about Sustainability

Building Envelopes: Greater Performance from Fewer Materials

A month or so ago I gave the kick-off talk at the Building Enclosure Council National Symposium, taking a very quick and dirty look at two kinds of history of building enclosures.  I have had a keen interest in building enclosures since I co-chaired the Technology Conference for the Association of Collegiate Schools of Architecture with Andrew Vernooy in 2001, which we titled “Building Skins:  Where Design and Technology Meet”.

One of the first projects I did in my career was an addition to a 19th century stone house in Austin that had 20-inch thick limestone walls.  I really admired that old house with its single-material walls and high thermal mass that actually performed beautifully without insulation or a vapor barrier.

As I have traveled I have admired a very long lineage of single-material walls. Ancient stone or brick walls acted as the structure, thermal barrier, and enclosure as well as interior and exterior finish.  I love the ruins of the ancient Hittite city of Hattusa in central Turkey where massive stone walls constituted virtually all construction—from dwellings and markets to gigantic ramparts.  Another great example is Machu Picchu in Peru, which is made almost entirely of carefully crafted stonework.

Ancient City of Hattusa, Turkey

Ancient City of Hattusa, Turkey

Stone walls, Hattusa

Stone walls, Hattusa

Machu Picchu, Peru

Machu Picchu, Peru

Centuries later, at the beginning of the 20th century, Cass Gilbert designed Battle Hall at UT Austin with very similar construction.  Its walls are just one thickness of stone all the way through, but they have performed very well both aesthetically and thermally for more than a century.  Even when air conditioning was added, Battle Hall’s high thermal mass has helped keep it temperate even during our hot Texas summers.

Battle Hall, UT Austin,  1910

Battle Hall, UT Austin, 1910

Battle Hall interior.  Photo (C) Nathan Sheppard

Battle Hall interior. Photo (C) Nathan Sheppard

There is a second history of walls that conceives of them as layers of various materials, each of which accomplishes a particular function.  Early versions of this can be seen in Roman buildings, like the Pantheon, that have a structural core faced with very different materials for the inside finish and the outside skin.

The Pantheon, Rome

The Pantheon, Rome

The Pantheon interior

The Pantheon interior

Over the last 20-30 years we have become very adept at making walls out of layers with many materials where each material is performing a separate role: one for structure, one for insulation, one for water-proofing, one for vapor barrier, another for interior finish, and another for exterior finish.  We are interested in getting the best performance out of each material with its own specific characteristics.  The coordination of so many materials may not be so great, with different  people doing each installation, often months apart in the building process.   A lot of glitches can happen at the intersection of those various materials, and the result is often not perfect.

Might we get equal or better performance out of fewer materials?  We have experimented with this idea in several projects we have done at Page, learning lessons from older single-material walls.  At the Torcasso residence, located in New Mexico, we used only rammed earth for some of the walls.  They are thick and solid and that single material provides everything needed: structure, vapor barrier, insulation, interior finish and exterior finish.

The Torcasso Residence, New Mexico.  Photo (C) Robert Reck

The Torcasso Residence, New Mexico. Photo (C) Robert Reck

Torcasso Residence interior, New Mexico.  Photo (C) Robert Reck

Torcasso Residence interior, New Mexico. Photo (C) Robert Reck

robert reck

In Austin, we designed a small office building for Wiss, Janney, Elstner Associates.  It features thick, unreinforced concrete walls, which serve as both the structure and the environmental barrier, and we used the walls’ thickness to significant thermal advantage.

casey dunn

Construction of Wiss, Janney, Elstner Building, Austin.

Construction of Wiss, Janney, Elstner Building, Austin.

I am not a building science nerd, and I certainly continue to be interested in walls made up of layers of materials capped by a rainscreen.  However, it also seems appropriate to explore another longstanding genre of wall construction that optimizes simplicity of construction and high thermal mass.



