• Design-Build-Develop

    As architects, we are interested in achieving the highest level of design.  As builders, we are interested in letting the process of making further enhance the architecture.  As developers we work to maximize the opportunities of each site.  In all aspects we employ strategies that function in multiple levels, to have the greatest impact.  Work with Onion Flats to realize your projects full potential. 


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    Onion Flats new 25 unit Passive House project’s foundation is in and the BuildSMART Passive House Wall Panels are being installed.  These prefabricated wall panels have the Passive house windows and exterior rigid insulation pre-installed, simplifying and speeding up construction of the Passive house envelope. 

    more about this project

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    "Be sure to check in for updates."

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  • under construction

    1. 3RD & GEORGE HOMES - Northern Liberties

    2. BICYCLE STABLES - Fishtown

    3. COLUMBIA HOMES - Fishtown

    4. SHACK 6 - Fishtown  

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    The PHFA Project began in 2014 when Tim McDonald and 25 other stakeholders, under the auspices of the Architectural Research Center, a think tank within Temple University Architecture program, approached the Pennsylvania Housing Finance Agency and asked them to initiate a project which would have ALL affordable housing in Pennsylvania be designed and constructed to a Net-Zero-Energy-Capable standard by 2030. The “tool” proposed to achieve this was Passive House.  McDonald’s design/build firm, Onion Flats, had already built Belfield Townhouses, Pennsylvania’s first Passive House Certified project, serving formerly homeless families and demonstrated as a proof of concept that Passive House projects can be built on affordable housing budgets.  

    2016 DVGBC Groundbreaker Awards

    Read more about the PHFA Project

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    "This PHFA Initiative to date has funded almost 900 new Passive House affordable housing units in PA"

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  • Onion Flats IN THE NEWS

    Despite winnowing energy consumption by up to 80 percent, passive design is often seen as an added—and untenable—first cost to building developers. Now, one market sector is getting a boost to make the investment more palatable: affordable housing. Thanks to a movement that originated in Pennsylvania, many states are now offering tax credits and incentives to encourage the construction of buildings that are in compliance with the Passive House performance standard developed by the German-based Passivhaus Institut and adapted to the United States market by the Passive House Institute US.

    "read the full article"

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    Since its completion in 2013, Belfield Townhomes has won numerous awards and has generated new opportunities for net-zero capable affordable housing.  Most recently PHFA has been awarded the 2016 DVGBC Groundbreaker Award for its "Passive Project" co-created by Onion Flats Partner Tim McDonald.

    Read about all the awards here

    Belfield Tomehomes Project Page




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    "Belfield Townhomes challenge the standards of subsidized housing."

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