Rear extension and basement at 15 Woodside Road, Northwood

“As part of the development, a basement is proposed beneath the rear extension, extending partially beneath the existing dwelling and rear garden. A Basement Impact Assessment has been submitted in support of the application, together with supporting drainage information. The Council’s Flood Officer has reviewed the proposals and recommended additional mitigation measures, including the incorporation of a rainwater harvesting system.”

“The proposed basement room would be partially situated under the existing dwelling, proposed extension and partially under the existing patio area. In total, it would measure 7m in depth (approximately 1.6m in depth beyond the proposed extension ), 11m in width. The level of excavation would extend approximately 3.3m below ground level to allow for foundations and floor to ceiling height. The basement would provide an incidental room associated with the dwelling (cinema).”

“The application site consists of an existing two storey detached dwelling to the western side of Woodside Road, with a well landscaped rear garden and a large hard-surfaced front driveway.”

“The surrounding area is residential and consists of large, detached dwellings within generous plots of varying scale, design, and character. The property lies within Gatehill Farm Estate Area of Special Local Character. It is noted that there is mature landscaped garden situated to the rear of the site with several large protected trees of value including a category B tree. The site is situated within Flood Zone 1 and also within a Critical Drainage Area.”

“Concerns regarding the impact of the proposed basement excavation on the mature eucalyptus tree, including potential damage to its root system, effects on neighbouring land, and the contribution the tree makes to the character of the Area of Special Local Character. The Tree Officer has reviewed the Tree Survey and is satisfied that the works to create a basement would not cause any concerns to the long- term future of the protected tree.”

“Concerns that the submitted groundwater investigation is insufficient to fully understand the groundwater conditions at the site and the potential implications for neighbouring properties. An additional drainage plan and harvesting system was provided which has been further reviewed by the Flood Officer. The response recommended 2 conditions which would ensure that the basement would not lead to additional flood issues.”

“12444/APP/2026/747 RESOLVED: That the application be approved in accordance with the officer’s recommendation, subject to the agreed additional requirements and informative. 7.”