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Thinking about Building Technology, Buildings in Landscape, Campus Architecture, Contemporary Practices, Sustainability, Texas Architecture
Posted June 12, 2016

Houston’s Buffalo Bayou: Buildings in Parks

Buffalo Bayou, Houston   (c) Slyworks Photography

Buffalo Bayou  Houston (c) Slyworks Photography

I am a big fan of parks.  My local park in Austin is Zilker Park with its famous Barton Springs Pool. There is a beautiful 1940s bathhouse at the pool, designed by Dan Driscoll, an early Texas modernist architect.  I often stage my visits to the pool at times that will require a change of clothes just so I can enjoy the huge open air changing room and the very cool outdoor showers.  This blog topic is inspired by my experiences in parks and in designing buildings specifically for parks.

Decades ago, when I had my own firm, we did the Umlauf Sculpture Garden, also in Zilker Park and located just a short distance from Barton Springs Pool.  I recently participated in a series of tours for elementary school kids who came to visit the garden.  It was amazing to watch the eye-opening reaction of the kids exploring the four-acre park and its exhibits–taking a break from their regular school routine. We had our little talk on the huge porch that comprises half the space of the building at the Umlauf.  It has been a real treat to do many tours and lectures there through the years.  It’s an incredibly lively setting, and continues to thrive.

Above and below: The Umlauf Sculpture Garden, Austin

Above and below: The Umlauf Sculpture Garden, Austin

More recently, at Page, we participated in the design of Discovery Green in Houston, and, for the last few years, we have been working on Buffalo Bayou Park, also in Houston.  This newest project, which opened in October, includes many buildings spread throughout the park.

For a park building to do its job, it’s essential to feel connected to the landscape.  The intersection between structure and nature is critically important.  At Umlauf, there is that huge aforementioned porch and lots of glass in the primary pavilion.  At Buffalo Bayou Park, we did much the same with all of the buildings, including the restaurant, the bike rental and the kayak rental, each featuring a porch all the way around providing both full shade and dappled light.   The restaurant’s dining room has a large glass wall with a focus on a big, particular tree, as well as an adjacent lake, the bayou and the surrounding tree canopies.

A second big issue is scale.  One plausible approach might be to try to make a building disappear, but I think that’s problematic.  Park buildings need to be in scale with their big, open setting, and they often need to be visible at a distance to serve their purpose.  At Buffalo Bayou Park, the buildings’ scale is large and in keeping with the grandeur of the setting.

Above and below: The Lost Lake pavilion at Buffalo Bayou   Photo (c) G. Lyon Photography

The Lost Lake at Buffalo Bayou Park Photo (c) G. Lyon Photography

GLP_LOSTLAKE_120415-26 Gallery Size

Lost Lake Visitor Center/Event Space at Buffalo Bayou Park Photo (c) G. Lyon Photography

A third challenge is designing buildings to accommodate a lot of use and abuse.  Because of the flood plain at Buffalo Bayou we needed to plan many of the structures to be under water at times and vulnerable to floating debris.  We built them from stout board-formed concrete so that when there is a water event, the building withstands it.  After a significant water-level change, the concrete can be hosed off, and the structure is good to go again.  Last spring, we had huge rains in May after the buildings were pretty much complete, and there was no harm done.

Page - Waterworks Houston

View from The Water Works Visitor Center at Buffalo Bayou Park (c) Slyworks Photography

Places like Barton Springs Pool, Umlauf Sculpture Garden, Discovery Green and Buffalo Bayou Park are wonderful, egalitarian urban draws.  More than most places in our cities, they attract people of very diverse income levels and cultural backgrounds.  At the opening of Buffalo Bayou Park in October it was wonderful to watch a real cross section of the Houston population mingling together and enjoying a beautiful day in a beautiful spot.  Being able to be a part of making these kinds of places is as good as it gets as an architect.

Page - Waterworks Houston 13Mar2016-33

View to downtown Houston from The Water Works at Buffalo Bayou Park (c) Slyworks Photography

Page - Waterworks Houston 13Mar2016-27

The Water Works at Buffalo Bayou Park Houston (c) Slyworks Photography


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Thinking about Buildings in Landscape, Cultural Identity, Sustainability, Texas Architecture, Urbanism
Posted March 24, 2016

What does global architecture mean?

