How SIP Construction Helped Rebuild a 125-Year-Old Synagogue Without Losing Its History
Structural insulated panels (SIPs) are high-performance roof, wall, and floor building panels made of a rigid foam insulation core structurally bonded between two structural facings, used in place of conventional stick framing. They deliver a tighter building envelope, lower heating and cooling loads, and faster on-site assembly. At Temple Adas Israel in Sag Harbor, New York, they did something SIPs rarely get asked to do: help rebuild a 19th-century sanctuary from the inside out while keeping it looking exactly like itself.
Temple Adas Israel, originally known as Mischan Israel, is the oldest synagogue on Long Island. Services were first held in the building in 1898. By 2021, the congregation needed more than the original structure could give it: a basement level, real handicap accessibility, expanded classroom and community space, and a sanctuary big enough for a growing congregation. None of that could come at the cost of the building’s identity. The renovation had to add square footage without erasing 125 years of history.
Project Highlights
→ Renovation and expansion of an 1898 synagogue, the oldest on Long Island, with a two-year congregation displacement during construction
→ Three wall panel thicknesses (4 5/8″, 6 1/2″, 8 1/4″) and two roof panel thicknesses (8 1/4″, 10 1/4″), matched to different parts of the building
→ ACME jumbo panels precut at the factory, including circular and domed window openings
→ New basement and sub-basement housing classrooms, a library, and the building’s original mikvah, plus HVAC and electrical
→ Architect Bill Chaleff of Chaleff & Rogers, builder RLW4 Builders
→ Runner-Up Classic, Renovations category, 2026 SIPA Building Excellence Awards
The Project
The scope was not a simple addition. The original 1898 building actually sits beyond its own property line, with the historic entrance on Atlantic Avenue leading straight up a flight of steps into the sanctuary. The renovation, led by architect Bill Chaleff of Chaleff & Rogers Architects in Water Mill, added roughly 12 feet to the front of the building to expand the sanctuary, then recreated the original corner pillars and their triangular caps, which had been lost decades earlier. From the street, it still reads as the same building. Chaleff even used the siding pattern to preserve the visual impression of the old front staircase, though the real entrance moved to the side of the building.
That new entrance opens into a glass stairwell that connects the main level to a new basement below, with an elevator serving both levels for accessibility. The main level added a community room with a barrel-vaulted, coffered ceiling, its wood panels held in place by gravity and designed to be replaced with stained glass down the road. Sturdy folding panels separate the community room from the sanctuary, so the two spaces can open into one for larger gatherings. Below, the new basement holds three classrooms, a library, and the building’s original mikvah, the ritual bath once used by the congregation’s Orthodox women, preserved behind glass as part of the building’s history rather than removed. A tall sub-basement below that houses the HVAC plant and electrical controls the older building never had room for.
The project wasn’t simple to build, either. What began as a $6 million bid grew to $7.3 million as COVID-era shortages forced material substitutions across the two-year build. Construction started in 2021. The congregation, displaced to Sag Harbor’s First Presbyterian (Old Whalers’) Church for two years, returned home in a procession in May 2023, carrying each of the temple’s four Torahs, including one presented to the congregation by Theodore Roosevelt’s Rough Riders and another restored through the Memorial Scrolls Trust. The project reached full completion in 2025.
Why SIP Construction Mattered for This Renovation
The congregation itself set the direction: “Environmental stewardship is an important aspect of the Jewish faith, so they wanted a building that would be very energy efficient.” That, combined with a large, complex scope, made panelized construction the right fit for a building that needed to add a basement level, improve accessibility, update its interiors, and expand its footprint, all while keeping its original identity intact.
That kind of performance isn’t a design preference. It’s physics. A stick-framed wall has a stud every 16 or 24 inches, and every one of those studs is a thermal bridge, a path for heat to escape in winter and slip back in come summer. A SIP wall replaces that whole assembly with a single, continuous layer of rigid foam insulation bonded between two structural facings. No studs breaking the insulation. No gaps at the seams for air to leak through. The result is a building envelope that holds its temperature instead of constantly fighting to recover it, which means the HVAC system works less, the electric bill runs lower, and the space inside stays steadier, warmer in January, cooler in July, without a furnace or air handler running overtime to keep up. On a building built in the 1890s, long before anyone engineered for airtightness at all, that’s not an incremental upgrade. It’s a different building envelope entirely.
That performance is also where the environmental benefit actually lives. Heating and cooling is what burns most of a building’s operating energy year after year, and that energy carries a carbon cost, whether it comes off the electric grid or out of a furnace. A continuously insulated, low-leakage SIP envelope needs meaningfully less of that energy to hold the same temperature a stick-framed wall would need far more energy to hold. Less energy burned means less carbon produced to keep the sanctuary warm on a February morning or cool during an August service, every single year the building stands. For a congregation that told its architect this mattered as a matter of faith and not a talking point, that reduction is exactly the kind of concrete, measurable outcome the building itself now delivers, year after year it’s in use.
The building’s design also created a real engineering puzzle: three different wall thicknesses and two different roof thicknesses, each suited to a different part of the structure.
Wall panels: 4 5/8″ (3 3/4″ EPS core, R16), 6 1/2″ (5 5/8″ EPS core, R24), 8 1/4″ (7 3/8″ EPS core, R32)
Roof panels: 8 1/4″ (7 3/8″ EPS core, R32), 10 1/4″ (9 3/8″ EPS core, R40)
Three key benefits stood out on this project:
Installation speed: ACME’s jumbo roof and wall panels cut down the number of individual panels installed, which cuts down the number of seams, which cuts down the time and complexity of getting the building closed in.
