What Are The Current Best Building Practices?

Many people relocate to lowcountry from inland communities where there are not hurricanes. So often the first question a new resident asks is "What are the best practices for building in a hurricane prone area?". Buildings need to simultaneously resist wind, rain, and flood. The International Residential Building Code (IRC) made significant revisions after Hurricane Andrew that have been proven to prevent structural damage from wind. In fact, during the 2004 Florida hurricanes, no one died in any structure that was built under the revised code. The code requires that the building is tied together from the roof rafters to the foundation; the building is designed to withstand wind shear; the windows, doors, and skylights are protected from windborne debris; and the exterior finishes are securely fastened to the structure.

Keeping The Rain Out

The success of the structural code changes highlighted the problem of rain entry into the building. Before when a homeowner was missing a roof, he was not concerned with a leaky window. Preventing rain infiltration is now a new focus in home construction. Many property insurance companies will give homeowners a discount for some of these best practices. The key items include: The roof needs an overhang to keep the rain off the building; provide sill pans under all windows and doors; flash all windows, doors and other penetrations; provide a drainage plane behind the exterior finish material to allow the water to escape and the wall to dry; provide a secondary roofing membrane; design closed crawl spaces that are dry and watertight; and drain the rain away from the house through the use of gutters and sloping the ground away from the building.

Keeping Flood Waters Out

The U.S. Federal Emergency Management Agency (FEMA) has understood for several decades how to prevent flood damage. The basics are general common sense; elevate the livable space, floor structure and heating and air-conditioning ducts above the 100 year flood plane and the potential storm surge; install hydro-static vents to prevent flood waters from collapsing foundation walls; build with materials that tolerate getting wet; and design the walls to easily dry after they get wet.

The ASHRAE Guide for Buildings in Hot, Humid Climates recommends to design and construct buildings in hurricane prone areas using the following steps in order of priority: keep the building from blowing away; keep the rain out; elevate the structure above the flood plane; building with materials that tolerate soaking; and design the wall assemblies to easily dry with they become wet.


How Can My Home Be More Sustainable?

How can my home be more sustainable? Southern vernacular building techniques are based on sustainable principles which we continue to use today.

Southern Vernacular Lessons

Prior to the advent of air conditioning, an understanding of local environments enabled southerners to build in ways that buffered the harsh climatic realities. As Europeans moved to the southern colonies it typically took them a generation to adapt their native architecture to the climatic conditions of the region. Five lessons they learned are equally important today.

  1. Houses one room thick maximized cross ventilation. The thin plans also provided ample light that prohibited mold growth in dark areas.
  2. The best orientation of this thin plan was east to west to reduce solar gain. The windows were located to catch the prevailing summer breezes.
  3. Large porches or verandas were always located on the southern side and often on the east and west, too. The verandas protected the house from both the sun and the rain, provided circulation, and created a cool place to sit and sleep in the summertime.
  4. High ceilings allowed the heat to rise and provided a more comfortable environment.
  5. By raising the houses off the ground several things were accomplished; it allowed the first floor to be out of the flood plain in coastal areas; breezes are better on the raised first floor; and air circulating under the house helped reduce the heat gain.

Next Steps

Additional components for a sustainable house include the following:

  1. Use sunscreens and large overhangs to block the summer sun
  2. Detail and build a airtight house
  3. Keep all HVAC ducts and equipment in conditioned or semi-conditioned space
  4. Use high efficiency heating and cooling equipment
  5. Use durable, safe, local materials with post consumer recycled content
  6. Use excellent insulation
  7. Use LED lighting

 

Certificate Programs

There are several certification programs active in the Lowcountry. They all have third party verification requirements and different programs for different building types. Some require performance -based measurements while others have a prescriptive path to the desired performance level. The non-residential programs are led by the design team of architects and engineers and the residential programs are under the purview of the contractor.

There are five general areas that all the programs measure; Sustainable Sites, Water Efficiency, Energy Use, Materials and Resources, and Indoor Environmental Quality. There are mandatory requirements and a minimum number of earned points in each category. Each program awards different levels of certification based on the number of points earned. For example the LEED programs are LEED Certified, LEED Silver, LEED Gold, and the highest rated LEED Platinum. The areas overlap and green strategies can often result in points in several categories. The decision to have daylight in all interior spaces can gain points in Energy Use (less need for electric lights) and Indoor Environmental Quality (occupants’ well being is better with daylight and a view).

 Sustainable Sites

Sustainable site requirements are focused on minimizing the building impact which includes: locating the project in a developed area, preferably on a pre-developed site within walking distance of essential services; using regionally appropriate landscaping; controlling stormwater runoff both during and after construction; and reducing erosion, light pollution, and construction related pollution. Beaufort County averages almost 50 inches of rainfall a year. This creates an opportunity to retain the water in a cistern for use in landscape irrigation or for non-potable domestic water use.

Water Efficiency

Water Efficiency rewards water conservation both inside and outside. The interior strategies include high efficient appliances, fixtures and fittings. Water-wise landscaping and water harvesting in rain barrels or cisterns for reuse are exterior conservation options.