I recently traveled to Bolivia to participate in the XIII Seminario Internacional de Arquitectura, a biennial architectural conference held at the University of Santa Cruz de la Sierra.  I had spoken at the same conference fourteen years ago and, as was the case before, I really got my eyes opened about the current state of architecture in Bolivia and elsewhere in South America.  Three things particularly impressed me:

1).  We in America have a terrible misconception about many other parts of the world.  The picture portrayed in both general and architectural media seems really twisted. South America is mostly off the radar screen, although we do get a tiny glimpse occasionally. When it is portrayed, we see massive favelas or a few precious object buildings.

Both of the times I have spoken in this recurring conference in Bolivia, as well as the exposure I have had through the annual Latitudes conferences at University of Texas at Austin, have opened a window to a very sophisticated group of architects practicing in South America and to economies that are thriving and building at an impressive rate.  Talking with many of the architects in Bolivia it is clear they plowed though the 2008 economic downturn hardly missing a beat.  They are executing impressive school building programs, large neighborhoods of well-designed medium density housing and suburban planning that puts our ad hoc mish-mash in the US to shame.

Bolivia1 Bolivia2

2.  I was also impressed by the huge change that has happened in Santa Cruz since 2000.  The city has boomed, and has actually developed in a fairly orderly and intentional way.  There is a beautiful central historical core that is being nicely preserved and enhanced through careful controls and guidelines.

Still following a City Beautiful plan from the early 20th century, concentric rings of neighborhoods have been developed around the core. Traffic is served by a series of radial  and ring roads that have been consistently implemented over decades.  Santa Cruz is a garden city, and it reminds me of similarly well-planned cities in Australia.

The amount of construction is amazing, with design supplied by architects from Bolivia as well as other parts of South America. Both in the older part of the city, with its central square and the main cathedral, as well as on the periphery, there is evidence of really good urban design work that is actually being implemented.


3. The conference leaders assigned a number of architecture students from the Universidad Privada de Santa Cruz de la Sierra to take care of me, and the rest of the speakers who represented other countries in South America.  These students were incredible—bright, enthusiastic, curious and engaging.  They have tremendous pride in their region and their city and are extremely knowledgeable about both its history and its current development.


Their university has many travel and exchange programs all over the world, so these students had been around and knew global architecture as well as they knew the local scene.  The students and  faculty leaders loaded me up with recently published books about both local and larger regional architecture in Bolivia and elsewhere in South America.   Through both the educational system and  scholarship/publications, this culture is investing in a vigorous and promising future.

In the US we talk about globalization in architecture, but the content is pretty shallow and the perspective is sadly warped.  We hear a lot about Dubai and China—especially when big name architects from Europe and America plop their latest confection there.  But we know almost nothing about rapidly developing parts of the world like South America where there are many promising things happening in our field.







Thinking about Cultural Identity, Life as an Architect, Sustainability, Urbanism
Posted April 30, 2014

Constructing the UT Pan American Performing Arts Center

A couple of weeks ago, I visited the construction site for our new UT Pan American Performing Arts Center.  We’re using load-bearing masonry walls, and at this stage, with the project half-complete, the building has the look of a modern-day Roman ruin.  I love this stage of construction when the structure is coming out of the ground and turning into interesting forms and spaces.  The whole building process is incredibly exciting and inspiring.


This will be a big building and a real landmark.  It will serve as the campus gateway and will feature a 1,000-seat performance hall as its centerpiece.  It is part of a complex for the arts on a campus originally designed by Kenneth Benston in the 1980s.  His work was inspired by Louis Kahn’s buildings in Dacca, Bangladesh and Ahmedabad, India.  Those Kahn buildings were masterpieces of masonry construction, and Bentson did a good job of learning from them.


South Texas is a very hot, semi-tropical climate where the terrain is absolutely flat—not so different from Dacca and Ahmedabad.  Masonry has long been a prominent building material in the region.  As a kid, my grandparents lived in this area, and I have keen memories of the powerful brick buildings in a landscape full of citrus and palm trees.


