LEED BD+C: Homes v3 - LEED 2008
Eco Modern Flats
LEED Platinum 2011
Goals and motivations
What were the top overarching goals and objectives?
Our first goal, before we even identified this particular project, was to find a great infill site. We knew that there were people who wanted to live in a walkable area and wanted access to the trail system, but who couldn't find suitable housing choices. We knew that there were people who truly wanted to live in a community that was more than just a place to live. That community feeling is something that is fostered by a walkable location.
When we found the site, our main goal was to cut utility consumption. These apartments are master-metered, so as the developer, energy and water efficiency affects our bottom line. The second goal, and one that's personally important to me, is indoor air quality. It's my conviction that it's wrong to fill an apartment with cheap and toxic materials when alternatives are available at a similar cost. Fayetteville is a progressive market, so we knew that there was a market for healthier apartments; before ECO, there were almost no healthy choices for renters.
The ECO-Catalog was designed for a broad community focus. The publication highlighted 32 sustainability strategies in use at ECO Modern Flats. The full catalog is available at ecomodernflats.com/about/eco_catalog
Another goal-to serve as an educational resource-emerged as we realized what a different project this was, and how much we had to offer in terms of inspiration, not just to multi-family developers and renters, but to homeowners.
The top three goals for this project were:
- Building Reuse: To maintain as much of the integrity of the existing structure as possible. The building frame was constructed of concrete masonry units and precast concrete floors and roof deck. It was our goal to utilize as much of the building structure as possible and work with the existing floor plans. The original design of the building included a four foot wide chase that runs between each of the four buildings and all the units back up to that opening. This means that all the piping and ductwork from the kitchen and bathrooms come into that central chase. If the original architects had not provided that design feature for dealing with the ongoing maintenance of those systems, we would have been tearing out concrete structure to access them which would really have made this project impossible.
- Energy Efficiency: All mechanical systems and building envelope systems where inefficient and needed to be improved or replaced. We replaced the HVAC system with high-efficiency, mini-split systems; replaced all windows with ENERGY STAR windows; furred out masonry block walls and sprayed them with closed-cell foam; and installed a new cool roof with rigid poly iso insulation.
- Sustainable materials: The owners and the design team focused on selecting materials that were recycled, regional, low-emitting, and durable. We polished the concrete floors to reduce the need to replace and maintain them; used low/no-VOC paints throughout the building for improved indoor air quality; selected recycled and regional construction materials; and reused existing materials when feasible.
ECO Modern Flats surrounds a saltwater pool. The former laundry is now the leasing office, pool cabana, and restrooms. Rainwater cisterns and rooftop solar panels are visible in the background.
What were the most notable strategies used to earn LEED credits?
Rainwater harvesting and storage in expressive cisterns was a key sustainable strategy that earned LEED credits but also exemplified the actual practice. The cisterns are focal towers that redefine previously banal spaces. Each cistern collects 50% of adjacent roof area and stores upwards of 4,600 gallons of water for use in irrigating the new native landscaping. The cisterns also double as a detention device, ultimately helping to slow the flow of stormwater runoff on and off the site. This strategy was developed because of its duality as a design icon and its obvious functional success.
Listen to architect Chris Baribeau, AIA describe how the project team approached storm water management on the existing ECO Modern Flats site.
We decided to use solar hot water collectors here in Arkansas' sunny climate. At optimal performance, these are designed to provide an average of 75 to 80% of all hot water for the 96 apartment units. Not only are these systems extremely efficient and effective, but they are also calling cards accenting the flat roofline of the existing buildings, impromptu signage for the inner workings of a highly sustainable system.
Ultimately, a modern and desirable design aesthetic has created a sustainable community on this infill site. The many site-specific LEED credits available to a well-connected site root the project. Sustainability is inherently found in providing a project that is embraced by those who use it. Therefore, the most effective strategy was to encourage the desire for people to make a multi-family community on this site, not just through the executed LEED strategies but also by providing an aesthetic not attainable elsewhere. This is the power of good design to make a truly sustainable community and a relevant piece of architecture.
The central pool courtyard features prairie grasses and a low-mow lawn area and a grove of native sycamore trees. Pavement was removed to increase permeable surface and greenspace.
The original water use before the building was purchased was extremely inefficient; the previous owner had a sprinkler system running 24/7 in the summer months on the roof just to keep it cool. Early on we talked about a strategy for capturing rainwater and condensate from new roof mounted equipment. The buildings lent themselves nicely to rainwater harvesting with flat roofs and new insulation.
To best utilize that captured rainwater exterior landscape water is collected in two large cisterns and gravity-fed to a drip irrigation system. Drought-tolerant, native vegetation including prairie grasses and woodland species were selected to further reduce the need for water.
A simple steel culvert was upended to create a cistern. Rainwater harvested from rooftops is used to water the community garden and native plantings as they become established.
A bioswale planted with native sedges, rushes, prairie grasses, and wildflowers diverts and absorbs runoff from the parking area and provides an inviting entry from the west.
Closed-cell foam was used on the exterior walls to provide both a highly-effective air and vapor barrier while providing a significant increase in R-value.
