DESIGN GUIDELINES FOR LIGHTWELLS ASSOCIATED WITH BASEMENT ROOMS

The creation of lightwells by the excavation of all or part of the front garden of a residential property will require planning permission. Where lightwells already exist, and are to be enlarged, planning permission will also be required for that enlargement.

Where there is no tradition of a lightwell in a particular property or street the introduction of such a feature can be harmful to the appearance of an area. For example, the scale of a property can be increased, or the softness given by a planted front garden can be lost with the consequent damage to the street scene, and the addition of further protective railings can add an unnecessarily cluttered appearance to the street scene.

In conservation areas such developments can gradually alter and thereby harm the character and appearance of that area.

Proposals for lightwells associated with the excavation at basement level have, until recent times, mostly been limited to specific and confined areas of the Borough. However, the demand for such excavations has now increased considerably with many proposals being considered to be inappropriate in their extent and design.

In order to help property owners to submit proposals which would receive planning permission, the Council has therefore produced this design guidance in order to clarify its policy and design approach to lightwells, as well as to give advice on the design of aspects of lightwells. The guidance also incorporates advice on Building Regulations requirements. Once adopted, following public consultation, this guidance will become Supplementary Planning Guidance to the Unitary Development Plan. The guidelines will also become a document that the Council will rely on in its determination of planning applications, and in connection with any appeal.

INTRODUCTION.

In London many of the larger Georgian terrace houses had separate front access to the basement to allow for coal, waste and service matters to be dealt with separately from the main entrance to the house. In smaller houses basement access would be to the coal cellars which were to be found under the pavements. However later medium sized and smaller London houses had no separate access and coal and bins were moved along the same corridors as everything else. Later in the 19th Century (after 1870) all medium sized and more and more smaller houses were built with a front garden (even those with basements). Gardens were regarded as adding status and, if kept in good order, improving privacy and the appearance of the house. Heavy iron railings (most removed during the Second World War) often enclosed the gardens. By the end of the century, the majority of houses had a front garden, or at least a forecourt, that is a paved stretch of ground of the depth of the bay window.

These front gardens now form the character of most of the Borough's streets and terraces, and when planted, provide a welcome greening of an otherwise hard urban environment.

POLICY FRAMEWORK

It is the Council's policy expressed in its Conservation Area Character Profiles (adopted as Supplementary Planning Guidance to the Unitary Development Plan) to discourage the excavation of front gardens in conservation areas. The policy states

"the excavation of front gardens to provide windows to basements to increase the light to basements should not be permitted in areas where the planting of the front gardens is an integral part of the design of the street or terrace and the extent of the excavation would negatively impact upon this. They may be acceptable if they are sensitively designed and proportioned."

Consequently, any application for a lightwell will be treated on its merits, taking into account local circumstances and the size of the excavated area. Where a significant number exist already in a particular street or terrace, such as the Studdridge Street Conservation Area, and where a different model has already become established, these may be considered acceptable. There will be instances where the construction of any lightwell would be detrimental to the character of a building or the street scene and would be refused permission. Examples of such cases would be, where front gardens or forecourts are particularly small and the creation of a lightwell would result in the loss of the entire garden, or where a large lightwell would be clearly visible from public areas. A proposal for a lightwell in a garden of any size where the whole garden were to be lost would normally be refused permission. In the case of a listed building whose special character would be harmed by the construction of lightwells, such a development would almost always be unacceptable. In some parts of some conservation areas, even the recommended forms of lightwells enclosed in this guidance may be harmful, for example where the front garden is clearly visible from the street, or where there is no front boundary enclosure.

The Council is also proposing to amend the Unitary Development Plan by adopting a new policy resisting the creation of basement flats, and the resultant lightwells, through either the conversion of existing basements or the creation of additional basements.

The policy specifies that planning permission would not normally be granted:

i. where such development would be out of character with the street scene, especially where this would result in the loss of a significant part of the front garden; or

ii) where such development would necessitate the creation of a lightwell at the rear or side of the building that would result in the loss more than 50% of the open area at the rear or side of the property as originally built; or, where the original property has already been extended or altered, the cumulative extensions and alterations would result in more than 50% of the open area being lost at the rear or side of the property as originally built;

ARCHAEOLOGY

There are parts of the Borough which are designated as Archaeological Priority areas. Were excavation is required in these areas the Council may need to take into account the policies in the Unitary Development Plan. If the property is located in an Archaeological Priority Area, applicants should first consult English heritage before embarking on any work.

MODEL DESIGN OF LIGHTWELLS ASSOCIATED WITH BASEMENT ROOMS.

