Along with a slew of awards and nicely-done integration of green building and historic preservation, this custom retrofit has some great lessons learned.
Honoring an amazing 100-year context
This renovation project took place in the in Atlanta, Georgia, and entailed the expansion and major renovation of the entire structure. Druid Hills was designed by , designer of ). The neighborhood was the location for the filming of . The house was built in 1918 and had to go through a historic preservation committee approval before construction began. Shortly before construction was scheduled to start, a 120-year-old oak tree fell and damaged the rear of the house, including many of the clay roof tiles. All the salvageable clay tiles were reused, along with several thousand additional vintage tiles purchased that matched the house perfectly. We thought the existing buff-colored brick on the house was going to be hard to match, so the original plan was to stain the new brick to match the existing. But when delivered, the new brick was a perfect match for the original brick.
Efficiency by design
One core concept of the project was to reuse as much of the existing structure as possible while expanding the house considerably. Starting with three bedrooms and two baths, the goal was to expand to five bedrooms, including a large master suite, and to redo the kitchen in such a way that a state-of-the-art family room could be added. The solution was to convert the entire attic to living space, adding just three dormers, and to add just a very small addition to reconfigure the kitchen into the new family room. Except for the small addition, the exterior wall surface on the first floor remains unchanged. A screened porch, a new garage, and completely upgraded systems and equipment rounded out this project.
Efficiency in materials
One key job site practice employed throughout the project was extensive reuse and recycling (scroll far right). All the unpainted wood from the site was reused on other projects or ground into mulch and used for erosion control. Extra bricks and broken roof tile were ground on site and used as gravel below the driveway. The concrete removed from the drive was hauled to a recycling plant and ground into base for underneath the rest of the new driveway. Most of the cabinets, counters, plumbing, and electrical fixtures were recycled through individuals and organizations. Job site recycling included all drink containers and corrugated cardboard.
Low-VOC paint and floor finishes, and MDF and finger-jointed wood products were used throughout the home’s interior. And despite its environmental stigma, PVC was selected for the exterior trim based on durability and moisture resistance.
Our focus on materials certainly did not come at the expense of energy efficiency. We dropped the air infiltration rate by two-thirds. By my best estimates using 4-month before and after data (including adjustments for square footage, heating degree days, and cooling degree days), our work reduced heat and hot water by 68% and cooling, lighting, and plug loads by 54%.
As the Lakesideca Curmudgeon, I am exceptionally good at ferreting out lessons learned.
Sound transmission: Sure wish we had done more acoustical separation between the first and second floors while we had things pretty much opened up. We went back and insulated the knee walls after the fact, but that did not help as much as we had hoped.
West glazing: We completed the remodeling design before the 100-year-old oak tree fell in the back yard, exposing two sets of west-facing windows. We should have designed shading for those windows on the fly.
Hot water: We should have taken into account hot-water distribution in laying out rooms and actual runs because the lack of structured plumbing means lots of long piping runs and demand pumps. This lack of design included the function of both tankless water heaters.
First floor tankless water heater: We could not locate it near the bathroom as planned because we could not vent it there. So it ended up on the opposite side of the basement, requiring yet another on-demand pump.
2nd floor tankless water heater: This was designed with ½” return loop, but when the on-demand pump was installed, there was too much resistance on the return line. We had to relocate the pump to another part of house, and then a jump between the ¾” hot and cold lines worked fine.
Too darn big: We kept the formal living room, dining room, and a small den, all of which are basically unused almost all the time. We could have and should have pulled more existing space into the reconfiguration and brought the total square footage of the project down a lot.
Those bloody occupants! I walked upstairs once on a nice day (about 68 degrees) and the hallway was about 90 degrees. I went into my stepson’s room, where the thermostat for that part of the house was located, and he had the windows wide open and the heat set to about 72, causing the heat to run continuously just to keep up in his room. You can't get new kids, so we need systems that give feedback to outsmart our families.
General Specs and Team
- CFLs in all recessed lights
- fan timers, occupancy sensors
- daylighting with skylights and interior windows
- Furnace: Amana 94% AFUE Gas Forced Air
- AC: 14 SEER
- Windows: Insulated argon filled, U=.26, SHGC = .35
- Air tightness: ACH ("natural" Before) = .76; ACH ("natural" After) = .26
Indoor Air Quality
Green Materials and Resource Efficiency
- reused clay roof tiles
- reused existing brick
- recycled concrete & damaged brick
- advanced framing throughout
- engineered framing members
- HERS score: 72 (old system)
- 2006 Environmental Design and Construction Magazine Excellence in Design Award Finalist