21 And 23, Asmuns Hill

21 and 23 Asmuns Hill are a pair of artisans' cottages built in 1909 by architects Barry Parker and Raymond Unwin. The cottages feature painted pebbledash with a distinct weathered appearance above a brick plinth in Flemish bond, and they have tile kneelers. The roofs are tiled with swept eaves and exposed rafter ends, and the gable ends showcase exposed purlins.

The design follows a paired, canted bay style, which is common throughout the artisans' quarter of Hampstead Garden Suburb, with slight variations. These cottages are two storeys high and have a symmetrical two-window arrangement. Each has gable-facing half dormers on the first floor, with four-light casements that span the entire width of the dormer and include a weathering strip.

There is a flat-roofed dormer on the party wall that extends across both units, a feature also present on Nos. 27 and 29 Asmuns Hill. Unlike Nos. 9 and 11 Asmuns Hill, these cottages have an axial stack on each return and another on the front roof slope, with rear stacks aligned with the front dormers. The left-hand stack has been lowered. All openings are flat arched, with entrances set in shallow recesses that have canted sides, one of which extends to form the side of a deep canted bay. The roofs of each bay extend over the entrances to create a porch area that spans the party wall and is supported by a plain upright. The doors of No. 21 retain their original design, and all casements are also original.

The Asmuns Hill group is a significant example of a complete streetscape designed by Parker and Unwin.