“The proposed works comprise the excavation of a basement beneath the footprint of the existing dwellinghouse. The proposed depth of the basement is approximately 2.85m, with the width (side to side of the house) a maximum of 4.5m and length (front to back of house) a maximum of 7.5m. A single internal staircase is proposed to link the existing ground floor with the proposed basement. To clarify, the proposed basement does not include any lightwells or associated works which would allow natural light to this space.”
“6.24 The proposals [are] for a new basement under the footprint of the house with a depth of 2.8m from ground floor to top of basement slab. The basement footprint would be c33sqm. No lightwells are proposed. The basement works will, by necessity, involve temporary engineering works associated with protecting the structural stability of the house and neighbouring building. However it is considered that these works would be entirely part of the basement works to [the house], and they do not constitute 'a separate activity of substance that is not ancillary to the activity that benefits from permitted development rights.'”
“A basement dug beneath an existing building within a terrace is one of the riskiest situations in which to construct a basement. Because the property shares its existing foundations with its neighbours and also because it provides lateral support to its neighbours, any movement of the existing house resulting from the works will directly impact on its neighbours.”
“(2) The following operations or uses of land shall not be taken for the purposes of this Act to involve development of the land (a) the carrying out for the maintenance, improvement or other alteration of any building of works which – (i) affect only the interior of the building, or (ii) do not materially affect the external appearance of the building, and are not works for making good war damage or works begun after5th December 1968 for the alteration of a building by providing additional space in it underground.” (i) affect only the interior of the building, or (ii) do not materially affect the external appearance of the building, and are not works for making good war damage or works begun after5th December 1968 for the alteration of a building by providing additional space in it underground.”
“The enlargement, improvement or other alteration of a dwellinghouse by carrying out below the dwellinghouse or its curtilage of basement or lightwell development integral to and associated with basement development, being development comprised within Class A, Part 1 of Schedule 2 to the Order and not being development comprised within any other Class.”
“Permitted Development A. The enlargement, improvement or other alteration of a dwellinghouse. Development not permitted A.1 Development is not permitted by Class A if – (a)… (b) as a result of the works, the total area of ground covered by buildings within the cartilage of the dwellinghouse (other than the original dwellinghouse) would exceed 50% of the total area of the curtilage (excluding the ground area of the original dwellinghouse); (c) the height of the part of the dwellinghouse enlarged, improved or altered would exceed the height of the highest part of the roof of the existing dwellinghouse; (d) the height of the eaves of the part of the dwellinghouse enlarged, improved or altered would exceed the height of the eaves of the existing dwellinghouse; (e) the enlarged part of the dwellinghouse would extend beyond a wall which – (i) forms the principal elevation of the original dwellinghouse; or (ii) fronts a highway and forms a side elevation of the original dwellinghouse; (f) subject to paragraph (g), the enlarged part of the dwellinghouse would have a single storey and – (i) extend beyond the rear wall of the original dwellinghouse by more than 4 metres in the case of a detached dwellinghouse, or 3 metres in the case of any other dwellinghouse, or (ii) exceed 4 metres in height; (g)… (h) the enlarged part of the dwellinghouse would have more than a single storey and – (i) extend beyond the rear wall of the original dwellinghouse by more than 3 metres, or (ii) be within 7 metres of any boundary of the curtilage of the dwellinghouse opposite the rear wall of the dwellinghouse; … (i) the enlarged part of the dwellinghouse would be within 2 metres of the boundary of the curtilage of the dwellinghouse, and the height of the eaves of the enlarged part would exceed 3 metres; (j) the enlarged part of the dwellinghouse would extend beyond a wall forming a side elevation of the original dwellinghouse, and would – (i) exceed 4 metres in height, (ii) have more than a single storey, or (iii) have a width greater than half the width of the original dwellinghouse; or (k) it would consist of or include – (i) the construction or provision of a verandah, balcony or raised platform, (ii) the installation, alteration or replacement of a microwave antenna, (iii) the installation, alteration or replacement of a chimney, flue or soil and vent pipe, or (iv) an alteration to any part of the roof of the dwellinghouse. … Conditions A.3 Development is permitted by Class A subject to the following conditions … (c) where the enlarged part of the dwellinghouse has more than a single storey, the roof pitch of the enlarged part must, so far as practicable, be the same as the roof pitch of the original dwellinghouse.”
