Circular Openings in Brickwork: How Bullseye Features Are Constructed
A bullseye window or porthole opening demands precise radial cutting and careful template work. Here is the method behind the feature.
Circular openings in brickwork appear in garden walls, gable ends, and boundary features across Kent. The one we built in a garden wall near Cranbrook involved cutting 64 bricks to individual angles using a diamond-blade wet saw, with each unit marked against a full-size plywood template before cutting.
Construction Method
The process starts with a template. We draw the full circle at actual size on a sheet of marine plywood, then mark the radial lines that define each brick position. For a 600mm diameter opening in a one-brick thick wall, you need roughly 32 bricks for the outer ring. Each brick is cut so the bed joint radiates from the centre point. The mortar joints on the outer face are wider than on the inner face; the skill is keeping this difference consistent so the ring looks even.
Structural Support
A decorative porthole in a garden wall carries minimal load, but a circular window in a gable end needs a precast concrete ring lintel or a fabricated steel frame to carry the brickwork above. The frame is built in, the brickwork is constructed around it, and the visible face is pointed to match the surrounding wall.
Where They Work Best
Bullseye openings are most effective in solid one-brick walls where both faces are visible. In a cavity wall, the construction becomes more complex because both leaves need to follow the curve independently, with flexible DPC and cavity closers around the opening.
For more on decorative brickwork patterns or front garden wall design, see our other guides. View our bricklaying services.