The architectural profession, specifically over the past century, has generated the belief that the art and act of building, is merely the means by which Architecture presents itself to the world. Our work is focused on reestablishing those familial bonds, opening up lines of communication between them, embracing the risk inherent between them rather than limiting it and contributing to a culture of thinking which strengthens the discipline of architecture from within.

Onion Flats Architecture formerly known as PLUMBOB LLC, is a licensed architectural firm in PA, NJ, NY, DE, MD, and VA.  Onion Flats Architecture specializes in sustainable design and building practices and has produced multiple LEED & Passive House Certified projects.  Our experience in our own design/build/development projects provides our clients with innovative & cost effective solutions.



Onion Flats has been practicing in Philadelphia as developers, architects and builders since 1997.  Our work has been published widely and has won national and international awards, focusing on innovated solutions for highly sustainable urban communities, including some of the first LEED & Passive House Certified projects in the region.  Our mission is to integrate seamlessly the process by which our ideas about architecture, the city, and sustainable development go from interpretation to construction to habitation.  We choose to explore and experiment with the entire spectrum of intelligent and practical approaches to the way in which buildings manage their own resources, and create communities that sustain themselves.



Onion Flats Construction, formerly known as JIG Inc., is the licensed construction/ construction management division of our development/design/build collective.

Historically the jig has been understood by the craftsman as an intermediary construction one fabricates for the sole purpose of aiding or supporting the construction of an equally purposeful object. In fact, the functional purpose of a jig for any craftsman is such that it operates most distinctly at the level of a translation device between the raw material and tool through which it is transformed. 

Onion Flats Construction serves as the jig to securely and accurately hold and manage our projects throughout the building process, and to ensure a successful transformation from design to reality.


G.R.A.S.S. (Green Roofs And Solar Systems) is leading the way to a greener and healthier region.  As designers and installers of vegetative roofing systems since 2006, GRASS took on an early role in collaborating with the Philadelphia Water Department in forwarding Philadelphia’s storm water regulations and legislation.  We have become one of the region's leading green roof contractors and have installed more than half a million square feet of green roof / storm-water systems, and urban roof-top landscapes.

Working with G.R.A.S.S. early on in the development process is the most efficient and cost effective way to incorporate vegetative roofing systems into your projects.  Our sister company, Onion Flats Construction has been recognized internationally as an industry leader in green building techniques and possesses an intimate understanding of the coordination necessary to successfully incorporate these systems in the overall building detailing process which benefits our clients early in their development cycle.