Green Walls, Roofs, and Buildings for the Greater Good

Have you noticed the many lush vine-covered walls around Santa Barbara like the one on the Ortega Street parking garage along Anacapa?  Yes, they are beautiful, but many people’s first response is “but rats!”  The latest technology in living walls, also known as bio-walls or green walls, is quite different than what is currently seen around town.  The plants on these newer walls are not vines.  They do not harm the architectural finish of a building the way vines can, nor are they jungle gyms for rodents. 

With the green building movement finally gaining ground, numerous companies offer proprietary systems that are typically square modules with a soil-like substrate and internal drainage system that can support various types of plants, even edible options.  Denser than vines, the plants often completely hide the wall behind it.  If designed correctly, they are low maintenance, and require minimal water.

Green roofs are seeing an even bigger resurgence than walls. Both living roofs and walls can enormously benefit our cities’ air quality and overheated microclimates, save energy with their insulating properties, help manage water run-off, and provide park-like settings for the enjoyment of building occupants. 

Green roofs are not new.  They’ve been around for thousands of years.  But in modern times, flat roofs have been covered in tar, asphalt, and equipment which needed a lot of maintenance, but architects didn’t worry much about them since nobody could see them.  Now, many of these roofs are being converted into gardens, a relatively inexpensive and easy undertaking.

These roofs, sometimes in the form of half buried buildings with public parks on top, are helping buildings get approved by cities that would otherwise be impossible to get through the political process. They have turned into planning tools to help put buildings where no building has gone before, are radically changing the architectural form of buildings, and the respective roles of architects and landscape architects.  Architects are using green roofs to make buildings become part of the landscape with the line between architecture and landscape architecture disappearing.

What’s an architect to do when they come to realize that the product of their livelihood is destroying both our planet and our health?  Most architects went into the profession to change the world for the better.  When designed well, buildings enhance and improve lives.  Yet buildings account for about half of all carbon emissions and energy consumption, more than any other single contributor to our environmental woes.  Moreover, one quarter of what is in our landfills is construction waste. 

The challenge has been that most American developers don’t want to pay the additional upfront cost that green buildings require.  Fortunately, this upfront cost is decreasing with better technology and design.  Moreover, the initial cost of constructing a building is only about 10% of the overall cost of maintaining the building over its life.  We can no longer afford not to build green buildings.  Europeans have known this for some time, and have led the way.

Many architects have accepted the challenge to design only “net-zero” buildings – building that have no negative environmental impact – by the year 2030, and governments have finally started to mandate some form of green design for new buildings.  But existing buildings, not new buildings, are responsible for the vast majority of energy consumption.  Therefore, renovations are crucial to the cause.  Since 1992, federal law has required all existing commercial and multi-family residential buildings to be upgraded to comply with the Americans with Disabilities Act, enabling access to buildings by the disabled.  Why isn’t there a federal law mandating that all existing buildings are upgraded for energy efficiency, enabling a healthy lifestyle for all?

Green remodels have become trendy, but it is not green to rip out materials, most of which will end up in a landfill, only to install new “green” materials that used some, although perhaps minimal, energy to produce.  It is greener to live with existing materials as long as possible with a few exceptions.  If materials are off-gassing hazardous chemicals, as many carpets, paints, cabinets, and fabrics do, they should be removed.  Replacing insulation, appliances, HVAC systems, lighting, windows, faucets, and toilets for new efficient models is absolutely worth doing.  Numerous government and utility rebates can assist with the upfront cost of doing so. 

Although hugely important, green buildings alone cannot solve our environmental and health problems.  Adopting alternative modes of transportation such as rail systems, walking, and biking is also critical in redesigning not only our buildings, but our cities for increased livability with less dependence on cars.

Our culture’s short-sightedness and disposable mindset helped create an economic landfill – the worst recession in eighty years.  Now that we’ve seen the error in our way of thinking, our country has finally started to embrace the idea of sustainable design.

Simple Is Better: No-Cost Sustainable Design

Buildings account for 40% of the nation’s energy consumption.  Homes account for about half of this total.  When I was in architectural school 20 years ago, strict and unforgiving professors, aware of this issue, drilled passive design concepts into our idealist minds.  Architects, as a rule, are environmentalists, but those who hire us, the developers, are not.  Until now that is.  It is only recently that clients are finally ready to embrace sustainable, or “green,” design, something many architects have been passionate about since the late 1960’s. 

The biggest roadblock to designing greener buildings has been cost which, until recently, did not achieve an appropriate payback time period.  Providing air-tight, well-insulated buildings with energy-efficient appliances offers the biggest bang for the buck, however there’s an upfront cost in utilizing the latest technologies to achieve these goals.  But sometimes, an old-fashioned and simple design is better than the latest technology. “Passive design” techniques that have been around for ages can be easily implemented for new construction projects with no added cost whatsoever.  Below are a few basic approaches that will save a great deal in air conditioning, heating, and lighting expenses over the building’s life as well as at the time of construction. 

Consider the orientation of the building to the sun.  If the size and shape of the property allow, the longer sides of a building should face north and south with the shorter sides facing east and west.   The north side receives no direct sunlight as the south side basks in the sun’s golden rays.    To the east and west, the sun is at a low elevation as it rises and sets, so its rays hit the house almost horizontally, translating to more heat gain.  The hottest and most detrimental rays are in the late afternoon as the sun sets in the west.  

Windows are a double-edged sword when it comes to designing sustainably.  They are crucial for adequate day lighting, fresh air, and a view to the outdoors.  But even the most energy-efficient windows are like gaping holes in a building envelope when it comes to heat gain and loss.  Glass, not to mention the air gaps in window assemblies, transfers heat or cold significantly more than typical wood-framed walls do.  Therefore, window placement is critical in passive design.

Windows facing north offer great day lighting with no solar gain, but can result in a ton of heat loss when submitted to northern winter winds in cold climates.  Heat gain and loss is easiest to manage on the south side where well-designed shading devices allow the sun’s rays to hit the windows in the winter when the sun is lower in the sky, but protect the windows from direct sunlight in the summer when the sun is higher.  Southern windows offer the best of both worlds when designed appropriately, but can backfire big-time when not.

Western-facing windows should be avoided altogether, if feasible, where it is best to place rooms that do not require them such as closets or the garage.  East-facing windows should be minimal since the morning sun, although not as hot as in the afternoon, also enters almost horizontally.

Providing low windows on the walls that predominantly receive cool summer breezes, and high windows on the leeward walls permits a way for cool air to enter a building and hot air to escape.  Of course, other considerations, like views, are also significant determining factors in window placement and must be balanced with passive design needs.

Heat that is absorbed into the building during the day can quickly escape from the windows during the cold night when it is needed most.  To maintain a comfortable temperature at night, a thermal mass can be utilized.  This is typically a thick masonry or concrete wall or floor that receives solar gain directly or through glass.  Masonry or concrete slowly release the heat it stored during the warm day.  This is just one of the several benefits ofexposed concrete floors.

Passive design not only helps the environment, it also supports the health and wellbeing of a building’s occupants.  Heating and air-conditioning are not as comfortable or healthy as natural ventilation.  Many have been overly focused on green finishes like bamboo flooring and recycled glass tile, because those are the things we can see and feel.  Finishes are fun, don’t get me wrong.   But the biggest impact on our wallets and on the environment is in reducing consumed energy over the life of a building.