17. Floodproofing
Ordinarily a building such as this, located in a flood plain and undergoing such extensive renovation, would have to be elevated at a level above Base Flood Elevation (BFE) in order to qualify for flood insurance coverage under the National Flood Insurance Program (NFIP).  BFE is an estimate of the water level from a flood with a one percent chance of occurring in any given year. 

However, because this house is located in an historic district, the rules are slightly different.  In an historic district, if elevating a structure would harm its historic character, the elevation requirement may be waived.  This is exactly what happened in this case.  Because the building couldn’t be elevated to BFE, other measures, known as “wet flood proofing”, were taken. 

As mentioned below (see Foundation and Insulation) the house was partially elevated to keep it above the threat of small flood events without harming its historic character.  It was also insulated with non-water absorbing foam insulation under the first floor.  Several additional floodproofing elements can be seen on the first floor of the building.

 All electric, telephone and computer outlets have been located above BFE.  In addition, there are no splices or connections below BFE.  So if a major flood event does occur damage to the electrical system of the house will be absent or minimal. 

Wainscoting
 On the first floor notice that wooden panels, called wainscoting, have been installed to approximately BFE.  These panels are less water-absorbent than is wallboard and can be removed after a flood event, allowing both the panels and the wall space to dry thoroughly.  Wallboard absorbs water, which then wicks upward damaging walls to a level well above the actual flood level. 

Insulation
 There are three kinds of insulation used in the house.  Modern homes have well insulated exterior walls, roofs and floors.  The first floor is insulated with solid foam panels that fit in between the floor joists.  This material was selected in place of the more usual fiberglass batts as a part of the wet-floodproofing design.  If there were a flood and the foam insulation were torn from under the floor, it could be recovered and re-installed because it doesn’t absorb water.  As under the floor, the wall insulation on the first floor below BFE consists of solid foam, non-water-absorbing panels.  Above the foam, blocking has been installed to create a physical barrier to prevent water from damaging the insulation above.

In the walls above base flood level in the first floor walls, in the second and third floor walls, a relatively new insulation material has been used – cellulose.  Cellulose insulation is essentially ground up newspaper, treated with boric acid for fire retardation and insect resistance.  An adhesive is also added so that it can literally be blown into vertical wall spaces without appreciable settling.  This insulation can be seen in a demonstration panel on the first floor and in a much larger area on the third floor.  Research done at the University of Colorado has shown that cellulose outperforms fiberglass, reducing energy consumption by 26% to 38%.  Cellulose also has much better air-penetration resistance than fiberglass because of its higher density.  This contributes to its nearly 50% greater efficiency than fiberglass at very low temperatures.  Its use contributes to reduction of waste from old newspapers and other paper going into landfills.  Production and energy costs are also substantially lower than for fiberglass insulation.

Traditional fiberglass batts have been used between the roof rafters and can be seen at the exposed edge of the sheet rocked ceiling along the east wall on the third floor. 

HVAC System
 Note also that the HVAC unit and returns are located above BFE.  Also, the duct work has been installed at ceiling height to prevent flood damage. See 22., Geothermal Heating and Cooling System, for more information about the HVAC system.

18. Fireplace
The original fireplace and chimney were badly deteriorated and collapsed in the process of elevating the house.  Like most fireplaces and chimneys, the originals were non-reinforced, meaning they were constructed of brick and mortar alone, with no steel reinforcing bars.  This lack of reinforcement makes them very dangerous in earthquakes and hurricanes.  The force of shaking in an earthquake or the force of the wind can cause non-reinforced masonry to collapse.  It is very difficult to make a masonry fireplace and chimney safe from these hazards. 

There are however things that can be done to make fireplaces and chimneys safer.  Here you can see a special cement flue liner that can be built-in to new chimneys or retrofit into existing ones to provide additional strength to the structure and help hold it together when shaken by earthquakes or blown by hurricane winds.  The liner fills cracks in the chimney and replaces old mortar. 

Another option for an existing chimney could be to “frame-in” an interior masonry chimney.  By creating a box around the chimney, if it were to collapse, it would collapse within the framing.  It is also possible to fill the entire chimney with a cement grout, making it non-functional, but safer.  Any of these efforts represents a compromise, since it is safest not to have an non-reinforced brick fireplace and chimney in a seismic zone, like Charleston. 

