In May 1833, architect John Haviland created a new model for Cell block Seven, one with several advantages over earlier cell blocks at the site. The most noticeable difference between Cell block Seven and the previous two story cell blocks – Four, Five and Six – is the 30 foot barrel vault ceiling. In addition, Haviland set the catwalks back so they did not hang over the first floor. This made the block brighter and contributed to the cathedral-like atmosphere. When Cell block Seven was finished in 1836, it marked the completion of the original construction.