Energy efficiency: SIPs gave the addition an extremely well insulated, tight envelope, reducing the load on the HVAC system and the building’s electricity use. That’s a real upgrade over a structure built in the late 1800s, long before anyone was thinking about a building envelope at all.
Precut precision: The panels arrived from ACME’s factory already cut to spec, including the intricate circular and domed window openings the design called for. Cutting those shapes on site, in a historic building under a tight schedule, would have cost real time. This project didn’t have to spend it.
Using three wall thicknesses and two roof thicknesses across one building would have been a genuinely complicated job with stick framing and field-installed insulation, matching different framing depths and insulation types by hand, room by room. SIPs simplified it: each thickness and R-value was built into the panel at the factory, so the variation was handled before the panels ever reached the job site.
Between the tighter envelope, the faster installation, and the precut precision, SIPs gave this project the modern building performance the congregation asked for, without disturbing the historic character it was just as determined to keep. That’s a building that asks less of the land it has stood on since 1898, and less of the congregation that will keep heating, cooling, and maintaining it, for however many generations gather there next.
Recognition
2026 SIPA Building Excellence Awards Runner-Up Classic, Renovations category. The Structural Insulated Panel Association recognized the project for design and structural engineering innovation, creative use of SIP construction, and environmental sustainability, judged against projects across the country.
Project Details
| Location | Sag Harbor, NY |
| Building | Temple Adas Israel, built 1898, oldest synagogue on Long Island |
| Architect | Chaleff & Rogers, Water Mill, NY (Bill Chaleff) |
| Builder | RLW4 Builders LLC, Southampton, NY (Roy "Buddy" Wines IV) |
| SIP Supplier | ACME Panel |
| Construction | Began 2021; congregation returned May 2023; project completed 2025 |
| Total Project Cost | $7.3 million |
| SIP Walls | 4 5/8" R16, 6 1/2" R24, and 8 1/4" R32 EPS core panels |
| SIP Roof | 8 1/4" R32 and 10 1/4" R40 EPS core panels |
| Recognition | Runner-Up Classic, Renovations, 2026 SIPA Building Excellence Awards |
Renovating a building people care about?
Historic buildings, additions, and architecturally sensitive renovations all bring their own constraints. We will tell you plainly whether SIPs are a fit for yours before you commit to anything.
Frequently Asked Questions
Can SIPs be used to renovate a historic building?
Yes. Structural insulated panels can be manufactured to match the exact dimensions, openings, and detailing a historic renovation requires, including custom shapes like the circular and domed window openings used in the Temple Adas Israel project. Because panels are precut at the factory, complex historic details can be built into the panel before it ever reaches the site, which reduces the on-site fabrication work that historic renovations usually require.
Can a single project use SIPs of different thicknesses?
Yes. Different parts of a building often call for different wall or roof thicknesses depending on structural loads, energy targets, or how a space is used. The Temple Adas Israel project used three wall panel thicknesses (4 5/8″, 6 1/2″, and 8 1/4″) and two roof thicknesses (8 1/4″ and 10 1/4″) across a single building, each manufactured to the R-value the application needed.
Do SIPs work for additions to older buildings?
SIPs are well suited to additions on older structures because the panels arrive from the factory ready to install, which limits the time a historic building’s original structure is exposed during construction. They also let a project add modern energy performance, a tighter envelope with less thermal bridging, without changing the original building’s exterior appearance.
What is a mikvah, and how did the renovation address it?
A mikvah is a ritual bath used in Jewish practice for spiritual purification. Temple Adas Israel’s original mikvah, no longer in active use by the congregation’s Reform practice, was preserved in a glass enclosure in the building’s new basement level as part of the renovation, keeping it visible as part of the synagogue’s history rather than removing it.
Want to Learn More About SIPs?
If this project raised questions about how SIPs work on a renovation or addition, these resources are worth reading next.
→ SIP Building Basics: A plain-language overview of how SIP construction works and how it compares to conventional framing.
→ When to Use SIPs: Not every project is the right fit for SIP construction. This page walks through the building types, budgets, and timelines where SIPs perform best.
→ Sustainability & Carbon Savings: How a tighter, better-insulated envelope translates into lower carbon over the life of a building.
Sources for this profile:
Anne Surchin, “A Complicated Task: The Renovation and Addition to Temple Adas Israel,” 27east.com
Stephen J. Kotz, “Temple Adas Israel in Sag Harbor Nears End of $7.3 Million Renovation Project,” 27east.com
Stephen J. Kotz, “Sag Harbor’s Temple Adas Israel Celebrates Its Return Home,” 27east.com
The 22-foot roof panels are the detail worth lingering on. SIP roof panels carry structural load across their whole span, not just at the points where a truss would bear weight. That structural capacity is what let Taylor Hollow eliminate trusses and open up a vaulted ceiling that would otherwise have required a redesigned framing plan and a bigger labor bill.
This was not a luxury development where buyers could absorb high utility costs as a footnote to their mortgage. The affordable units serve families at 50 to 60 percent of area median income. Performance had to be real, and it had to be measurable. For a family already stretching every paycheck, a heating bill that spikes in January is not an inconvenience. It is a choice between staying warm and paying for something else that mattered that month.
SIP buildings perform this way because the building envelope has no thermal bridging and virtually no air infiltration. Every stud in a stick-frame wall is a thermal break, a path for heat to escape in winter and slip in during summer. A SIP wall eliminates that path entirely. The result is a home that is quieter, steadier, and cheaper to run for its entire life: a bedroom that stays warm on a cold night without the furnace working overtime to keep up.