Appeal 3356600

The appeal is allowed and planning permission is granted for construction of a single storey extension to facilitate the conversion of the existing garage to an ancillary annex. The annex would comprise: [name], Open plan bedroom/living room at [site address] in accordance with the terms of the application, [name]/2024/2639, subject to the following conditions:

The development hereby permitted shall begin not later than 3 years from the date of this decision.

The development hereby permitted shall be carried out in accordance with the following approved plans: [name] TW7-A1 Rev 1 Existing and proposed floor plans, [name] TW7-A3 Rev 1 Existing, proposed south and east elevations, TW7-A0 Rev 1 Existing and proposed site block plans, TW7-A2 Rev 1 Existing and proposed roof plans, Location Plan.

The external materials of the development hereby permitted shall match those used in the existing building/dwelling.

The extended building hereby permitted shall not be occupied at any time other than for purposes ancillary to the residential use of the dwelling known as [site address] .

The National Planning Policy Framework (the Framework) was updated in December 2024, during the consideration of this appeal. Insofar as is directly relevant to the appeal, there are no substantive changes and no parties have been prejudiced as a result.

The main issue is whether or not the proposal, by virtue of its design, would constitute a separate unit of residential accommodation not ancillary to No [site address] and, if not ancillary, the possible implications arising for the character and appearance of the area and on the living conditions of the occupiers of neighbouring properties.

The appeal property is a two-storey semi-detached dwelling situated on a residential street. The property has a reasonably long rear garden with an existing garage and shed which runs along the majority of the rear boundary of the garden.

The proposal is for a small extension to the garage to facilitate its conversion into an ancillary annex. The annex would comprise a small shower room with WC and an open plan area which the plans indicate would be a bedroom/living room.

By virtue of the presence of a separate side access road and the facilities provided by the building the Council concluded that the development could not be regarded as ancillary to the host dwelling and would be perceived as a new residential planning unit. The Council refused the application on that basis.

The proposed building would undoubtedly display some design features not dissimilar to those which might possibly be expected with a new dwelling. However, the unit would be small; at around 22 sqm, the annex would be well below the [name] (NDSS) minimum of 37 sqm for a one-person independent unit. Moreover, the building would not benefit from any kitchen space or facilities which would allow meals to be prepared independently of the main dwelling. The open plan area would not include any partitions or separate bedroom space. In my view, the structure would be clearly subservient in terms of the scale of accommodation provided.

I consider that the proposed building would have a functional day to day relationship with the host dwelling. The proposal would clearly sit within the curtilage of [site address] and would be easily accessible by its occupiers. Further, the appellant has clearly stated that the building is not proposed for separate occupation and has suggested the use of a planning condition to expressly preclude any such eventuality. Indeed, this approach is set out within clause (d) of Policy SC7 of the London Borough of Hounslow Local Plan 2015 – 2030 (LP).

The proposed building would be situated within the rear garden area of the host dwelling and the side boundary would abut the access road onto which the existing garage door opens. However, the existing garage door would be removed and replaced by a window and as such, separate access would not be possible and those utilising the building would need to gain access through the main dwelling. I note the Council’s concern that these arrangements could change in future. However, the appellant has not applied for planning permission for a new dwelling and holds that the proposal would indeed be for an ancillary annex. As set out above, this use could be secured by a suitably worded planning condition which could reasonably be enforced. Any future proposal for the use of the proposed building as a separate residential unit would require the submission of a planning application which the Council could determine on its own merits. Therefore, even if different access arrangements were to occur in future the use of the building as an annex would, nevertheless, be secured through the aforementioned condition.

Based on the evidence before me, for the reasons outlined above, I conclude that the proposed building would not constitute a separate residential unit and would be an ancillary annex as applied for. [name] have concluded that the building would indeed be ancillary there is no evidence before me to indicate that the proposal would have an adverse impact on the character and appearance of the area or on the living conditions of the occupiers of neighbouring properties.

Accordingly, I consider that the proposal would accord with Policies CC1 and CC2 of the LP which, amongst other things, promote high quality design and seek to ensure that all new development conserves and takes opportunities to enhance the special qualities and heritage of the borough’s places. The proposal would also accord with LP Policy SC7 which states that the Council will support the extension and improvement of residential properties provided such works would maintain the character of the area and would not result in harm to the amenity of neighbouring residents, existing and future occupants, and the built and natural environment.

The National Planning Policy Framework makes clear that planning conditions should be kept to a minimum, and only used where they satisfy the following tests: necessary, relevant to planning, relevant to the development to be permitted, enforceable, precise and reasonable in all other respects.

Alongside the standard time limit condition, I have imposed a condition specifying the relevant plans as this provides certainty. In order to safeguard the character and appearance of the area I have included a condition requiring matching materials.

Additionally, in the interests of ensuring that the extended building is used only for purposes ancillary to the main dwelling, I have included a condition restricting the use of the building.

The appellant has suggested the use of a further condition to restrict permitted development rights and prohibit the installation of a door onto the access road. However, guidance is clear that permitted development rights should only be removed where absolutely necessary and, in my view, as I have included a condition requiring the use of the building to remain ancillary such a condition is not required to make the scheme acceptable.

For the reasons set out above, and having regard to all other matters raised, I allow the appeal.