Project name: 19 Father Francis
Location: Boston, Massachusetts, USA
Project type: Top floor apartment of a 7-story building
Date or time frame of construction: Skylights were installed and project was completed in Fall of 2019
Architect: Butz and Klug
Builder: John Benjamin, Benjamin Construction
High Quality Investments for Long-Term Futures
When the architects, Pamela Butz and Jeff Klug, first stepped foot on the roof of 19 Father Francis Gilday Street, a 7-story building in Boston’s South End, they were shocked by how much the building had deteriorated. The roof was 7" off-level and the masonry walls were without proper insulation. The evidence of degradation further justified the architect and developer's shared philosophy that investing in high performance products saves money in the long run.
High performance products are of particular interest to Butz and Klug given their clientele. In the last 23 years, more than half of their projects have been in Boston's historic South End, including three buildings on the same block as their office. In consideration of Boston's history, Jeff Klug "thinks of [Butz and Klug] as stewards of built history that is very rare in this country. The challenge is adapting that history to contemporary uses that will be practical for the next 150 years. There is so much history in the neighborhoods in Boston" and he sees honoring that history and high performance as complementary. “History and modernity can exist side-by-side and be wonderful,” Klug believes.
As Klug often explains to his clients, the major cost difference between renovating according to Passive House principles and renovating according to code expectations comes from the high performance daylighting (both windows and skylights). For 19 Father Francis, the notoriously frosty Boston winters made this investment an easy decision. According to Klug, the Lamilux PR-60 skylights made a “worthwhile investment from a comfort standpoint and a good investment in the long run.” When skylights are thermally continuous and airtight, they can drive down energy bills, enhance interior comfort, and prevent future renovations. Lamilux checks all of these boxes, supplying skylight solutions that offer industry leading performance, according to Passive House principles.
Impactful Structural Decisions
Utilizing best practice methods and solutions for high performance construction decreased the heating/cool demands of the apartment. As a result, the architects reduced the size of the ducts, which are typically concealed in the ceiling, and succeeded in adding 3" to the ceiling height. With proper insulation and heating system installed, the temperature never dropped below 65°F (18°C) during the first winter of occupancy following the renovation - even when exterior temperatures dipped to 7°F (-14°C).
From the beginning, the architect was interested in using cellulose or similar sustainable insulation in the walls and roof of this retrofit. To ensure durability and safety from moisture damage, and per the Historic Masonry Retrofit Smart Enclosure details, 475 New England Product Consultant Oliver Klein recommended INTELLO Plus at the interior studs for continuous air and vapor control throughout the walls and ceiling. Flat, unvented roofs can be a particular moisture risk, so 475 performed a WUFI analysis (for more on this, see our posts Unvented Flat Roofs: A Technical Discussion or Ten Golden Rules for Foam-Free Flat Roofs). The white roof created an additional challenge since the high albedo level slowed that inward drying. The strong vapor variable properties of Intello, together with its exceptional airtightness, ensures moisture levels stay within a safe range for the long term.
- Two Wall Assemblies:
- A framed Mansard Roof ranging from 7” depth at top to 42.5” at base
- Masonry wall framed with 2x6 studs
- Airtightness / Insulation:
- Blown-in cellulose throughout the envelope. INTELLO Plus used for airtightness at interior, seams taped with TESCON VANA and sealed with CONTEGA HF at the sub-floor.
- For all details, download both the Masonry Retrofit and Wood Retrofit Smart Enclosure guides.
The high performance envelope drastically reduced heating requirements and eliminated the need for radiant heat. In addition to the lower energy bill of the unit itself, the downstairs neighbor also received an unexpected gift: insulating the floor with 6” mineral wool for soundproofing delivered a lower energy bill for the downstairs neighbor as well!
One of the biggest challenges was the uninsulated, drafty elevator shaft, which opens directly into the apartment. They overcame this challenge by installing a high performance lift & slide pocket door inboard of the elevator doors
The unit also necessitated rooftop soundproofing since the building is located under the flightpath of Logan International Airport. This further reinforced the decision to choose Lamilux roof daylight solutions. Beyond the energy performance inherent to Lamilux skylight design, this choice helped the apartment to become "incredibly silent" despite air traffic overhead. The overall soundproofing is also due in part to Passive House levels of airtightness, confirmed by a blower door test score of 0.5 ACH50 - exemplary for this type of retrofit project.
Bringing Light to New Spaces
When designing with skylights, the quality of the light entering the space is very important to Klug. One way he creates the desired lighting effect is by installing skylights above deep shafts that splay outward, reflecting natural light deep into interior spaces. Klug mentioned he likes to add light where people normally look up, such as over the shower or the hallway.
In particular, the Lamilux skylights at 19 Father Francis were critical for rooms “trapped” at the interior with no windows. Klug wanted to make these “awful” spaces “wonderful.” The master bathroom is one such room that would have been “terrible if not for the skylight.” Per Klug's vision, the addition of a Lamilux FE to the space greatly improved the aesthetics, and by the end of the project, “everyone on the job had a picture on their cell phone of the sky over the shower” shared Klug.
Not only did Butz and Klug extend light into otherwise poorly lit spaces using two separate Lamilux FE skylights, they also installed a long and narrow Lamilux PR-60 skylight at the gallery wall. This custom skylight was delivered to the job site as a kit of parts that included triple layer insulated glazing units, thermally broken aluminum profiles (powder coated according to the client’s color preferences), and insulated flashing connections to the existing structure. It was hauled to the roof and then assembled and installed over the hallway to ensure seamless integration, including thermal continuity with the existing envelope.
The clients have an art collection on display in this hallway so the natural infusion of light from the Lamilux PR-60 created a museum-like aura, highlighting new dimensions of the artwork. In order to ensure a “perfectly level and straight” line between the plaster, the skylight installation required “massaging eighths of an inch” between the skylight profiles and the interior finish. This feat of precision required meticulous coordination between Lamilux and 475, as well as exceptional handiwork from Benjamin Construction.
- For skylight airtightness & insulation:
- INTELLO Plus wrapped into skylight opening, taped to jamb with TESCON Profil
- GUTEX wood fiberboard provides sustainable, foam-free thermal break
Klug experienced awe at the precision of the final product, especially since the system was designed and engineered in Germany, delivered as a kit of parts, and then assembled and installed on-site in Boston. He was especially impressed by the on-site representation during installation stating, “the [on-site representative] was amazing - just amazing”. These services - design of custom skylights via detailed shop drawings, and on-site representation during installation - are included in all PR-60 orders to ensure that each project is as successful.
Surrounded by Light
The clients moved into the building a week before COVID shuttered Boston businesses. The client is very satisfied with the interior comfort of their new space, especially during a time when they are unexpectedly spending more time indoors. “Any rooms trapped in the interior need daylight. Without the skylights it would be terrible,” said Klug.
FUN FACT: The design of the apartment was based on a Parisian apartment, characterized by wood paneling at the interior - they turned this design inside out, and instead of paneling the rooms, they paneled between the rooms so that things felt more object-like and open.