Party Walls

Walking the aisle of your favorite home improvement store, you’ll notice the wide array of options for very efficient light fixtures. Don’t be fooled – truly efficient lighting design is achieved through thoughtful layout and proper controls.

A high performance building warrants an efficient lighting strategy. With so many efficient LED fixtures available on the market, individual fixture efficiency is rarely an issue. However, these fixtures are often placed in high concentrations or at a higher wattage than necessary to adequately illuminate a space. The result is high lighting power density (LPD), which is measured by dividing the total light fixture wattage in a room by the square footage of that room. Even with controls such as occupancy or vacancy sensors, high LPDs are especially energy intensive in frequently occupied common areas, e.g., corridors and lobbies of multifamily buildings, impacting the bottom line efficiency of all buildings.

Projects pursuing Passive House certification are impacted by an optimized lighting scheme more so than a code-built building. As the heating and cooling energy used in a Passive House building decreases due to an excellent thermal envelope, the ratio of lighting energy used increases. Reducing lighting energy use can drastically improve the building’s overall primary energy demand. (more…)

It is safe to say we are in a climate crisis. Of the last 17 years, 16 have been the hottest on record.[1] Sea level is expected to rise by as much as eight feet by the end of the century.[2] And by 2050, as many as 140 million people will have been displaced by climate change.[3] The time to act is now, and a major area of impact is buildings, which account for 40% of carbon emissions in the United States. Better envelopes, lighting, and mechanical systems are helping buildings become more efficient, which means an increasing proportion of carbon—up to 68% of a building’s lifetime emissions—is locked up in materials.[4] This “embodied” carbon gets released during a material’s extraction, manufacture, transport, maintenance, and, eventually, disposal.

If our industry is to meet the 2030 Challenge of carbon neutrality by the close of the decade, we will need to reevaluate building materials and select low-carbon alternatives.

Figure 1: Courtesy of Faithful+Gould

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As mentioned in Foundation Waterproofing 101, water damage to a foundation can be very costly and difficult to repair. By paying close attention to how and where water might enter the foundation during the early stages of construction, typical failures can be avoided by following these simple guidelines…

For the Designer: Keys to proper installation

Design and Quality Assurance

• Don’t wait to design the foundation waterproofing system after you’re already in the ground!
• Specify and detail the appropriate system for each project. Meet with manufacturer reps early!
• Require shop drawings and kickoff meetings to ensure the entire team understands the importance of the design! Review examples of common failures.
• Get your consultants on board early: Geotechnical engineer, Structural engineer, Waterproofing/enclosure consultant.
• Review warranties, require third party inspections, installer certification, and contractor training.

For the Installer: Keys to proper installation

Substrate preparation

• Provide smooth continuous surfaces to install waterproofing – minimize jogs, protrusions, and sharp edges.
• At slabs: compacted fill/rigid insulation board/rat slabs
• At walls: fill bugholes, remove/grind concrete fins, mortar snots, fill form tie holes, verify form release agents and compatibility.

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Designing buildings with water protection in mind is critical to protecting buildings from future damage, difficult/costly repairs, and potential litigation. Foundations are by necessity in the ground. So is water. Foundation waterproofing is intended to keep them separate, by providing a layer of protection between a below-grade structure and the moisture present in the surrounding soil and fill. Waterproofing is especially important when the foundation lies below the water table or in a flood zone. Read on to learn about different approaches and materials used to waterproof foundation walls and slabs and specific detailing needed to provide a watertight enclosure. And, check out Part 2 of this series for specific guidance and examples to achieve a watertight enclosure.

Why is foundation waterproofing necessary?

Foundations are basically holes in the ground that want to fill with water. Poor site drainage, through-wall penetrations, concrete cracking/mortar joints and movement, door/window/vent openings, flooding, high water tables, hydrostatic pressure – all contribute to the propensity for water to fill the subterranean void we have established. Foundation leaks are difficult and costly to rectify, not to mention designer/contractor financial liability. Water in a basement is water in a building. Excess moisture within a building is a recipe for higher RH and increases the potential for condensation, and mold and other allergens.

Luckily, foundation water intrusion is usually preventable. The goal is to identify all the potential water transport mechanisms, and address them, through good design practices, proper detailing, and quality execution. (more…)

On April 21, 2018, two blocks of ice weighing exactly one ton each were placed into what appeared to be identical sheds in Times Square. The purpose? To measure how much each block would melt over a 30-day period, ultimately demonstrating the efficacy of Passive House construction methods.

The first shed, or Ice Box, was built to meet current NYC Building Code standards, which lack stringent requirements for building envelope performance. The second was constructed using building principles adopted from the Passive House Standard, including the utilization of high performance building materials, a superior airtight building envelope with advanced insulation, and triple-pane windows.

After 30 days of exposure, the Ice Boxes were publicly unveiled, and the results were exactly what building professionals had anticipated. The block of ice contained in the Ice Box constructed to NYC Building Code resulted in a final weight of 126 pounds, while the block of ice within the Passive House Ice Box weighed an astonishing 756 pounds, retaining 42% of its mass!

So, What Did We Learn… (more…)

If there was ever a silver bullet when it comes to best practices in multifamily buildings, air sealing would be it. Compartmentalization – or air sealing each unit to prevent infiltration between units and to the exterior – addresses many major issues we see in buildings.

