1. Permeable Pavers
 An important goal in both flood mitigation and water management is minimizing “run-off”.  At 113 Calhoun St. the permeable paving system helps to hold rainwater on site, reducing run-off.  It is a multi-layered system consisting of a bed of sand, on which a layer of pea gravel was added.  On top of the gravel, paving stones have been set with a 10 percent open joint area to allow drainage for rain and storm water into the sand and gravel bed for slow seepage into the water table.  Non-permeable pavement, like standard concrete and asphalt, allows water to drain into roadways then into storm water drains and eventually into marshes, streams, lakes and rivers.  This run-off carries fertilizers, pesticides, oil residue from cars and other pollutants into our state’s waters. 

The paving system at 113 Calhoun Street has an 8,000 lb. per square inch compressive strength making it suitable for heavy vehicles.  It also meets Americans With Disabilities Act (ADA) requirements for handicap accessibility. 

2. Landscape
 The landscaping for 113 Calhoun St. was designed with sustainability in mind.  Generally, the plants selected are either native to this area or have been found to thrive in local conditions.  The use of native and locally conditioned plant material reduces the need for fertilizers, pesticides and irrigation water, saving money and resources.  When fully “grown in” the garden is designed to thrive on rainwater alone.  However, a drip irrigation system has been installed to provide supplemental water during the grow-in period and in times of drought.  Drip irrigation is one of the most efficient methods of watering, delivering small amounts of water directly where it is needed most and eliminating run-off typical of many sprinkler systems.  To further conserve water, reduce weeds and keep the soil cool in summer, hardwood mulch has been placed on the ground around the plants. 

For convenient identification, all the individual plants - annuals, perennials, shrubs and trees - are labeled with their common and Latin names. 

3. Pest Control
 In Charleston and many other areas of the country, termite infestation is an enormous problem, causing billions of dollars in damage to homes every year.  In this area there are two kinds of termites, subterranean and Formosan.  The traditional way to protect homes from termite infestation is to soak pesticides into the soil around the foundation and under the house.  At 113 Calhoun St., a newer method is being used.  Green caps that look like sprinkler heads throughout the landscape mark the site of “baiting stations”.  The baiting stations contain untreated wood to attract any termites invading the area near the house.  A technician checks the wood in the baiting station regularly for signs of termite activity.  If termites are present in the baiting station, the wood is replaced with an insecticide that slowly kills the termites until the colony is eliminated.  The insecticide works by stopping the termite’s molting process so they cannot develop into wood eating adults and the colony dies. 
 

4. Cypress Siding
The original house siding was of cypress. Surprisingly, despite years of neglect, most of the cypress siding was in very good shape.  This speaks well not only for the quality of the wood, but also for the selection of materials by the original builders.  Because of its very good condition, about 90% of the original siding was retained.  The siding that had to be replaced due to extensive cracking and rot was replaced by cedar siding.  Due to cost and a closer match with the weathered look of the cypress, cedar was the practical choice. 
 

5. Hardiplank Siding
Another, even less traditional, siding material was selected for use on the rear of the building, part of the west-side, the first floor piazza ceiling and on the front gable end.  Hardiplank a saw dust and cement product, was selected to demonstrate a sustainable alternative to wood.   It is composed of Portland cement, ground sand, cellulose fiber, select additives and water.  It contains no asbestos, fiberglass or formaldehyde, and is non-combustible.  It is a highly sustainable material because of its resistance to termites and rot and high retention of paint.  Please note that the Charleston Board of Architectural Review (BAR) does not currently allow Hardiplank to be used on homes within the historic district.  An exception was made for this project due to its educational nature. 

6 and 7. Porches / Piazzas
It is important that all elements of a building’s structure be “tied together”.  This provides added strength and stability.  Often insufficient attention is paid in the design and construction process to how porches and decks are attached to the main part of the building.  Please notice the cutaways at the porch columns that reveal metal ties connecting the first floor porch to the foundation below and the second floor porch above.  In porch/deck designs without ties, high winds and storm surge can literally tear the structure away from the main part of the building creating gaping holes exposing the structure to extreme wind and water damage.  In Charleston, this kind of damage occurs mostly on barrier islands, but may occur in other areas with substantial exposure to high winds, like along rivers and marshes. 

The original wooden porch columns were found unsuitable for re-use in the renovation of the building.  The new columns are a cement and fiber composite material, like the Hardi-plank siding used on the back of the house.  These are also considered to be “sustainable” building materials because of their invulnerability to termite infestation, and longer usable life. 

Window Protection
There are many ways to protect windows from damage from wind pressure and wind borne debris.  A variety of methods and materials have been used in the house to illustrate the range of options available to the homeowner.  They include:

8. Traditional Wood Colonial Shutters
 Traditional wood shutters were used on the first story of the front of the house.  This is currently the only type of window covering that is approved by the BAR for use in the historic district.  While not ideal for protecting against wind borne debris impacts, these shutters do offer substantially greater protection than no shutters at all. 

To provide these wood shutters with added resistance to penetration, we have installed hardened fiberglass backings that only show when the shutters are closed.  The fiberglass backing helps the traditional wood shutters to exceed the Dad County debris impact-resistance standard.  Because the panels are not visible when the shutters are open, they may be acceptable for use in historic districts.  Local Boards of Architectural Review should be consulted before installation. 