From the start, we wondered if we could make a real masonry building here—not brick veneer on a steel or concrete frame, but thick, strong load bearing walls.  In fact, real masonry walls turned out to be a very practical and economical structural system for this building in this region.

In the end, the walls will be a hybrid system—much like Kahn used and much like the Roman’s used in the precedents Kahn so admired.  We will use both brick and concrete block, and the block will often be employed to create formwork for concrete lintels, piers and arches.  This general construction technique is quite common in Mexico, just across the border, but is not so common elsewhere in the United States.   It is  fascinating to watch it go up.


There are large, circular and arched forms in the walls.  These impart a great sense of strength and power that isn’t so palpable in the kind of frame construction we normally do.  There is a definite toughness about it, and it reminds me of the experience of seeing Kahn’s work in South Asia years ago.  There will be extensive glazed walls once the building is complete later this year that will provide a nice counterpart to the masonry in the finished building.


In addition to the main performance hall (which is clearly visible in its roofless form in the construction photos), there will be four rehearsal halls for choir, band, orchestra and mariachi.  They form a village of rectangular rooms behind the concert space.  When completed, the building will serve, not only as an important educational facility for the university, but also a cultural and performance center for the larger Rio Grande Valley.



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Thinking about Building Technology, Buildings in Landscape, Campus Architecture, Contemporary Practices, Cultural Identity, Sustainability, Texas Architecture
Posted March 24, 2014

A perfect building? Quite possibly, yes.

This summer I visited Vancouver, certainly one of the most spectacular urban settings in the world.  While there, I met with Mark Reddington, partner of LMN Architects of Seattle, and Ken Cretney, chief operating officer for the Vancouver Convention Centre.  Ken came on board with the center six months before the building was finished; as such, he wasn’t the original client for the project and is now responsible for the building’s ongoing function and performance.  LMN are the architects for the Convention Centre West, the only building to win a National AIA Award for Interiors, for Architecture, and for Urban Design.  The building has also been recognized by The Committee on the Environment (COTE); by World Architecture News (both as the Most Sustainable Building in the World as well as recipient of its Effectiveness Award, and by the Urban Land Institute (ULI).

Convention Centre on Vancouver's waterfront

Convention Centre on Vancouver’s waterfront

The building interfaces beautifully with the street

The building interfaces beautifully with the street

This is a truly amazing building.  It interfaces beautifully with the street, the city, the water, and with a park that outlines Vancouver Island.  At street level, there is retail that gives a pedestrian friendly face to a building type that can be daunting. All of the typically unsightly elements associated with large convention centers (e.g., buses, trucks, parking, loading docks) are underground; thus, there reduced congestion around the building.  As I learned from Mark and Ken during our tour, there were all sorts of issues from a sustainability perspective, including marine ecology.  The solution to that problem was to create a new enriched environment for the marine life in Vancouver Harbor.  In terms of form and character, it’s substantially built with local materials, employs extensive local artwork and it absolutely celebrates daylight.  I find it extraordinary that it does all these things extremely well and never feels like one design consideration trumps or overwhelms the others. In fact, they all reinforce one another.

Ample daylight throughout the interior

Ample daylight throughout the interior

Substantial use of local materials

Substantial use of local materials

The net result is a building that makes a real difference, both to the city and to its citizens.  It is also a highly effective marketing tool.  As Ken noted, “the architecture really enhances any event held here.  Conventions are more exciting and dynamic… because of the building.”  He pointed out the main ballroom, which has a moving wall to reveal beautiful views of the harbor and the mountains beyond.  The interior is a warm, ingratiating space full of light that encourages people to stay.  In short, the building contributes to its primary purpose: having great events.  Ken added that if convention committee people see the building, almost invariably they book it.