Better HEALTH

• Air sealing is the best strategy to keep pests out and limit their movement within a building.
• Air carries a lot of moisture, so eliminating air leaks helps keep buildings dry and reduces the risks of mold and water damage.
• Compartmentalization prevents contaminated air from garages, basements, attics, and other undesirable sources from entering living spaces.

Improves COMFORT

• Air sealing reduces drafts and eliminates hot and cold spots.
• Limiting air transfer from one unit to the next reduces transmission of noise, smoke, and odor between units.

Wastes less ENERGY

• Air sealing lowers heating and cooling bills maintaining a more consistent indoor temperature.
• Compartmentalization improves the performance of ventilation and mechanical systems by limiting pathways for stack effect – the force of warm air from low to high – to occur in larger buildings.

How to Air Seal Multifamily Units

It’s important to remember to create a complete air barrier around the entire cube of a multifamily unit, not just to the exterior – any and all penetrations need to be sealed.

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On May 1^st, 2018, Steven Winter, founder and chairman of Steven Winter Associates (SWA), and Harold Bravo, Accessibility Consulting Director at SWA, moderated an event at the Hafele Showroom to discuss senior housing in New York City and its relation to accessible and sustainable design. The event was organized jointly by the AIANY Design for Aging Committee (DFA) and the AIANY Committee on the Environment (COTE).

A panel of experts presented perspectives from architecture, real estate development, and municipal government, and discussed the challenges of designing sustainable, comfortable, accessible, and healthy buildings for the aging population in New York City. The panel included Kleo J. King (Deputy and General Counsel, Mayor’s Office for People with Disabilities), Isaac Henderson (Development Director, L+M Development Partners), Jack Esterson (Design Partner, Think! Architecture+Design), and Rich Rosen, AIA, LEED AP (Principal, Perkins Eastman).

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The pattern along the water’s edge in Bridgeport, Connecticut presents a familiar scene to New Englanders: active harbors and historic homes interspersed with blighted buildings and weathered infrastructure. The city’s architecture suggests a prosperous past and a difficult present. But this city—prone to acute and chronic flooding, and facing the ills of climate change and sea level rise—will not leave its future to chance. The City of Bridgeport has a plan to survive and even thrive in the next decades of environmental change, and may position itself as a national leader in resiliency.

In this context, “resiliency” refers to adaptation to the wide range of regional and localized impacts that are expected with a warming planet. Last fall, David Kooris, former Connecticut Director of Housing, visited SWA’s Norwalk office and presented Bridgeport’s vision: Resilient Bridgeport. The project began in 2014 when the City assembled a multidisciplinary design team, led by New Orleans-based Waggonner and Ball, to prepare an integrated resilience framework for the U.S. Department of Housing and Urban Development’s (HUD) Rebuild by Design Competition. The following year, Connecticut was awarded a HUD grant of $10,000,000 to develop a plan for reducing flood risk, improving resilience for the South End and Black Rock Harbor areas, and building an ambitious pilot project in the South End that combines physical barriers and low impact development.

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*click here to read Part 1 of this blog

In climates with significant heating and/or cooling seasons, Passive House projects must have a balanced heat or energy recovery ventilation system. These systems use a heat exchanger to transfer heat and moisture between the outgoing return and incoming outdoor airstreams. The operation of recovery ventilators reduces the energy required to heat and cool decreasing the building’s carbon footprint. Project teams can select either:

• Heat Recovery Ventilators (HRV) that transfer heat from the return air stream to the outside air stream; or,
• Energy Recovery Ventilators (ERV) that transfer heat and moisture from the return air stream to the outside air stream.

Deciding between an HRV and an ERV gets more complex when the Passive House concept is scaled from a single-family home to a multifamily program. What the industry has learned from the development of airtight buildings and programs such as Passive House and R2000, is that indoor relative humidity must be controlled through continuous ventilation. The extremely air tight building envelope required of a Passive House, combined with high internal moisture gains from an occupant dense multifamily program (coming from occupants, kitchens and bathrooms), forces additional moisture management considerations during mechanical ventilation design. Maintaining acceptable interior relative humidity in both the heating and cooling season is paramount for building durability and occupant comfort. It’s appropriate that Passive House professionals claim this simple motto: “Build tight, ventilate right!”

In New York City where the multifamily Passive House market is rapidly growing, there is a significant heating season and a demanding cooling season with high humidity (Climate Zone 4A). With this seasonal variation, there are four primary operating scenarios for an HRV or ERV that need to be considered during design:

Summer Condition – HRV

An HRV operating in the summer (hot-humid exterior air and cool-dry interior air) introduces additional moisture to the building through ventilation. Heat is transferred from the incoming outside airstream to the return airstream leaving the building which cools supply air, but exterior moisture is not removed from the incoming air. The building’s dehumidification load increases as a consequence of additional moisture from the outdoor air.*CON*

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It has been clear for some time that energy codes are on course to require carbon-free buildings by 2030. Adoption at the local level will see some areas of the country getting there even sooner. For example, California has set net zero goals for its residential code by 2020. These developments have accelerated the debate about the effectiveness of energy modeling versus performance-based approaches to compliance.

Let’s start with energy modeling, where change is coming for the better. In the past, the energy modeling community has been required to continuously respond to energy code cycle updates with new baseline models. That is, the bar for uncovering savings would be increased each and every time a new energy code was adopted. Following a code update, program staff and the energy modeling community would have to go through another learning curve to determine where to set a new bar and how to model the changes. (more…)