 19. Foundation
The original foundation at 113 Calhoun was "brick on dirt"—non-reinforced brick laid on a compressed earth footing buried about three feet in the ground.  Due to the extreme deterioration of the original foundation, it was completely replaced in the course of renovation.  Detailed drawings of the foundation before and after renovation are available.

The new foundation consists of a concrete footing reinforced with steel rods.  On the footing concrete block replaced the original brick.  The block was filled with a concrete grout into which threaded steel rods were anchored.  These rods allowed the new timber “sills” to be bolted onto the foundation.  This retrofit provides the building with greater resistance to shaking and twisting from earthquake and wind forces, as well as preventing it from floating off its foundation in a severe flood. 

The original brick from the foundation was re-used as a veneer over the concrete block to preserve the original look of the building in keeping with its historic character, and conserving resources through their re-use. 

In the course of re-building the foundation, the building was elevated by about one foot.  This small elevation produced a great benefit in flood protection.  The house is located in a flood plain.  It’s first floor elevation is almost four feet below “Base Flood Elevation”, a measure of flood vulnerability.  Clemson University Civil Engineers calculated that by raising the building just a foot, it would be high enough to protect it from the more numerous minor flooding events.  The elevated building is now susceptible only to larger, less frequent flood events, reducing the probability of flood damage by about 60%.

 Notice here the block foundation and the brick veneer.  See how the foundation is bolted to the wood house-framing member.  This solid connection not only prevents the house from shaking or floating off its foundation, it provides the basis for a “continuous load path” that connects the house from foundation to roof. 

20. Continuous Load Path 
 “Continuous load path” is an engineering term that refers to a series of connections that allows forces, such as those created by shaking in an earthquake, to pass from one part of a structure to another and allow the building to move as a unit.  Without a continuous load path, there are “weak links” in a building’s connections.  Those weak spots are where failures are most likely to occur.  In an earthquake, for example, it would do little good to reinforce the connections in the building’s framing if the framing isn’t connected to the foundation.  In such a case, the house may not fall apart, just shake off the foundation. 

In this building, the poured concrete footing forms a solid connection between the ground and the concrete block foundation.  The foundation is bolted to the wood framing, which is tied together with metal connectors from the first floor to the third.  Finally, the walls are connected to the roof with metal connectors called “hurricane clips”.  These links form the building’s continuous load path.

21. High Wind Bracket
 The High Wind Bracket, invented by a graduate student researcher at the Clemson University Department of Civil Engineering, is a sturdy aluminum extrusion used to improve a building's connections.  Here, it secures a portion of the second floor to the first floor wall.  The bracket provides an alternative to removing a home's wallboard and installing metal clips.  It is simply lag screwed to individual framing members—in this case, the upper story floor joists and lower story walls—and covered with a bold cornice.  The bracket can be installed in various locations, most commonly to the roof truss and walls to secure the roof.  The bracket also resists damage from tree fall—tests at Clemson University show it to stop the descent of a 10-inch diameter pine.
 
 

Interior Water Use   Because of space limitations, the house has no kitchen or laundry to demonstrate some of the more significant water and energy conservation measures that can be taken in the typical home.  In this house these aspects of energy and water conservation are limited to a “low flow” 1.6 gallon per flush toilet and a “point of use” water heater.  Unlike a typical tank-type water heater, the “point-of-use” water heater, located just below the sink in the bathroom, heats water only as it is needed.  It prevents the need for continually re-heating excess water in a storage tank.  It also eliminates the waste of water that sits in the hot water line between a central water heater and the faucet, which cools between uses.

22. Geothermal Heating and Cooling System

 There are many methods now in use in the Charleston area to heat and cool homes.  Most of them use energy from electricity, natural or propane gas, or fuel oil to heat or cool the air that circulates throughout the house.  Geothermal “heat pump” systems use the temperature of the soil as its energy source.  Although not in common use at this time, geothermal systems are among the most energy-efficient systems available. 

