Boathouse and deep-water dock, riverside landing stage, steps, balustrade and gates, Thames Eyot

This is a boathouse and deep-water dock dating from the 18th century, situated on a Thames Eyot. The boathouse and dock are constructed of stock brick and red brown brick with stone dressings. The design incorporates a rectangular, single-storey boathouse with a deep-water dock opening onto the river, intended for the storage and maintenance of private boats. It was intended to enclose views from a riverside terrace, with symmetrical flights of steps leading down to a landing stage, positioned asymmetrically on the river frontage.

The boathouse features an intact brick-vaulted jack-arched roof and a balustraded parapet, with a deep moulded cornice below. A circular window, or oculus, with a cast iron grille is present on the southern elevation. Blocked doorways are visible at the rear and on the north side. The round-arched opening to the river has a plain stone keystone and is flanked by brick piers with foliate stone capitals incorporating the head of a river god, although only the northern pier is now visible. Fixings remain for slatted timber gates that were previously in place. Remnants of timber stairs are built against the rear wall. Steel runners for pontoons are fixed to the lateral walls, although the pontoons themselves are no longer present. Formerly, a tiled roof-top terrace was recorded behind a balustrade adorned with urns matching those on the river frontage and the main house, but this is now inaccessible.

The stone balustrade is characterized by bulbous vase balusters set between square, panelled stone piers with a broad flat coping. Swagged urns embellished with fruits and lion's head masks punctuate the balustrade; the central urn features fruits and foliage issuing from the mouths of lion masks or river gods on either side. Much of this decoration is eroded. A double flight of stone steps, symmetrically arranged but offset on the river front, leads to a stone landing stage enclosed by ornate wrought iron gates. Mooring rings, each in the form of a bronze lion's head, are attached to the river wall flanking the stairs. The surrounding gardens were raised above the river to provide a view from a paved terrace walk. To the south, the balustrade turns west to connect with a loggia and grotto, which line the southern boundary wall, while to the north it terminates at the boathouse, sharing a similar architectural treatment.