Energy Efficiency

The single most important category is Energy & Atmosphere, where the overall goal is to reduce energy consumption and encourage the generation of renewal energy. Strategies include: energy use monitoring; efficient design and construction; efficient appliances, HVAC systems and lighting; use of renewable and clean sources of energy generated on-site or off-site; and natural daylight in spaces by windows or skylights. Many homeowners want to go to the next level by creating their own energy with solar panels or wind generators and heating their own hot water with solar hot water heaters. A solar electric system qualifies for both federal and state tax credits and net metering from the power company.

Material

Materials & Resources promote the selection of sustainably grown, harvested, produced and transported products and materials. This category also is concerned with the reduction of waste both from the construction site and the manufacturer’s site as well as reuse and recycling. Attention is given to the travel distance of materials and resources to the construction site and to the manufacturer’s plant. Reuse of an existing building, recycled materials, and locally produced materials are the high point favorites.

Indoor Air Quality

Indoor Environmental Quality strives to improve indoor air quality; access to natural daylight and views; and improving acoustics. The category focuses on reducing indoor pollutants such as VOC’s (Volatile Organic Compounds) in paint and off gassing of irritants found in adhesives, carpets, composite wood products and furniture. Strategies include managing moisture to prevent mold, increasing ventilation rates and mechanical controls to maintain the proper levels of temperature and humidity.

According to the United States Green Building Council, buildings account for approximately 39% of total annual US energy consumption (31% for building operations, 8% for building construction). Building operations (heating, cooling, ventilation, hot water, etc.) account for 38% of total annual US greenhouse gas emissions. And 72% of all the electricity produced at power plants in the US goes to operate buildings. So it is time for us all to learn more about green building and consider getting your project certified. You might even qualify for a tax credit.


double front porch

The Southern Vernacular Traditions

Southern Vernacular Traditions

Prior to the advent of air conditioning, an understanding of local environments enabled southerners to build in ways that buffered the harsh climatic realities. As we design for a more sustainable and resilient future we can learn from the past. Looking back we can see that southern vernacular designs are inherently sustainable and resilient because they reflect their locale in terms of building materials and the response to the climatic conditions of the region before air conditioning allowed us to ignore that it was hot and humid outside.  Southern vernacular houses have commonalities in the siting, form, and materials.

Siting 

The best orientation is for the long axis to run east to west to reduce solar gain. The windows are located to catch the prevailing summer breezes. Large porches or verandas were are usually located on the southern side and often on the east and west, too. The verandas protected the house from both the sun and the rain, provided circulation, and created a cool place to sit and sleep in the summertime. By raising the house off the ground several things were accomplished; it allowed the first floor to be out of the flood plain in coastal areas; breezes are better on the raised first floor; and air circulating under the house helped reduce the heat gain.

Climate informed the Form

Houses one room thick maximized cross ventilation. The thin plans also provided ample light that prohibited mold growth in dark areas. High ceilings allowed the heat to rise and provided a more comfortable environment. Kitchens were usually in a separate building behind the house; this kept the heat from the fireplace out of the main house and also protected the main house in the event of a kitchen fire. Privies were located even further away with a tea olive or other sweet smelling bush planted nearby.

Materials

were local and durable. Exterior siding and wood shake roofs were made from rot resistant Cypress in the coastal south. Framing and flooring were made from Long Leaf Pine. Bricks were made of local clay and their colors identify the locale. Tabby is a traditional material made of oyster shells and lime.

There are several archetypes that have evolved over the years. One that is extremely common and can be found from Tennessee to Florida is the dogtrot. The dogtrot is also known as "two pens and a passage". One room was typically used for sleeping and the other for cooking. The covered open center passage was the main sitting room in warm weather that was cooled naturally by breezes that intensified in the open passage. The center passage was often used as the dog kennel and thus the name dog trot.

The original dog trots were made of logs with a fireplace on each end. Later dog trots were framed with wood siding.  In his book, The Cotton Kingdom, Frederick Law Olmsted described a dog trot he visited in Louisiana in 1850, "The house was a double log cabin—two log erections, that is, joined by one long roof, leaving an open space between. A gallery, extending across the whole front, serves for a pleasant sitting-room in summer.“

southern vernacular

This photograph is  Jane Frederick’s great-grandmother Essie Curl and her sister Ezzie Pearl Shackelford with their parents in front of their dogtrot home in Fayette, Alabama. Inspired by the inherent sustainability of the dogtrot, Frederick + Frederick Architects explores the traditional forms in contemporary designs.

dogtrot swimming pool

The dogtrot space in this contemporary house is used as a sitting room overlooking the swimming pool and river. The house draws on the vernacular vocabulary of siting east to west with a single room width to maximize cross breezes. The dogtrot separates the master suite from the great room. It can be closed with custom made wooden gates.

bluffton sc dogtrot

This modern interpretation allows the dogtrot space to be opened up during good weather and closed with folding glass doors to be conditioned when it is too cold or hot. There are retractable screens to keep the bugs out.