David co-founded and has led the nonprofit Development Center for Appropriate Technology (DCAT) since 1992. DCAT launched their program Building Sustainability into the Codes in 1995 to create a sustainable context for building codes. David’s wide-ranging building experience — from troubleshooting construction of the high-tech cover of Biosphere2 to conventional concrete, steel, masonry and wood, to adobe, rammed earth, and straw bale — has grounded DCAT's work in more sustainable building and in codes and standards. David served two terms on the U.S. Green Building Council (USGBC) Board of Directors, founded and chaired the USGBC Code Committee for ten years, served on the initial drafting committee for the International Code Council's International (ICC) Green Construction Code (IgCC), and was Vice Chair of an ASTM subcommittee on sustainability where he led the task group that developed the first ASTM Standard Guide for Design of Earthen Wall Building Systems. DCAT and David received ICC's 2007 Affiliate of the Year Award and a 2007 USGBC national leadership award. Current work includes helping lead the Safer Insulation Solution coalition to address toxic flame retardants in plastic foam insulation through changes in building codes. Other recent and ongoing work includes direct involvement with EPA's Tribal Green Building Code Work Group, developing the framework and much of the content for the EPA's Tribal Green Building Codes Development Guidance website, and helping develop a new EPA Tribal Green Building and Codes Toolkit. David also helped develop and gain approval for the new Strawbale Construction Appendix in the 2015 International Residential Code (IRC) and contributed to the IRC Code Commentary for that appendix. David is also a founding faculty member of the Emerge Leadership Project.