Hot water heating was converted from a tank-type, gas-fired system to a hybrid hot water system with a rooftop-mounted solar thermal hot water heating array and supplemental gas-heated tank storage. Both of these strategies were chosen for maximum long-term savings in utility costs.
Aside from LEED certification, what do you consider key project successes?
From the operations side, I see the savings that our residents don't see. We see 50% reduction in water, gas, and electric bills, even after adding gas dryers in each unit. When I am on the property on a fall afternoon, I see half a dozen people using the pool patio; people who didn't know each other before are having meals together. We are creating a community of like-minded people, and that's not just a touchy-feely benefit, it's a financial one. Any advantage you can have with resident retention and word of mouth advertising is a good one. People want to live at ECO, and more importantly, people want to stay at ECO.
Careful engineering allowed installation of rooftop terraces. Reflective roof surfaces and insulation protect against the Arkansas sun, while solar panels provide 75% of hot water demand.
It's so rewarding to have to do so little advertising. Our leads come from word of mouth and web traffic, and we are at 100% occupancy with a one-year waiting list for apartments. We are setting the bar in design and strategic walkable location. Those advantages have boosted our rent rates beyond our projections. Of course, the design at ECO builds function into every square inch, so these apartments are more attractive and more livable than conventional units with a much larger footprint.
What one thing saved you or the project team the most time, money, or helped avoid an obstacle during the LEED process? What one thing cost you the most?
When we were in the planning stages, I sought out an energy efficiency consultant and found a LEED advisor-that's how this became a LEED project. Having the LEED roadmap in place from the very start, before design, really helped.
The biggest cost saver, both in terms of construction and operations, was the fact that we reused a concrete building. We furred out the walls and added insulation; added minimum four-inch insulation on the roof plus a white TPO roof; and installed new, efficient windows.
So we took a very solid building with great thermal mass and made improvements to the envelope, and the result is incredible savings in utilities-our monthly utility costs are half the pre-renovation costs.
Adaptive reuse was an important part of our strategy in selecting this site and while reusing an existing building was one of our biggest advantages, it was also the biggest challenge. The continued maintenance of the steel stairs, bridges, and beams that have been in place and exposed to the elements since the 70's has been a challenge and probably the biggest surprise. The building is virtually all concrete and steel, that's a big benefit, but in our climate those steel elements require frequent treatment, cleaning, painting. In some cases rust has made certain sections of stairs or stringers dangerous and we've had to selectively replace and/or repair components of the original structure.
Listen to owner Jeremy Hudson describe the benefits of adaptive building reuse at ECO Modern Flats.
About a year after the completion of the project we've replaced everything that required maintenance, but it will continue to be an ongoing requirement. You wouldn't have any of those problems building a new project on a previously undeveloped site, but the benefits of this renovation far outweighed those costs.
For other projects I would recommend two ways to minimize the risks of adaptive reuse, particularly for older buildings
- Assemble a strong design team.
- Thorough due diligence to uncover all surprises ahead of time.
Keeping in mind our mandate to make the buildings as energy-efficient as possible, the mechanical engineers identified, and the HERS raters collaborated on, an efficient HVAC system that provided increased efficiency and allowed for more design flexibility, all at a lower overall cost. The existing HVAC system was replaced with a ductless mini-split system. This system allowed for the removal of furred down areas to cover ductwork, reducing the cost associated with construction of the furrdowns and the ductwork itself. By using ductless systems, the mechanical engineer was able to select smaller "right-sized" equipment while maintaining increased efficiency of mini-split technology as compared to a PTAC or split system strategy. The smaller mini-split condensers were able to be placed on the roof to eliminate the aesthetic problem of through wall systems or large ground-mounted condensers, as well as the associated increased maintenance cost of ground-mounted equipment.
Improvements to insulation, installation of low-e windows, and a mini-split heating and air unit have increased comfort and reduced energy use.
What was the value of applying LEED to this project?
The testing and verification required in LEED was a real added value. When we started the blower door testing one of the buildings was not doing well. We figured out that one of the chase walls hadn't been sealed correctly. If we hadn't had that blower door testing that probably never would have been caught.
We're currently working on a joint venture project with a large out of state group who had experience with LEED. They expressed a desire for energy efficiency but questioned the administrative cost of LEED. I put my foot down and explained the benefits of the integrated design process that forces you to do things a little differently. A big piece of that learning process came through the third party testing. We're committed to continuing to build LEED certified building, not just because of the end result, but because of the value of the entire process.
We started out with the goal of being more energy efficient. LEED gave us a roadmap to do that. It is a huge marketing tool to be able to say that we are the first in the state and among very few LEED Platinum properties.
A modern, steel cable trellis supports a green screen of flowering purple hyacinth bean. This heirloom annual provides shade from summer sun and adds privacy for residents.
On this project the tenant does not bear the burden of the utility costs so there is not a split incentive for the owner that you might see on other projects. The owner has a financial interest in the efficiency of the building and every CFM (cubic feet per minute) of air leaking out that building is a cost to him. Often times the builder gets to leave the cost of inefficiency with the tenant but that's something that LEED protects. For Jeremy having LEED as an added layer of risk management and mitigation pays him back and helps his return on investment.
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