The Thunder House and Attached Garden Wall Running Approximately 15 Metres South to Munstead Orchard and Approximately 135 Metres to South East to Quadrangle

The Thunder House and attached garden wall were built in 1895 by Edwin Lutyens for Gertrude Jekyll. The garden house is made of Bargate rubblestone with brick dressings and features a plain tile roof. It has a triangular plan and is 1-2 storeys high, with a curving stone stair leading up to a viewing level on the south front. The left side has archways at ground level, while the other sides have openings that are now weatherboarded on the west. The eaves are coved below an oversailing hipped roof, and the north angle of the building is flanked by angled buttresses.

The attached garden wall has projecting rounded coping and runs approximately 15 metres south to Munstead Orchard and about 135 metres southeast to Quadrangle. The wall is approximately 3 metres high along Heath Lane, ramping down from the Thunder House and up again to terminate at Quadrangle, which was formerly Miss Jekyll's potting sheds and is now a house. There is a round-arched doorway with a studded board door next to the Thunder House, as well as a rear entrance to Munstead Orchard and other inserted entrances next to Quadrangle. The Thunder House was originally located at the end of Miss Jekyll's garden and was used by her to observe thunder. The garden is listed as Grade I in the Register of Parks and Gardens of Special Historic Interest in England.