Basement Architects in London
Shape Architecture has built a reputation as experienced basement architects in London. Our experience spans all types of basement design from double basements in Kensington, to numerous basement conversions in Fulham alongside whole house refurbishments, as well as basement extensions in Kensington constructed below mews houses. On this basis of this knowledge we are able to set out what we believe are the ingredients for a successful basement project. These range from the principle issues of light and space, to points relating to the design and construction process of a basement, and the many issues of detail that arise in these projects thereafter.
A Guide to London Basement Extensions
Shape Architecture has recently produced a brochure detailing ten basement conversions in London that we have designed and built over the last three years and this is available for download on our website www.shapearchitecture.co.uk . The brochure details a wide range of basements from single storey to double storey, those located in conservation areas to Mews locations and in Cul-de-Sacs. This breadth of experience enables us to suggest those issues that we have found to be important in designing successful basement extensions in London which we list below.
Basement Extensions: Key Design Issues
Five tips in designing a basement extension:
1. Internal Height
2. Location of the Stair
3. Type and Number of Lightwells
4. Artificial Lighting
Tip 01 – London Basement Conversions: Internal Height
The floor to ceiling height of a basement extension is an important decision. Our basement conversions in London vary from 2.75 metres to 3.5 metres. We would say that 2.75 metres should be considered as a minimum height, whilst a figure around 2.9 metres will feel spacious. The feeling of space in a basement project cannot be gauged simply by a floor to ceiling calculation however; a significant factor will also be the number, size, and location of rooflights and other sources of natural light. The proportions and size of each room and the way in which rooms are accessed all play a part as well, alongside colour schemes and the use of artificial lighting. Floor to ceiling height is a good starting point though.
In respect of the technical issues relating to basement extensions in London, one should also be mindful of the level of the water table. This is a technical consideration and can be simply addressed. A soil survey should always be undertaken at the planning stage to a depth of the desired internal height plus the lowest part of the excavation required to form the foundations. Most planning applications will require this analysis as part of the Construction Methodology Statement that forms part of the planning application.
We have designed a number of basement extensions in London where the basement sits below the water table. The approach to the structural design remains largely the same. As noted above the key is to have a full understanding of the ground conditions at the design stage in order that an appropriate design is pursued.
Tip 02 – London Basement Conversion: Location of Stair
The location of the internal stair connecting the existing ground or lower ground floor is very important. Not only is this the means by which the basement extension is accessed, it is also very often a design feature in itself as well as being a means by which natural light can be brought down into the basement. We have explored a number of different locations for stirs in our portfolio of basement extensions in London. For example in one of our Fulham basement conversions we have located a stair in a large void within an open plan kitchen dining space. Located over the void is a large rooflight and this provides a great deal of light into the heart of the basement and views of the sky from the basement. In another Fulham basement we have located the stair in a glass cube located at the garden edge in order that the basement stair and its enclosure interact with the garden and provide again a great deal of daylight into the basement alongside views of the garden. Other London basements that we have designed and built have stairs that follow the exiting run of stair flights. In various Kensington Mews basements we have also integrated stairs in lightwells.
Tip 03 – London Basement Conversions: Type and Number of Lightwells
Lightwells can provide light, air, views out, an exit out, and an amenity space. Clearly, they are an invaluable part of every basement conversion and can define the character of the basement. At Shape Architecture we have also designed basements without lightwells that introduce other means for light to enter the basement. We will describe that method later.
Common to many London basement extensions is the garden lightwell. Typically at the basement level a series of sliding doors or bi-fold doors give onto the lightwell. At ground floor level the lightwell is then crossed by a link from the ground floor that provides access to the garden beyond. The type of sliding/folding door is an important choice and this relates to the width of the glazing frame. Narrower frames can be much more expensive than a ‘standard’ 50mm with.
Our basement conversions in London have explored the connection between the interior and the garden beyond the lightwell in a number of ways. These vary from glass bridges with glass balustrades to more significant glass platforms incorporating patterns of clear and semi opaque finishes to the glass. Often at the far ends of the glass platform a steel grille is incorporated for ventilation to the lightwell below. We have also linked an elegant timber and glass stair to a glass bridge in a basement conversion in Fulham. At other basements in London a series of steps lead from the lightwell up to the garden. These steps provide easy access to the garden, as well as an elegant feature when a glass balustrade is applied at garden level.
Tip 04 – London Basement Conversions: Artificial Lighting
A basement extension will benefit greatly from the addition of simple and elegant artificial lighting. Many of our basement conversions in London have featured lighting set around the internal stair, in the garden lightwell, and around feature rooms such as the wine store to great effect. Successful lighting schemes marry efficient lighting with several elements of feature lighting such as an elegant pendant fitting, with the lighting of several architectural features such as the internal stair or a glass bridge. It is also often successful when natural light sources such as rooflights have discreet artificial lighting set into the well of the rooflight.
Tip 05 – London Basement Conversions: Storage
Basement extensions offer a great opportunity to add additional storage to a property. These solutions can range from large storage rooms built under the garden or terrace, to various stores located off the basement circulation space. In several of our London basement conversions we have built storage rooms giving off the lightwell built under the garden which have been constructed as one large room or two rooms with separate access doors. The basement corridor linking the garden to street side accommodation provides an excellent location for various store rooms.
A Guide to London Basement Extensions: Further Issues
London Basement Conversions: Fire Safety
As basement specialists in London, Shape Architecture is experienced in designing basements that comply with fire regulations. A typical issue is the desire for a contemporary open plan series of spaces, with stairs that are located in reception rooms. In both cases these design features move away from the traditional fire rated layout of a hall with stair, and then a series of cellular rooms set off the hall. An increasingly common solution is the use of domestic sprinkler or misting systems. In our Fulham basement conversions we have often located a water storage unit for the sprinklers system in basement store rooms. Alternatively an upgrade to the water supply pipe entering the property can provide the required water supply.