MANSARD RECAST
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2022 | Somerville, Massachusetts
4,200 SF | 2 Bedrooms | 2 ½ Bathrooms
All Electric Net PositiveMansard Recast is a new single-family residence completed in 2022 and designed to meet Passive House, LEED Platinum, and net-positive performance standards, though formal certifications were not pursued. Designed by Garth Goldstein, the project prioritizes measurable performance outcomes, long-term durability, and all-electric operation over designation.
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The Historic Commission required a traditionally proportioned mansard roof. Rather than limiting the performance strategy, this requirement shaped it. The street façade maintains a historically appropriate presence, with natural slate roofing, carefully scaled dormers, and proportions consistent with the surrounding neighborhood. The form reads as contextual and restrained.
Behind this familiar profile, the roof geometry shifts. A sawtooth plane is integrated above and behind the mansard, oriented due south to support a large photovoltaic array. This configuration allows for substantial solar production without altering the historic street-facing silhouette. The solar system is embedded within the architecture rather than expressed as an applied element.
The composition blends influences without relying on replication. A cantilevered carport introduces a horizontal counterpoint to the vertical mass of the mansard, creating a controlled balance between historic reference and contemporary interpretation. The project aligns nineteenth-century form with present-day performance requirements through deliberate integration rather than contrast.
Construction occurred under tight urban conditions. The house was built in close proximity to neighboring foundations along a narrow one-way street, complicating crane access and prefab staging. Modular construction was further challenged by the mansard geometry, dormers, and integrated sawtooth roof planes. Despite these constraints, the prefabrication strategy reduced the overall construction schedule by approximately two months.
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The home operates fully electric and was constructed using non-foam wall and roof assemblies. The enclosure was detailed to achieve ultra-low blower door airtightness, supporting high levels of energy efficiency and indoor air quality. The photovoltaic array enables net-positive energy performance under modeled conditions.
Material selections reinforce durability and environmental responsibility. The exterior combines natural slate with sustainably harvested Red Grandis cladding and recycled teak. These materials support longevity while maintaining compatibility with the historic context.
The interior contrasts the traditional exterior expression with a restrained contemporary palette. Artisanal concrete, white oak millwork, unpainted plaster, and wax-finished Venetian plaster create a modern, tactile environment defined by material clarity rather than ornament.
Mansard Recast demonstrates that historically appropriate architecture and advanced building performance can be aligned through integrated design and construction. The project adapts a conventional mansard form to accommodate high-efficiency, all-electric operation and substantial on-site solar generation without altering its contextual presence.
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Working with Group Design Build was fantastic. Their expertise with systems worked out quite well. Our drawings where very exacting and they were executed perfectly.
Garth Goldstein