The architecture enhances any event held here

The architecture enhances any event held here

This project is a huge economic engine and generates a lot of money for the city’s hotels, restaurants, and tax revenues.  The success of the design brings in millions of dollars to Vancouver, which now competes with the global cities for significant events.  Equally important, the building makes a visible contribution to the city’s residents who go by and engage with it every day.  It’s a source of pride and excitement; people go there just to hang out.

Twilight and crowds gather in front of the building

Twilight and crowds gather in front of the building

I genuinely love buildings like this one.  They make the life of a city and the lives of its residents better!  This is the true potential of architecture – to transform the energy, vitality and economy of a place.  The power of the building goes way beyond what you can see in a photograph and attests to just how meager an experience of image alone is to the real understanding of great architecture.

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Thinking about Building Technology, Buildings in Landscape, Cultural Identity, Sustainability, Urbanism
Posted November 7, 2013

Micro-housing’s time has come … again.

Several years ago, I visited the Weissenhof Estate, an experimental residential complex built on a hillside outside Stuttgart in 1927.  Some of the most recognizable names in 20th century architecture were contributors to the buildings and the project’s success, including Le Corbusier, Mies van der Rohe, and Peter Behrens, among others.  Their goal was to provide affordable housing, something urgently needed in Germany between the wars. The units were designed to accommodate a mixture of income groups, from blue-collar workers to upper middle class.   Weissenhof has become a landmark in the development of modern architecture, but the original intent was really to address a pressing social problem.  It was an extraordinary effort – very simple and very economical.

The Weissenhof Estate, Stuttgart, Germany 1927The Weissenhof Estate, Stuttgart, Germany 1927The Weissenhof

I am speaking at a conference this month that addresses these same affordable housing issues we’re facing in America now.  I will be talking about the promising notion of micro-housing, an approach that I think has real viability.  In 1950’s America, the average house size house was 1,200 square feet; it’s more than double that today, and yet families are smaller.  We create a lot of built space today that is just not needed.   This kind of consumption wastes construction resources and is expensive.  Looking back at what the Germans accomplished in the late 1920’s, we can learn lessons from architects that were working like crazy to provide just what was really needed – lean, elegant design that was still quite amenable and comfortable.  I think we should be trying to do that again now.

Recently, Architectural Record covered a micro-housing competition in Denver. There were four winners, all published. I was dismayed by the results.  Each winning entry seemed extravagant.  The whole idea of micro-housing is to stay simple, purposeful.  The winners all proposed extensive perimeter, which means high initial construction costs and long-term higher energy bills.  Building forms were intricate and clearly complicated to build and difficult to maintain.  They were, of course, cool-looking with scaffolds and lots of meandering exterior stairs and even detachable pods that could be floated on the adjacent river.

Proposed micro-housing project, DenverProposed micro-housing project, DenverProposed micro-housing, DenverProposed micro-housing, Denver

Are we as architects really trying to solve serious problems, or are we just interested in self-indulgent play?  How can we create the most live-ability in a housing project while also being energy efficient and economical in terms of other resource consumption?  These are equally critical forces in affordability.  Could a very striking, innovative visual character emerge from a genuine investigation of real problems as it did in Stuttgart?

I’d like to laud the premise the Germans set out almost a century ago.  The units at Weissenhof are small but very nurturing places to live – even a hundred years later!  Couldn’t we make some equally great micro-units now that grow out of current needs and technologies?

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Thinking about Building Technology, Contemporary Practices, Sustainability, Urbanism
Posted July 25, 2013

What role for architects in planning future cities?

A recent article by Aaron Betsky in Architect magazine took issue with a New York Times-sponsored program called the Energy For Tomorrow Conference.  Betsky was specifically concerned that the Times had not included any “urbanists, planners, or even an architect” but did include “leading urban expert Jeremy Irons.” He queried, “What are architects when we’re thinking about the future of the designed environment… chopped liver?”  Betsky suggested several prominent architects would have been an appropriate addition, including OMA and Diller Scofidio + Renfro, among others.  While I agree we should expect some architects and urbanists at such a conference, I question some of Betsky’s suggestions.  Are the starchitects he mentioned really contributing to energy efficient, sustainable cities?

