NAHB Research Center and Habitat

by Joel Barkman

Last week I introduced you to the National Association of Home Builders (NAHB) Research Center and the work that we are doing with older homes in the area. While the story I am about to share with does not take place on our own doorstep, it does take place in our backyard.

Twelve 50-year-old homes have been renovated by Habitat for Humanity of Montgomery County, Md. — with technical assistance from the NAHB Research Center — to significantly improve their energy efficiency while keeping the construction costs affordable.

Most of the homes are 1950s-era ramblers with block and brick facade construction and basement foundations.

Project goals included enhancing safety, improving durability, lowering monthly utility bills and adhering to a tight schedule and minimal budget — as well as taking into account Habitat's usual practice of using volunteer laborers working in six-hour shifts.

Habitat partnered with the NAHB Research Center through the Department of Energy's (DOE's) Building America program. Its job was to observe the remodeling process and details, recommend additional energy enhancements, help identify the right products and materials for the volunteer laborers, model potential energy savings, verify improvements with before-and-after testing where possible and document the process so it could be repeated in similar kinds of homes — perhaps in homes here in Fauquier County.

Habitat trained the volunteers and segmented the work into discrete tasks taking three to four hours each and also made sure that all necessary materials and supplies were ready — ensuring timely delivery for quicker occupancy.

For all the homes, Habitat removed interior wall finishes from exterior walls, adding or increasing insulation in the foundation, above-grade walls and ceiling; upgrading electrical systems, including rewiring; replacing most plumbing and all fixtures; and evaluating HVAC equipment and ducts.

Following recommendations from the NAHB Research Center to enhance energy efficiency, durability and indoor air quality, the improvements included:

Replacing windows with the highest efficiency that the budget would allow and taking care to install them according to the manufacturer's recommendations
Adding air-sealing details at various locations — including roof/wall intersections, crawlspace walls and soffits
Relocating supply and return ducts from exterior walls to the floor
Ensuring adequate and simplified return air paths for all rooms for enhanced comfort and indoor air quality
Installing programmable thermostats
Ducting kitchen and bath exhaust fans to the outdoors
Installing Energy Star-rated appliances and light bulbs
Broom sweeping all areas of the home after demolition to improve the effectiveness of the air sealing, helping to improve worker safety and indoor environmental quality
Confirming that the downspouts and grading adequately directed rain water away from the house and that sump pumps were operating properly
Adding exterior insulation where appropriate

The NAHB Research Center found that the most significant gains in energy performance came from improvements to wall insulation.

For the 10 homes constructed of block, the original R-4.7 walls were upgraded to whole-wall R-20 by removing the drywall, attaching 1-inch rigid foam to the block and then constructing a 2x4 wall on the interior of the rigid foam, air-sealing the top and bottom, insulating the 2x4 cavity with R-13 insulation and finishing by installing drywall and painting the interior walls.

Wall insulation details were also developed for the homes that were wood-framed. Where the siding was replaced, the volunteers added one inch of exterior rigid insulation to increase the whole-wall R-value from R-11.8 to R-17.4.

Another key was air sealing. While the Research Center could find air leakage paths for individual homes through blower-door testing and other measures, the overall goal of the project was to determine common problem areas to successfully air-seal multiple homes without having to test every one.

The Research Center developed a list of good candidates for air sealing, including the intersections of floor and foundation walls and the ceiling and walls; rim/band joist areas; wire and pipe plate penetrations; sloped ceilings; balloon-framed gable end walls and any gable walls adjacent to the main house walls in split-level designs; cantilevered floors; attic hatch covers; chases and chimneys; wall sheathing; and any new openings created by the retrofit.

"The 12 remodels successfully addressed and installed more insulation in exterior walls to increase the energy efficiency of these homes," said the Research Center's program manager.

"The energy performance shows that meeting current energy code is achievable through whole-house remodeling of 1950s era homes."

Habitat and the NAHB Research Center now are studying best practices, details and training to determine specific ways to increase energy efficiency and durability for each remodeled house.

The purchases of the homes and renovation costs were supported through a special grant program from the county, and Habitat will pay the grant back when it sells the homes. The costs were kept down because of Habitat's network of suppliers and volunteers.

The good news, according to the Research Center's program manager, is that "Habitat Montgomery County is planning additional renovation projects that could provide the opportunity to advance the development of energy performance remodeling for affordable homes in Maryland."

If you would like to learn how you can support our local Habitat please visit www.fauquierhabitat.org or — just "Ask a Builder."

As always e-mail your questions or comments to joel@goldenrulebuilders.com or write to "Ask a Builder" at P.O. box 294, Catlett, VA 20119.

Barkman is past president of the Fauquier Chapter of The Northern Virginia Building Industry Association.

Read Joel's column weekly in the