“Permitted development A. The carrying out on agricultural land comprised in an agricultural unit of 5 hectares or more in area of – (a) works for the erection, extension or alteration of a building; or (b) any excavation or engineering operations, which are reasonably necessary for the purposes of agriculture within that unit. Development not permitted A.1 Development is not permitted by Class A if – … (c) it would consist of, or include, the erection, extension or alteration of a dwelling…” (a) works for the erection, extension or alteration of a building; or (b) any excavation or engineering operations, which are reasonably necessary for the purposes of agriculture within that unit. A.1 Development is not permitted by Class A if – (c) it would consist of, or include, the erection, extension or alteration of a dwelling…”
“I accept the premise of that submission but reject the conclusion. The planning legislation is not impressed by the indivisibility of single processes. It cares only for their effects. A single process may for planning purposes amount to two activities. Whether it does so or not is a question of fact and degree. If it involves two activities, each of substance, so that one is not merely ancillary to the other, then both require permission. Applying that test to the facts of this case, I am left in no doubt that the construction of the reservoir will involve two activities, each of substance. The extraction of so much gravel will not merely be ancillary to the carrying out of the engineering operations, as it would usually be, for example, where foundations were dug for a bridge or a building…”
“It is a question of fact and degree in each case. Looking at the facts of this case, which involves the removal of so large a quantity of minerals, the only possible conclusion is that the development would consist of a mining operation followed by an engineering operation.”
“In the present case the Secretary of State had not determined what was incidental to the provision of a hard surface, but went straight to the purpose and the indivisibility of the operation. He had substantial regard to purpose. For example he referred to the “sole purpose of the excavations” and went on to find that “the removal of the necessary quantity of earth to achieve that aim took place as an integral part of the operation …”
“Converting an existing residential cellar or basement into a living space is in most cases unlikely to require planning permission as long as it is not a separate unit or unless the usage is significantly changed or a light well is added, which alters the external appearance of the property. Excavating to create a new basement which involves major works, a new separate unit of accommodation and/or alters the external appearance of the house, such as adding a light well, is likely to require planning permission.”
“1.13 All additions to dwellinghouses, apart from very minor changes and purely internal alternations, are classed as ‘development’. However, not all ‘developments’ require express planning permission, because many smaller additions to dwellinghouses are granted a “deemed” consent by the GPDO provided they comply with specific criteria relating to their size and position. This creates a situation whereby larger or more prominent additions to dwellinghouses are fully tested through the planning application process to discover whether adverse impacts occur; whilst smaller developments are deemed to be acceptable provided specific tolerances are complied with.”
“7.2 Basement extensions are an increasingly popular method of extending houses, particularly in urban areas characterised by terraced houses where other forms of extension may not be possible. The excavation of basements is a form of development, but the GPDO is silent as to whether there are circumstances in which basements can be viewed as ‘permitted development’. Notwithstanding this silence, the volume limitations imposed by Class A of Part 1 are capable of being interpreted to include basement extensions, and anecdotal evidence suggests that many local authorities do this. A small minority of design guides published by local authorities contain guidance on designing basement extensions, suggesting that a set of tolerances to guide basement extensions could be designed.”
“[T]he overwhelming majority of local authorities (see questionnaire results below) interpret Part 1 of the GPDO to include underground extensions. Basement lightwells, on the other hand, being classed as an engineering operation rather than the enlargement of a dwellinghouse, do not benefit from ‘permitted development’ rights.”
“Where it is considered that a smaller basement development falls within the specific limitations set out in the Order an application for planning permission is not required.”