GMHA's purpose is to advance the factory-built housing industries through lobbying for reasonable non-discriminartory federal, state and local laws. Promoting the benefits of factory-built homeownersh GMHA's purpose is to advance the factory-built housing industries through Lobbying for reasonable non-discriminartory federal, state and local laws. Promoting the benefits of factory-built homeownership to consumers. Promote ethical and legal business transactions between customers and GMHA members through compliance of a Code of Ethics Development of studies, reports and other information pertinent to the growth and advancement of the factory-built housing industries.