The property owner who built the garage on the grounds of Siston Court will be ordered to rebuild key parts of the structure.
The historic Siston Court lies south-east from Emersons Green and was built in the 1500s.
A double-bay garage was recently built on the grounds next to the Grange, a Grade-II listed building, which has attracted complaints from locals and conservation officers.
While South Gloucestershire Council gave planning permission for a garage on the site, the consented plans were much smaller than what was actually built.
And crucially, the council set down strict rules on what materials could be used, to match the surrounding buildings.
Dominic Trotman-Dickenson, custodian of the south wing of Siston Court, said in a meeting: “I pass the Grange every day walking my dog, and have in-depth knowledge of the development. !My ancestors owned all of Siston for 220 years from 1650 to 1770, during which time they built the pepper-pot cottages known as the Lodge and the Gatehouse, as well as building the Grange.
“In 2009, South Gloucestershire Council designated Siston a conservation area with a view to preserving the integrity of this site, including the landscape and environment of the Grade-I and Grade-II listed buildings, and safeguarding it by strictly controlling any future developments.
“Unfortunately, the applicant took it upon himself to construct this garage in whatever manner he felt fit, with a total disregard for consented plans, and likewise ignored the conditions in the consented planning permission. At no point were external pillars ever consented to. The applicant built external pillars in an unauthorised and totally inappropriate stone.
“This is not a Blue Peter project where it can be botched to satisfy and appease the applicant. There are strict rules and guidelines on how it should have been constructed, and they have been blatantly flouted.”
The garage which was actually built included four concrete pillars on each corner, which must now be covered up.
That’s after the council’s development management committee voted on March 16 to approve retrospective permission for the garage, again with strict rules on materials.
The applicant Toby Nevitte said the pillars were needed to comply with building regulations, providing structural integrity.
