hurricane damage

Designing to mitigate hurricane losses

As we enter into hurricane season, many people ask, "How can I build to mitigate hurricane damage?" Historically, we have worried more about hurricanes with high winds but Hurricane Florence proved that category 1 storms can be just as disastrous. Eight people in South Carolina died, property damage was over $607 million, and more than 2,000 homes were lost to flooding.

When building a new house there are three critical concerns in the design and construction in hurricane prone areas that address the simultaneous impacts of wind, rain, and flooding.

Keep the building from blowing away

The building must be tied together from the roof rafters to the foundation. The most common method employs hurricane clips and tie rods. The building must be designed to withstand wind shear which can be accomplished with plywood sheathing if there are limited amount of openings in the walls. Walls with large openings often require steel framing to withstand the wind shear.

Windows and doors need to be protected from flying objects. The simplest but not the cheapest is to install impact rated windows and doors. Other options include hurricane rated shutters, PVC coated woven fabric such as Wayne Dalton’s Fabric-Shield® or plywood panels cut to fit the openings and fastened as per the building code.

The exterior finishes should be rated to withstand hurricane force winds and be installed securely to the structure as per the manufacturer’s recommendation to meet the tested installation.

Keep the rain out

Keeping rainwater out of the building is fairly straightforward but only if design decisions are made to address it. As the building scientist William Rose observed, “If it doesn’t get wet…it can’t leak.” Thus, large overhangs help keep the building dry by reducing the amount of water flowing down the walls by a minimum of 50%.

Field experience shows that water leakage around doors and windows is very common. Therefore, sill pans and flashing are essential. Flashing has two distinct purposes; it keeps water from getting into the wall through joints and it guides water back out of the wall when some leakage does occur.

All exterior cladding will allow some moisture to pass through. The best way to capture the water and direct it out of the wall system is with a drainage plane which is a waterproof layer on the exterior of the wall sheathing. For the drainage plane to work correctly there is an air gap to promote drying. Likewise, a secondary roofing membrane will keep water out if the primary roof material is compromised.

Crawl spaces must be sealed against water leakage, humid air infiltration and vapor permeation from the earth. Closed crawl spaces do not have vents to the exterior. They are insulated at the perimeter wall.

Drain water away from house by using gutters and sloping the ground away from the building.

Prevent flood damage

The most important consideration is to elevate the structure and mechanical systems to minimize its contact with flood water and a potential storm surge. The new flood maps that will soon be adopted in Beaufort County are lowering the flood heights in many areas. It may be prudent to place your house at the current higher requirement because of rising sea levels.

Crawl spaces located in a flood zone need hydro-static vents to prevent flood waters from collapsing foundation walls. The hydro-static vents will allow flood water to enter and exit the crawl space. Charleston based Flood Flaps® provide a tight seal for a closed crawl space.

Finally, use materials that tolerate soaking and can easily dry.

 


master bathroom

Master Bath renovation

Before & After

Here is a master bath renovation that we completed a couple of years ago in the Shrimp Pond house. The Shrimp Pond house is at Spring Island, South Carolina. We designed the house in the 90's, then new owners hired us for the Shrimp Pond Studio addition and for a remodel of the master bath.

See the side-by-side comparisons in this master bath renovation:

Shower:

The addition of the round window in the shower and the new tile make it so much brighter and prettier.

Vanity:

master bath floating vanity

The floating vanity gives the space a contemporary feel. It's a cleaner aesthetic, and easier to clean too!

Tub:

free standing tub

The tub area is updated by swapping the drop in tub for a free standing tub, new tile and losing that dated brick accent wall.


Rooftop Solar in South Carolina

The state legislature passed a bill this week that signals a win for rooftop solar in South Carolina! It's called the SC Energy Freedom Act. The bill will allow the expansion of the solar market, both large scale and for residential installations.

Solar panels on custom spring island house
This house on Spring Island has a 10.50 kW solar array- see the completed project here.

In 2014, a state law passed that made South Carolina a viable market for solar power by enacting tax credits and net-metering requirements. To appease the power companies, the 2014 law included restrictions (or caps) on the amount of rooftop solar allowed in the service areas of SCE&G (now Dominion Energy) & Duke Power. These caps were reached this Spring. Without the bill that passed this week, the solar market would have collapsed in SC because net-metering would no longer have the same benefits.

What is Net-metering?

Net-metering is the process by which a home with rooftop solar sells excess energy to the utility company, and draws energy from the grid when the solar system is not producing energy (like at night). The customer will always have electricity, provided the grid is functioning properly. The new legislation requires that the utility companies buy power from customers producing excess energy at the same rate that they sell to consumers.

What about battery storage for solar energy?

Batteries like the Tesla Powerwall can be connected to solar panels to store excess energy. At times when the solar panels are not producing energy, the consumer can tap into the energy stored in the battery. These batteries are really cool, but they may not be practical for the average consumer. They are expensive and one battery probably does not have the capacity to power a whole house. The technology is rapidly advancing, and battery backup may soon be a more practical option. We have a number of clients who have installed solar connected batteries in order to keep essential appliances and lights on in the event of power failure. In our hurricane prone area, I think this approach is smart. Often, the days following a major storm are sunny, but it may take utility companies days to weeks to restore power. A house with a solar array + battery would be sitting pretty!

Two Tesla Powerwall2 batteries at a recent project
Two Tesla Powerwall2 batteries at a recent project

Net-metering is an essential piece of the growth of solar power in South Carolina. I congratulate the legislators that championed this bill. Alternative, renewable energy will continue to be a sound choice for South Carolinian's; both for our wallets and for our environment!