Early in his career, Rem Koolhaas of OMA advocated for density and intense urban vitality, but then seems to have decided object buildings were the thing.  He has done projects that seem remarkably anti-urban and marked his career with buildings that don’t make great cities.  The gargantuan CCTV tower in Beijing is a prime example.  That building required demolishing an entire neighborhood in order to install a prominent object.  The streetscape and pedestrian quality suffer in order to create a geometric, one-liner statement that has a crushing scale at ground level. Do snazzy object building with poor pedestrian environments around them really make a sustainable city?

The CCTV complex in Beijing

Above: The CCTV complex in Beijing

I have written before about the problems of the accumulated object buildings by starchitects in the Dallas Arts District that fail to create a good urban environment.  OMA was involved there as well with the Wyly Theatre where both the main entry and lobby (the most lively parts that might enrich an urban neighborhood) are submerged a level below the street, but easily accessed via underground parking.  Creating an auto-centric building in a downtown environment – one that is desperately trying to make real headway toward mass transit and pedestrian-friendly movement – hardly seems the sort of decision one would want to hear about in a conference dedicated to energy savings and sustainable cities.

Above and below: The Wyly Theatre in Dallas


Christopher Hawthorne of the Los Angeles Times recently slammed the new Perot Museum of Nature and Science in the same Dallas district, calling it “bullhorn urbanism.”  That’s what we, as architects, have become known for: big, loud, sexy object that are more about themselves than about making a city.

The Perrot Museum in Dallas

Above: The Perrot Museum in Dallas

Look at Dubai and dozens of huge cities across China which have received huge press in architectural circles. They are what we have touted as great successes, but they are not sustainable urban environments.  If that’s the best we can do, then we don’t deserve to be at the tables of forward-thinking conferences.


Above: The Dubai skyline

To Betsky’s credit, he observes a little later in his piece, “Perhaps they are right.  The one bit of designed infrastructure going in up in New York right now, the Calatrava station at ground zero, is a farce…” I wonder if this is the reason they’ve left architects out of the discussion.  We have got to start talking about real issues that are important to a larger society and not just about glitzy structures.  We need architects and planners to speak up on this topic – and loudly.  We need our media to be focused on real, relevant issues the larger culture cares about.  Then we will be invited to the table when those important matters are being discussed about the future of our cities.

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Thinking about Building Technology, Contemporary Practices, Sustainability, Texas Architecture, Urbanism
Posted June 11, 2013

Austin City Hall

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Thinking about Sustainability, Texas Architecture
Posted January 16, 2013

High Performing Thermal Mass in New Mexico

Increasingly, I’m more interested in what architecture does than just what it is.  In a previous blog, I wrote about the new office building we designed for Wiss, Janney, Elstner Associates (WJE), in Austin, and the use of thermal mass to control temperature.  We’ve now employed those same sustainable principles for a residence in northern New Mexico.  The rammed-earth structure, located outside Santa Fe, virtually disappears into its site and surroundings.  For the earthen walls, we selected four shades of the indigenous sedimentary dirt to create a deep, luscious palette, and it’s used for both exterior and interior surfaces.  In fact, these are much the same colors and hues Georgia O’Keefe found in the same landscape and can often be seen in her paintings.  I’m thrilled with how it all turned out, as are the homeowners.  The house is invisible from the street and even when approached close up, one must proceed through vegetation and down a broad stair into a courtyard.  Only then can one see the entire house.

How all these elements – location, materials, building placement, wall density – work together is the real story here.  At 6,200 feet, the local climate is high, arid desert with very warm summertime temperatures and a sharply colder winter.  By siting the building to face south, we gained excellent winter solar exposure.  Large, ipe wood overhangs and a trellis act as a brise soleil, while the dense walls soak up the daily solar gain and radiate it back at night.  The huge, sliding, high-performance glass door openings permit a comfortable, steady cross-ventilation fed by the mountain chaparrals. With the deep sunshades, the house is pretty much clear of the sun’s arc in the summer sky, and yet takes full advantage of the direct light in the cooler months.  The result is that both air conditioning and heating requirements are greatly reduced, although systems for each are carefully integrated into the structure and are there as a back up.  Sophisticated sensors in the house monitor temperature swings (which, so far, are virtually non-existent).  In short, we’ve built a beautiful, self-regulating performance envelope with essentially just dirt.

