Article No: 244

2008-09-29 10:27:53
Efficient, Sturdy, and Purdy Too
By: Steve Habel

When it comes to the construction of homes in Florida, there are obstacles aplenty in finding the proper balance between efficiency and stoutness—none more than the combination of oft-tropical weather and the occasional home-busting winds and water of a hurricane.

The good news is that balance can be attained. A continuing example of such is the Madera community of Gainsville, a “green” neighborhood that was expected and has reached new and higher standards for resource efficiency, due to the use of insulating concrete forms (ICFs) in the community’s model center and in many of its existing and planned homes.

Situated on a fully wooded 44-acre site adjacent to the University of Florida in Gainesville, Madera is a cooperative effort between the University of Florida, developer Greentrust, LLC, custom homebuilder Carter Construction, and Steven Winter Associates, a Department of Education Building America Team. The long-term goals of this pioneering effort include both ecological stewardship and environmental education. The 88 homes master-planned for Madera are designed as exemplars of green, cost-effective construction practices. All of the community’s residences are constructed to exceed conventional performance standards in Florida. Upgrade packages are offered to homeowners to further boost their homes’ performance in energy and water efficiency and termite resistance.

The use of ICFs in the construction of homes is key to the community’s goals. Florida-based ECO-Block, the nation’s second-leading provider of ICFs, stepped up to provide its environmentally friendly product for utilization in Madera. “ICFs are a natural fit for Madera,” says Vera Novak, an environmental specialist for ECO-Block. “Not only does the use of ICFs save trees during the construction phases, its superior insulation abilities continue to offer dividends year after year. Homeowners can save up to 50 percent annually while keeping their homes warm in winter and cool in summer.”
Constructing a home with ICFs has multiple advantages to both the homeowner and the environment as it consistently saves in time, money, and energy resources. A study backed by the Portland Cement Association found that homes built with ICF exterior walls need an estimated 44 percent less energy to heat and 32 percent less energy to cool than their wood-frame counterparts. An average-size home can save up to 41 trees if concrete products, such as ICF exterior walls, are used in place of wood products. In addition, because concrete is inert, non-toxic, and produced from abundant natural and recycled materials, the cost of building a concrete home is comparable to one built with wood. Experienced crews report that building ICF homes can take less time than using wood-frame construction. Several steps are eliminated-such as sheathing and insulating the exterior walls-that are necessary with wood-frame construction. The use of concrete also helps ensure durability.

All aspects were used to their fullest at Madera. “We support the use of sound designs, products, and construction technologies to build high-quality, durable homes that have low maintenance requirements and use energy and water efficiently,” says Dr. Pierce Jones, who directs the Florida Energy Extension Service at the University of Florida. “Madera is a great opportunity to work with builders and product manufacturers to put these ideas into action. As a result homebuyers in Madera can expect their homes to be environmentally friendly and to have significantly lower utility bills.”

During the 20th Century, Florida was second only to Texas in the number of direct hurricane hits from major storms, suffering 57 total categorized storms with 24 of those being categories 3, 4, and 5 with winds of 110 mph and higher. That means homeowners somewhere in Florida were hit by a hurricane every other year. More importantly, major storms, which account for only 20 percent of all tropical storms yet cause four times as much property damage, came every four years.

One way of ensuring a new home’s safety is to build it using durable, hurricane-resistant construction systems. A great example is use of ICFs, which are permanent forms for cast-in-place concrete walls. By leaving the forms in place, a homeowner can reap extra benefits from the insulating materials.

ICFs are expanded polystyrene panels that easily assemble to create walls of virtually any thickness, from four-inch to two-foot increments. The space between the panels is filled with concrete that cures and hardens into a monolithic reinforced concrete wall of incredible strength. These extremely strong concrete walls are able to withstand winds up to 250 mph and also offer a three-hour fire protection. Added benefits are sound suppression and versatility in design.

By 2015, ICF homes are expected to make up 15-25 percent of all new homes built as more and more homeowners are looking for ways to increase energy savings and structural integrity to withstand natural disasters.

ICFs were chosen for Madera primarily for their energy efficiency. ICF walls act as an energy reservoir that reduces temperature fluctuations and energy transfer. The concrete walls of an ICF home have a high thermal mass, which means that the heat slowly builds up in the wall, as the sun shines on it during the day, to release it into the interior during the night. This ‘thermal mass effect,’ or ability to store heat and release it when needed, acts as a buffer for the interior of the home from the extremes of outdoor air temperature and therefore contributes to the energy savings.

Also contributing to energy savings, is the fact that an ICF home is extremely air-tight and the ICF walls have consistent insulation throughout the home. This is because there are no joints existing between walls, or walls and floors, preventing conditioned air leaks from the interior to the exterior of the home. The outside air stays out and the inside air stays in. “The insulating effect is better, if not double, than that in normal homes,” Dr. Jones says.

Madera’s environmental aspect has been well received by the Gainesville area’s utility provider. Gainesville Regional Utilities (GRU) is paying the owners of one of the community’s energy-efficient homes for helping reduce greenhouse gas emissions. GRU says the reductions at this one home helped the utility’s power plants avoid releasing about 8.6 metric tons of the greenhouse emissions, which many experts believe cause climate change. The utility paid $86 to homeowners Linda Bartoshuk and her husband, Charles Sommerfield, for credits representative of those reductions.

The four-bedroom, two-bath model home was built in 2004 and sold to Bartoshuk and Sommerfield for $445,000 in 2006. Researcher Nicholas Taylor studied other area homes built around the same time and determined their average energy use in 2007. The study found the Madera home used half as much energy and its occupants saved $900 on utility bills.