Mold can be a costly and potentially unhealthy nightmare for homeowners. In recent years, widespread concerns about mold growth in homes have led to the development of mold-resistant building products, including mold-resistant drywall.
Jeff Wilson has always wanted to build a green dream home. "It was going to be this super-high efficient, solar-powered, off-the-grid house — those were my goals," says Wilson, 42, of days when he would study plans for building an earth-sheltered concrete home.
Instead, he took quite a different path when his family moved into a 70-year-old Cape Cod home in the rural college town of Athens, Ohio. "We found a dream house in the rough," he says, describing its proximity to the elementary school, farmers' market and local shops. "Then, we decided to rebuild it."
Specifically, Jeff embarked on a journey to give his home the ultimate energy efficient treatment: a Deep Energy Retrofit (DER) that involved everything from beefing up insulation to installing solar panels. He converted a leaky, uncomfortable home that needed some TLC into a functional, healthy environment for his family — one that eventually will not cost him a dime to heat and cool.
"Getting a handle on old homes and retrofitting them is something that someone needed to tackle, and I felt it was a place where I could lend my voice," Jeff says of the yearlong project.
The Decision to Retrofit
New homes are already more energy efficient than their ancestors, and increasingly stringent energy and building codes are pushing construction in a better direction. Retrofitting an old home is more of a challenge, which Jeff proves in his DER effort.
"The hardest part is seeing the project as one big picture in the beginning and working to get through the everyday," he says, describing the stresses his family endured while living under work-in-progress conditions. The worst nights were when harsh storms hit while the roof was in progress, covered only by a tarp. Water rushed into the home, leaving Jeff with damage to patch and sleepless nights wondering what would come next.
His wife, Sherri, was an equal partner in the DER project. And his children absorbed their changing environment, watching solar panels go up on the roof and standing by while Mom and Dad used spray foam to insulate the house.
"I hope they get out of this the same thing I got out of my experiences growing up — I really got a life's purpose out of what my father and grandfather were interested in," he says. Jeff's maternal great-grandfather was an architect/civil engineer and solar power enthusiast. His father was a businessman/engineer who was deeply interested in passive energy: how to "fix" a home to use less power. Together, they designed Jeff's childhood home, and the process made such an impact on Jeff that decades later he decided to pursue this DER project.
Of course, all those dreamy ideas were interrupted by a rude awakening once Jeff began stripping the first pieces of aluminum siding off his home. The project had officially started and there was no going back. "It's like a Band-Aid," Jeff says of taking on a large-scale project all at once. "You have to pull it off fast and get it over with."
Jeff's DER Checklist
Initial improvements to the home before the DER began included an upgrade of the HVAC system, some new windows and a door, and blown-in insulation. Jeff had a long way to go to achieve his goals, so he began by getting a Home Energy Rating System (HERS) test conducted by a certified rater.
HERS Test: A daylong visit from the HERS rater covered every mechanical aspect of the home (HVAC, appliances, lighting) and its envelope (windows, doors, insulation, roof). The rater conducted a blower door test to test the leakiness of the house, and a duct test to find additional leaks. He checked electrical outlets for leaks and compiled all this information into a handy report with charts.
The Wilsons scored an 87 HERS rating, with 100 being the HERS baseline. Higher than 100 means a home is relatively inefficient; a score of zero means the home uses only the energy it creates, such as through solar or wind power. That net-zero score is exactly what Wilson is after in his DER plan. Wilson used the energy audit report as a blueprint to improve every aspect of his home to complete a full DER.
A "curtain wall" was built around the original home to improve efficiency. It consisted of several inches of spray-foam insulation, studs, sheathing and house wrap. The new garage/addition received the same treatment, except additional R-13 fiberglass batting was added to the interior walls.
Jeff chose two different green products for his roof. On the back of the home where solar panels were installed, he opted for WeatherBond Pro Weld-Free TPO (thermoplastic polyolefin), a heavy-duty rubber roof that is white to reflect the sun and prevent heat from entering the attic. The back shed roof was raised to a nearly flat plane to support the solar panels. The front roof was covered with EcoStar recycled rubber roofing, which resembles slate. Before laying roofing, Jeff used spray-foam insulation and radiant-barrier sheathing.
The garage/workshop area was increased by seven feet and a loft was created to house a roomy office that could be converted into an apartment. The structure sits on a "floating" concrete slab that is insulated on all sides by four inches of foam board. The lumber used to build the structure was sustainably harvested, and the walls got the DER air-seal treatment. The garage door is R-19 compared to standard R-4 or R-6 doors that leak energy.
Solar panels take up one quarter of Jeff's roof surface; they are placed discreetly on the back roof and not visible from the street. The 4,000 kilowatt system will reduce electric bills to nothing and allow Jeff to sell power back to the utility company. He hopes the additional power will eventually offset natural gas bills.
Wrapping Up the Project
Jeff will invite the HERS rater to perform another energy audit in the fall to find out whether he met his goals to drastically improve the efficiency of his home. Before the DER, the home's airflow leaks measured 2,800 cfm. A "tight" house averages 1,200 cfm. The HERS rater's home is 600 cfm. "I am aiming to get my house as close to that as possible," Jeff says.
Regardless, Jeff says, the DER project met his expectations. "We were aiming for a more comfortable, less-expensive-to-run, healthier home," he says.
He doesn't expect results overnight, though he already has cut his energy bills by more than half. By December, the solar savings will kick in and Jeff will be earning money back from the utility company.
Jeff shelled out $50,000 to finance the DER and received donations in materials along the way. (For more detailed job-costing, see What It Costs to "Green" an Existing House). There's still minor work to do and projects Jeff will take on inside the home, but the DER plan is complete.
"It's empowering to take a home that was formerly using fossil fuel energy and turn it into a net producer of clean energy," he says. "That probably has a bigger impact on the environment than running out and building the perfect brand-new green home."
Mold thrives in moist, damp environments like basements and crawlspaces, where all it needs to thrive is a water source, oxygen and organic material. Often, the latter is provided by drywall that's been exposed to moisture — in this scenario, the paper covering on the drywall can become an all-you-can-eat buffet for all manner of mold species. Mold-resistant drywall was developed specifically to address this common problem.
The chief innovation in mold-resistant drywall is the substitution of fiberglass mat for the paper facing used in traditional drywall. This way, moisture cannot adhere to the organic paper material, creating an attractive food source for mold. In addition to mold-resistant drywall, greenboard is often used in bathrooms and showers as a mold-preventative building material. Though it's less effective at preventing mold than mold-resistant drywall, it's generally also less expensive.
Mold removal and remediation can be a time-consuming, expensive process, and if you do it yourself, it can even present health risks. If you're interested in keeping your home healthy by lessening the risk of mold in your home, you may want to invest in prevention up front, in the form of mold-resistant drywall.
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- Common Types of Mold in Homes
- Control Mold Through Water Management
- Black Mold Symptoms and Health Effects
- How to Remove Black Mold
- Mold-Resistant Paint