Bryn Heulwen and Monmouth Montessori School

Bryn Heulwen and Monmouth Montessori School is a school with an integral master's house, constructed in an expressive domestic Gothic style. The building dates from the 19th century and is built of snecked rubble with red tiled roofs, red terracotta finials, and red brick chimneys. The design features a complex cruciform plan oriented along a west-northwest to east-southeast axis, with the master's house located at the southeast end, arranged in a shallow T-plan and backing onto the school building.

The north front has an asymmetrical two-and-a-half-storey composition, characterized by three separate and unequal gables, the outer ones being half-hipped. All gables have oversailing barge-boarded eaves and terracotta finials. The roof slopes down to a low level between the second and third gables, creating an entrance lobby. This lobby has a doorway to the left and two small square windows with small panes to the right. Above the lobby, a hipped dormer window with four lights and similar glazing is set into the roof slope. A wide gable to the left features a large transomed four-light window with a tile-hung tympanum and a chamfered segmental-headed surround, along with a triple-slotted stone ventilator in the apex. The gable at the right-hand end is set back, smaller, with a half-hipped roof and a transomed three-light window similar to those in the central gable. A small gabled wing, generally in the same style, is strongly set back beyond this. The half-hipped gable of the house at the left end is two-and-a-half-storeys high and has two altered ground-floor windows and a two-light casement above, echoing the school's window style. These windows are flanked by small wings with hipped roofs.

The southeast facade of the house has a central half-hipped gabled projection with coupled windows at ground floor, a three-light window at the first floor, and a side-wall chimney on the left. An open porch, with a stone plinth and arch-braced posts supporting a hipped roof, is situated in the angle at the base of this projection, leading to an inner doorway with a boarded door and a side window. A wide, diagonally-set rectangular bay window is located at the corner of the wing to the left. At the rear, the school has a half-hipped gabled wing connecting to the house. The roof of the main range slopes down to form an open verandah, originally comprising three bays, now reduced to two. The first bay has been enclosed, and a modern glazed lean-to has been added to the back of the gabled west wings, with two large skylights now fitted to the verandah roof.

Alterations to the school include the insertion of suspended ceilings, which now conceal all but the bottom of the original open roof trusses.