The original site was built using Drupal as the content management system which, while sufficient to display a portfolio of previous projects, had some major shortcomings.
Firstly, every template I tried filled the underlying code of the pages it produced with extraneous xhtml tags. While these were necessary for the administrative control panels, I was keen that the code should be both semantic and totally accessible.
The second reason was the time and effort required to compare, select and then modify the modules already available for Drupal, when all I really wanted to do was to incorporate a Google map or a video from YouTube.
Finally, I wanted to re-design the structure of the site to improve navigability and make content easier to find for users and search engines. While at it, I also updated the design and edited much of the content.