9. Aluminum Colonial Shutters
 Aluminum shutters designed to look like traditional wood shutters have been installed on the second and third floor front windows.  These heavy-duty shutters provide much better protection against wind borne debris than do either wood or plastic shutters.  These shutters were custom made for the project to demonstrate that it is possible to manufacture improved window protection that is consistent with the need to maintain the historical “look” of the area.  They are not currently available on the market. 

10. PVC Colonial Shutters
 PVC shutters fabricated to look like traditional wood shutters have been installed on the first and second floor windows on the west-side of the house (the side with the porches).  These shutters may not offer much more protection than the wood shutters, but they are easier to maintain.
 
 
 
 

11. Roll Down Aluminum Window Coverings
 Roll downs, as they are called, have been installed on the first floor piazza.  Hidden in the piazza ceiling, they are used to protect the door openings.  They are closed manually with a crank from the porch.  They are also found on the second floor rear window.  There they are closed with a crank from inside the house.  This kind of shutter is also available with electronic controls. 
 
 
 

12. Polycarbonate “Bubbles”
 The polycarbonate bubbles covering the first floor rear window and the second floor piazza doors are made from the same material as the canopies of U.S. Air Force F-16 fighter airplanes.  According to their manufacturer they will withstand an impact equivalent to a 2”x4” board travelling greater than 50 miles per hour.  Their outward curve helps ensure that debris hitting them will only strike a glancing blow.  One big advantage of this alternative is that because they are “see through” they can be installed at the beginning of hurricane season and left up until it’s over.  It may be an especially good option for the owners of rental property and other absentee owners. 
 
 

13. Impact Resistant Glass
 Impact resistant glass has been installed on the rear facing doors on the two piazzas as well as on the dormer windows on the third floor.  This glass meets the Miami-Dade code standard for impact resistance.  That is, it will withstand the impact of a 9-pound, 2”x4” board travelling at 34 miles per hour.  Although this particular code is no longer in effect, it is still a very high standard, sometimes exceeding the impact resistance of walls.  According to the standard, the glass may break but not allow the penetration of water or debris.  A disadvantage of this form of protection is the high replacement cost of windows and doors.  An advantage is that it may be used in very high or otherwise hard to reach windows and skylights that can be very difficult to cover. 

14. Corrugated Aluminum Window Coverings
 Corrugated aluminum window coverings are perhaps the most cost effective option shown on the house that is available to the homeowner living outside the historic district.  Notice when you go inside the house that these shutters do not require a ladder to install.  They are designed for use with double hung windows to be installed from the inside.  This is an important safety feature, eliminating the need to climb and balance on a ladder up to 30 feet in the air, possibly under windy conditions.  Corrugated aluminum shutters have the added advantage of not warping when stored as plywood can when exposed to heat and humidity over long periods of time. 
 
 
 
 

Plywood Window Coverings   While there are no plywood coverings installed on the house, plywood remains the most cost-effective form of window and door protection available.  Designs for plywood window and door coverings are available from APA-The Engineered Wood Association on their web site <www.apawood.org> free or via mail for $5.00 a set.  While low cost is the advantage of plywood, it has several disadvantages.  For example, plywood is heavy and dangerous to install from a ladder on second and third stories.  It can also warp in storage in hot, humid conditions.

Window Film / Adhesive Tape
 There is no window film installed in the house for storm protection.  In the view of experts consulted in this project, window film offers very limited storm protection for most residential uses.  It is, however, a useful product for energy conservation, offering protection against the penetration of ultraviolet light and the heat of the sun (see 25, Windows and Glazing).  Window film can be an excellent option for some commercial applications. 

 Although you may still hear advice about taping windows, this is not a recommended form of window protection.  It is, in fact, useless for storm protection.  Tape has the further disadvantage of being extremely difficult to remove once it has been baked-on by the sun. 

15 and 16. Roofing Materials
In keeping with the look of buildings in the historic district, a standing seam metal roof was selected for the house.  Although copper is the material of choice for metal roofs, due to cost considerations an alloy called Terne metal was used on this project.  Because no high wind standards exist for metal roofs, Clemson engineers worked with the manufacturer to devise a fastener schedule which will improve the wind resistance of the roof.  Based on manufacturer recommendations, the metal roof was installed directly on top of the plywood decking, without the usual underlayment. 

The original planked roof decking was severely damaged by Hurricane Hugo and was replaced in its entirety with 5/8-inch plywood sheets.  The roof decking is attached with ring-shank nails, supplemented with #8, 2-inch wood screws.  Clemson University laboratory research has shown that using screws to supplement nails in roof attachment gives a roof five times greater capacity to withstand being pulled-off by hurricane winds. 

There is a small section of roof, not easily seen from ground level, with asphalt shingles [16].  The shingles were installed according to manufacturer specifications, using 6 nails per 3-tab shingle.  For added protection against wind uplift, roofing cement was “hand tabbed” under each shingle to improve their adhesion. 
 
 

Utilities
All electric, computer and telephone lines to the building have been installed underground.  Unlike lines that attach to the sides of building, underground lines are less susceptible to wind damage. 

You can also come along with me (via video) around the outside of 113 Calhoun Street, first looking at the foundation, and then at the window protection used in the building.

1. Foundation (760 KB)
2. Front Exterior (488 KB)
3. West Exterior (272 KB)
4. Piazza: French Doors (424 KB)
5. Piazza: Impact-resistant Glass (232 KB)
6. Back Exterior (280 KB)
7. East Exterior (120 KB)
 

Ready to go to the First Floor?