In 1804, Charles Heath recorded, "The interior has nothing worthy of attention and the only purpose to which it is employed is an occasional guardhouse, or powder room, for the military, when stationed at Monmouth."[18] The gatehouse had by this point been abandoned as a dwelling.[51] The lean-to extensions, including the guardhouse, were demolished around 1815.[52] In 1819, a pedestrian passageway was driven through the building on the upstream side[15] to help relieve the flow of traffic across the bridge. Before 1830, the gatehouse was owned by Monmouth Corporation, and subsequently the County Council, as inheritors of the medieval burgesses.[53] In a lengthy transaction, begun that year but not concluded until 1835,[54] ownership was formally transferred to the Duke of Beaufort as part of a property exchange.[23] The gatehouse roof was reconstructed in 1832, with deeper eaves and four decorative corbels on each side. A second passageway was added on the downstream side of the arch in 1845.[15] Since then, the structure has remained essentially unchanged, save for periodic maintenance and repair.[46]