McGill created a Dutch gable with Classical pediment at the western end and, below this, added the semi-octagonal porch. He also replicated the north door in the bay immediately west. McGill added a near-identical pediment over the east gable and topped the pediments and buttresses with ball-topped obelisk finials. In 1722, McGill added the Palladian north porch to enclose the north doors; he also recast the curvilinear east gable, adding a Classical pediment to replicate the one at the west end.