A typical heat pump found in many homes extracts heat from the air outdoors in winter and brings it into the house for warming.  In summer it extracts heat from the air inside the house and vents it outdoors.  The geothermal heat pump works in the same way, only instead of an air-to-air heat exchange, it uses a system of buried plastic pipes circulating water to exchange heat with the earth. 

The system consists of an indoor heat exchanger, an underground water circulation system and a zoned air distribution duct system.  By having the heat exchanger housed indoors, weather-related deterioration is eliminated, thus extending its useful life.  Almost twenty-five hundred feet of 3/4-inch plastic pipe, with high heat transfer qualities, is buried under the landscaping and connected to the heat exchanger.  This closed-loop piping is buried in six 200 - foot deep by 4 - inch diameter wells dug along the back yard fence.  In Charleston, the ground temperature, below three feet, is approximately 68 degrees year around.  In the winter, heat is transferred from the ground to warm the house.  In the summer, heat is transferred from the house to the ground thus cooling the house. 

 Inside the house, heated or cooled air is distributed to the rooms through a zoned duct system.  Note that on the first floor, as a part of the flood proofing of the house, the ductwork and return are located at ceiling level.  All the ductwork in the house has interior insulation to keep the air hot or cold as it moves through the ductwork.  On the third floor, the ductwork is also insulated on the exterior due to high heat levels adjacent to the non-insulated part of the roof.  (Leaving the roof non-insulated was a compromise dictated by the need to demonstrate roof hazard retrofit.) 

The air distribution system consists of three zones, controlled by thermostats on each floor.  The system works with a series of electric controlled dampers that control the amount of air going to each zone. 
In most homes, perhaps the greatest waste of energy occurs when heated or cooled air is distributed to rooms that are not in use.  Much of this waste can now be eliminated by the use of programmable thermostats, that can heat or cool an individual zone at four to six separate settings per day, seven days per week, summer and winter. 

23, 24 and 25. Windows/Glazing
 Windows and doors, along with the roof and siding form what engineers call the “building envelope”.  This “envelope” is the building’s skin and serves as a barrier to things, such as rain, entering the building, and leaving the building, such as heat.  If for example, windows are broken in a hurricane, rainwater may enter the house damaging or destroying its contents.  Likewise, if the windows don’t effectively hold heat inside the building, heating costs will go up and resources will be wasted. 

At 113 Calhoun St. several types of windows have been used in order to demonstrate the range of available windows and how they perform as components of the building envelope.  In the first floor office and on the porch doors on both floors the original windows of the house were re-used for consistency with Board of Architectural Review (BAR) guidance governing buildings in the historic district.  The office windows [23] are single pane, “six over six”, true divided light windows, and are neither very storm resistant nor energy efficient.  Their lack of storm resistance is compensated for by hurricane shutters, as is discussed elsewhere.  To compensate for their energy inefficiency, interior acrylic insulating panels [23] held in place by magnetic frames have been installed in the first and third floor offices.  These panels function as interior “storm” windows and increase the energy efficiency of the windows substantially.  Heat loss in BTU’s is reduced by 77 % from 260 to 60.  These interior panels are consistent with BAR requirements in the historic district, but may also be useful in non-historic home and business applications.  In fact, the panels have been used to cover the exposed wall on the east wall of the building (left open to show the building framing and connectors) to improve energy efficiency there. 

Throughout the rest of the house double-pane “thermal” glazing has been used [24].  This type of glazing, more energy efficient than the single pane, has been used in double hung, single hung and casement window frames of wood and vinyl cladding.  The casement window on the second floor has a window film applied over the glass to improve the “R” value of the window [25].  Window film is marketed to homeowners for increased energy efficiency as well as hurricane protection.  While window film will likely hold together pieces of shattered glass in a hurricane situation, it is unlikely to be effective in preventing a breach in the building envelope in hurricane force winds. 
 

Here on the optional video clips, I'll take you inside the building at 113 Calhoun Street, where you will meet the 113 Calhoun Street Program Coordinator, Dick Dalla Mura.  You'll also see how we've strengthened the walls, and what kind of insulation we use in the building.

1. Enter and Meet Mr. Dalla Mura (392 KB)
2. Main Room and Chimney (328 KB)
3. First Floor: Building Connections (669 KB)
4. Head Upstairs (128 KB)
 

Now let's head on up to the Second Floor.