Ideally, where a basement is being excavated to form additional living space, the lightwell should be formed in the rear garden. Such a location would almost always be more appropriate, unless it is a listed building where more stringent controls apply. There will be more scope at the rear for the provision of light and air to any new basement room, and there will be the opportunity to create links with any rear garden. Where a new front lightwell is acceptable in principle, it should be as discrete as possible, and allow the scale, character and appearance of the property, street or terrace to remain unchanged. The excavation should retain a significant amount of accessible and usable planting area at ground level. Fences or railings to surround the lightwell should be avoided, as they draw attention to the change, and would look cluttered especially if there are differing styles. The Council is not seeking to prevent the use of fences and railings on the front property boundary, or along the path leading to the front door.

Many houses in Hammersmith and Fulham have a splayed bay window on the front elevation (a result of the late Victorian love of fresh air and extra space); others have a square bay, while fewer have a flat elevation.

In the case of bay fronted houses, lightwells should not be larger than the narrowest part of the projecting splayed bay window. In the case of a flat fronted property or square bay, the excavation should be no wider than a maximum of 1250 mm. All excavations should not exceed 800mm from front to back. The Building Regs require that in order to prevent any one falling into a lightwell where it is deeper than 600mm, the opening should be protected by a guard. However, in order to avoid a cluttered appearance in the front of a property a horizontal grill should be used to achieve such protection over the excavation. Where the lightwell is used as a means of escape the grill must be capable of being opened by one hand as someone holds onto the ladder with the other. If the lightwell is not used as a means of escape, or required for ventilation, other traditional measures such as glass blocks could be used. Where a lightwell is used as a means of escape, a ladder as shown on the drawings will also need to be provided to affect the escape arrangements from the basement. (Guidance Notes incorporating Building Regs Technical requirements are found in Appendix 1) Any proposal should have sufficient space left in the front garden to provide the opportunity for planting, and in the case of small gardens, there should be at least sufficient space left for a sustainable hedge.

Recommended lightwells are shown in the drawings, these show a plan and section from front to back, for each type of property, together with dimensions. The examples have been designed to comply with building regulations requirements for means of escape in case of fire, if the only possible means of escape is through the front lightwell area.

APPENDIX 1: BUILDING REGULATIONS REQUIREMENTS

The following are regulations relating to Fire Safety and Means of Escape. There are two options available for achieving means of escape in case of fire.

Firstly, if the only means of escape in case of fire is by using the front lightwell area, then there are a number of rules which need to be met.

A lightwell with 800mm wide and 1250mm long (inside measurements) will be large enough to enable escape.

A non combustible ladder should be provided to allow anyone to step out of the lightwell to ground level. It should have a rake of 70 degrees and be positioned in such a way that 500mm of the window or door remains clear. A handhold should be provided above ground level.

Some form of protection is needed to prevent anyone from falling into the lightwell. If this protection is provided by the use of a horizontal grill it must be capable of being opened by one hand (as someone holds onto the ladder with the other). This could be done by providing spring loading or a counterbalance. Bars to the grill should be spaced at no greater than 100mm apart. The grill should be fitted only with simple fastenings clearly visible and readily openable without the use of a key.

Any new basement window should be at least 850mm by 500mm with an unobstructed opening.

In order to make the escape route safe from any fire breakout from any existing ground floor window , and that window is within 1.8m of the lightwell you will need to ensure that the ground floor window cill is at least 1100mm above ground level, or if the cill is lower than 1100mm above ground level then glazing to the windows to be made fire resisting and fixed shut. If the latter is not practicable you should install a smoke detector in the ground floor front room which contains, or is linked to, an alarm which will provide early warning to occupants in the basement.

Secondly, where the means of escape in case of fire is by using the internal staircase, the following rules need to be met.

All doors to habitable rooms (including the kitchen), entered from the entrance hall of the dwelling, should be fire resisting and self closing to ensure that a protected route is provided at this level, and the dwelling should be provided with a mains operated system of automatic fire detection. A detector should be provided in each habitable room (heat detector in the kitchen), also within the entrance hall within 3 metres of the door to each habitable room. Such a system should accord with the recommendations of BS 5839 Part 6.

Finally, for you should remember that it is the responsibility of owners, builders and their professional advisers to ensure that all temporary works are carried out in accordance with health and safety (construction) regulations and good building practice. Health and safety (construction) regulations are enforced by the health and safety executive.

Also, before you start any work you must obtain planning permission, building regulations approval, and any necessary highways consent where excavations are proposed adjacent to public highways (i.e. the edge of the pavement). In addition you should serve any necessary party wall notices and reach agreement with the adjoining owners where the proposed works affects the party wall. If this is not done before the work begins, the adjoining owners may take legal proceedings and halt work until such time the works affecting the party walls are agreed with them.

NB. All calculations and details relating to retaining walls and underpinning works etc. must comply with the Building Regulations to the satisfaction of the Building Control Officer.