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Whether you need assistance with planning your vision or true build out numbers, our affiliate architecture and design companies are at your service.  With in-house expertise, we are able to provide finely honed visual awareness and a strong understanding of various building materials and structures.


It Starts with a Vision is more than a motto; at HDA, it’s the philosophy we live by.

In 1986, Jack Holleran, president of HDA, envisioned a professional service firm providing creative and timeless design with exceptional customer service. Since then, we have designed over 100 million square feet nationwide, totaling more than $3 billion in construction costs and completed over 250 projects in more than 44 states.

Over our 36 plus year-old history, our team has provided architecture, interiors and master planning services across varied market segments to include office, beverage wholesaler, interiors, industrial / distribution, power retail centers, auto dealerships, multi-family, mixed-use, hospitality, and craft brewery market sectors.

Entrusting a project to our Architect-Led Design & Build Team limits the time and effort required of the client. It allows busy owners to focus on their core activities and rest easy knowing the project is being handled in the most professional, efficient manner possible. Our Design-Led approach applies innovative solutions and tighter controls over all aspects of the project, from preservation of the design to a close adherence to budget and construction schedule.
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With 27 years of unparalleled experience spanning local, regional and national markets, O’Toole Design Associates is ranked one of the largest interior design firms in the St. Louis area. Working by the philosophy “we make space work” and placing the needs of their clients at the forefront, O’Toole Design Associates has positioned itself to be an industry leader in creating unique, functional and productive environments for corporations, small businesses, educational facilities, hospitality, medical offices and retail establishments. The company’s expansive local, national and international list of clients include World Wide Technology, World Wide Technology Asynchrony Labs, Ascension Health, The JCC Staenberg Family Complex, The Magic House, Bunge, Solae, Clayco, PayneCrest Electric, Cequel III, Baltimore Ravens and Atlanta Falcons Training Facilities, Cutler-Hammer/Eaton in Pittsburgh.
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