborhood.
The shuttle is tentatively being called the "Green
Line." The name builds on the successful Red, White and Blue
shuttle lines which traverse the downtown area. The new line
will run from the Courthouse, down Franklin Street, through
the Franklin Street Tunnel and on to Navigation. It will stop
at the area's numerous restaurants. Neighborhood
Restaurateurs are planning to provide lunch specials and
buffet style dining for patrons pressed for time. There is
also talk of special meal discounts for "bus patrons
only."
The Second Ward Association's continued success in turning
around its neighborhood also hinges on sustained effort by
the neighborhood committee members and participating
professionals from the public and private sector. Some of participants
in this recent Metro effort include Paul Mesa, Chairman of
the Second Ward Economic Development Committee; Houston's
Assistant Director of Long Range Planning, Patsy Ricon-Kallman;
staff planner, Karen Orr; and a growing number of individuals
from the architectural, planning, real estate and legal community.
Progress Report: The Green Line "Lunchtime
Express" has been approved and Metro has given top
priority to the widening and refurbishing of the Franklin Street Tunnel.
Dan Searight, AIA
Searight Architects, Inc.
Member of AIA/Urban Design Committee and
Second Ward, Beautify Navigation Committee
Copyright©1996 AIA Houston Chapter
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