A Georgian Conservatory for a Grade II Listed Presbytery

This conservatory was designed as a dining extension to a Grade II listed presbytery in a quaint Hertfordshire village, opening off a kitchen that had been dark and enclosed, and framing views of the mature gardens and the church beneath which the house nestles.

The challenge with a listed building of this austerity is adding a substantial glass structure without disturbing its classical proportions. The answer was a lean-to form matched to the scale of the existing building, with a central hipped gable projecting forward to give the composition a formal focal point and a canopy over the dining table. The gable carries custom-milled Gothic curved glazing bars that overlap to form true arches, each holding individual panes rather than any applied grid, a nod to late Georgian Gothic detailing. Side windows and French doors repeat the multi-pane pattern of the sash windows on the house itself.

Everything is sapele hardwood, chosen for its tight interlocking grain and stability, which matters when curved roof bars and slim glazing bars have to hold their line through seasonal movement. It is hand-finished in a multi-coat microporous white. Window furniture is cast iron monkey-tail handles with matching peg stays, the doors use a period-style rim lock, and the ogee cast aluminium gutters and downpipes read as cast iron without the weight or the rust.

Two technical problems shaped the build. Conservation officers required slim profiles, which we met with heritage double glazing using gas fills that hit modern insulation values inside a thin traditional rebate. And the presbytery's old lime-mortar stone walls absorb moisture, so a stepped lead flashing system was cut into the horizontal mortar joints to isolate the new roof from water running down the facade. Opening the kitchen wall required a goalpost steel frame carrying the floors above.

Twelve weeks from consent to handover, and roughly seventy percent more daylight reaching the back of the kitchen.