Inside, the concrete floors (with embedded radiant heat) were made using local gravel cast into the final mix, and then diamond-finished as one would with terrazzo.  As with the walls, the floors have a solid, rich visual quality and their colors are seen not only inside the house but also out in the broader landscape.

In designing the thermal performance of the house we used largely empirical methods.  We looked at what had been done elsewhere, how it had been done, and what worked.  This method has been used for centuries, long before computers and high-tech calculations.  One can see countless similar examples among ancient architecture in Turkey, India, Egypt, and China.  We did, of course, consult an engineer for the radiant heat.

Given the excellent monitoring devices built into the house, we will be able to tell how well this house works over various seasons.  I am really interested in and committed to the ultimate outcome that we need to measure for a substantial period of time.  Might be good for a follow-up blog in the future.  I’ll keep you posted.

Thinking about Building Technology, Buildings in Landscape, Contemporary Practices, Sustainability
Posted October 28, 2012

Building With High Thermal Mass in Hot, Humid Climates

It is hot and humid as hell in most of Texas at the moment.  The current conditions call into question whether our normal way of dealing with summer heat (using primarily insulation and air conditioning for cooling) is the only economical and ecological approach to these climate extremes.

I became interested using high thermal mass as an alternative while traveling in Turkey with my son Sloan eight years ago. He and I visited remote Roman ruins on the south coast and the interior, where the sites are in raw states and are not much frequented by tourists.  The summer climate in Turkey is very hot and humid, not unlike Texas. But it was strikingly comfortable inside the stone ruins with their high thermal mass.

I noted the same effect working beautifully in the all-masonry city of Ping Yao in western China, where homes have thick, stone walls and massive, stone beds that kept us amazingly cool on hot summer nights.

This is a classic heating and cooling technique in climates with high diurnal swing where the thermal mass dampens large fluctuations between hot days and cool nights.  We have used rammed-earth walls effectively in places like Santa Fe to achieve this advantage.

But when we used thick concrete walls for blast protection in a government office building in Houston, we also found that high mass could work to our thermal advantage.  That building was pleasantly cool under construction before the air conditioning was turned on, and it made me wonder—why aren’t we doing more of this in Texas? Why is high insulation and air conditioning the only method of cooling?

Wiss, Janney, Elstner Associates, a renowned firm of building and forensic engineers, recently approached PageSoutherlandPage to design its one-story Austin office building, giving us a unique opportunity to thoroughly explore and analyze this question. WJE’s Austin office includes a bunch of the country’s best concrete experts.  When we proposed using high thermal mass concrete walls for their building, they saw an interesting test case. They used a WUFI model to demonstrate how temperature would move through the thick concrete walls at all hours of the day and all times of year.  They analyzed when the walls could produce thermal advantage as well as when dew point would be reached that might create condensation. In the end, the engineers convinced themselves and us it was worthwhile to proceed.

This had to be a pretty inexpensive building—a small office for a small business. Our budget was equivalent to a stud wall building with brick or stone veneer. The structural loads on the walls were modest and, of course, greater thickness worked to our thermal advantage.  So we built unreinforced concrete walls—pure compression structures.  The absence of rebar along with the fact that all of the formwork was kept to simple rectangles meant labor costs became low enough to be affordable.  When we were pouring the walls, everyone said the finished pieces looked like Stonehenge.

This project is very experimental, but we have the engineers’ analysis to tell us how the material will behave. Architecturally, the concrete has a beautiful look and feel, which we didn’t fuss up at all.  Though the air conditioning has not been activated and the temperature is approaching 100 degrees outside, the building interior is surprisingly cool.

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Thinking about Building Technology, Contemporary Practices, Sustainability
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Posted August 6, 2012