Atlantic Marine Corps Communities LLC: Laurel Bay
Background
Laurel Bay is a Marine Corps housing community in Beaufort, South Carolina that is comprised of 1077 single-family, detached residential homes built between 1957-1963. The largest problem these homes faced was leaky building envelopes and retrofitted leaky duct systems that made the mechanical system inefficient and over worked. Lend Lease renovated eight different buildings representative of the 1077 homes as part of this showcase project.
The average square footage of the pilot homes is 1,073 and they are wood framed construction with vinyl siding and electric heat.
Atlantic Marine Corps Communities LLC (AMCC) is a 50-year partnership created between the Department of the Navy and Lend Lease through the Military Privatization Act. AMCC will develop, build, renovate, finance, and manage more than 8,000 homes for the North Carolina Marine Corps Installations of MCAS Cherry Point, MCAS New River and MCB Camp Lejeune; the South Carolina Marine Corps Installations of MCAS Beaufort, MCRD Parris Island; in the Orange County New York enclave of Stewart Terrace; and in the Hampden County Massachusetts enclave of Westover. For more information, visit http://www.atlanticmcc.com/.
Solutions
The first priority was to increase the air tightness of the building envelope, followed by improvements to the thermal barrier at the ceiling, the deletion of voids in the thermal barrier, and increasing the attic insulation to R38. Next, replacing the duct system reduced the duct leakage to below 5%. Finally, the Ground Source Heat Pump unit was cleaned and optimized to ensure it achieves proper air flows at the return and supply grills.
Work on this project began in August 2012, and was completed in October 2012. The estimated savings per energy efficiency measure are as follows:
- Space Heating Savings - 35%
- Air Conditioned Savings - 55.5%
- Water Heating Savings - 68%
- Electric Base Load Savings - 13.7%
- HVAC Auxiliary Electric Savings - 17.8%
One of the more difficult aspects of this renovation was renovating the attic space of the Laurel Bay homes. The attic space had several abandoned mechanical systems such as fire sprinkler lines, a flume from the original oil burning furnace, and additional insulation added in previous renovations. Through the years, this added insulation has been pushed into the eaves blocking the soffit venting systems and not allowing the attic to vent. This trapped moist hot air in the attic also created additional loads on the cooling system.
To overcome these obstacles, the attic space was accessed from the roof with a series of 22”x36” holes, which were later repaired with the original shingles. This allowed Lend Lease to remove the old insulation and abandoned mechanical systems, and to access the ceiling lid to seal any penetrations. After all penetrations were sealed at the ceiling lid, new blown insulation was installed with the duct work to eliminate potential voids in the insulation. These repairs and installations created a consistent R38 thermal barrier between the ceiling lid and the attic.
Other Benefits
These Better Buildings Challenge showcase homes are part of the SCE&G Home Performance with Energy Star Program. In addition, the average Home Energy Yardstick score for all 8 homes went from 1.4 to 6.1 outperforming 74% of similar U.S. households.
Image Gallery
Stack effect and home leakage infiltration
