London Basement Conversions: Five Tips for Technical Design
1. Tanking
2. Natural Lighting
3. Acoustic Design
4. Artificial Lighting
5. External Materials
1. London Basement Conversions and Tanking
Tanking refers to the application of a waterproof membrane to the walls and floors of a basement structure. Various companies manufacture the membrane and it is typically a dense studded plastic sheet. At Shape Architecture we use systems created by RIW or Delta Membranes in our basement conversions. Of prime importance is a full understanding of the way in which each product is installed and typical details provided by each company. For many of our basement conversions in Fulham or Kensington we have had meetings on site with the technical design managers from the tanking company and our basement contractor to ensure every detail is understood.
2. London Basement Conversions and Natural Lighting
Our most successful London basement conversions have been those that used natural lighting to the best effect, both to provide light into the interior and to lead you through the various spaces to the source of light and the corresponding views out. We have in a number of basement conversions in Fulham for example, located large format rooflights over the ground to basement stairs and so brought light down into the space through the stair void, with views of the sky visible as you go up the stairs. Other basement conversions in London have used large sliding doors giving onto the garden lightwell which ensures the room located in this part of the basement, typically the family or play room, is filled with natural light. Lightwells are always successful in bringing light into the basement and these can be located at the garden and street side and also set in the middle of the ground floor, which works very well in bringing daylight into the heart of the basement. Structural glass panels set within the ground floor also bring daylight into the basement in areas where lightwells might not be considered. We have in a recent basement conversion in Kensington located a series of glass panels in the ground floor in a tight rhythm, above which is a large rooflight and this will provide further daylight and in an interesting pattern into the basement conversion. It is the combination of a variety of sources of natural light, in a number of locations at various sizes that help ensure a basement conversion is filled with light.
3. London Basement Conversions and Acoustic Design
Acoustic separation is best achieved in the design and location of various rooms, such that noise sensitive spaces are located away from those that are likely to generate noise. This should be an important consideration in the design and layout of the basement conversion and the floor plan above. The next sequence of decisions relate to the technical design of floors, walls and doors to achieve good levels of sound insulation. The floor will have a sound absorption layer by companies such as Regupol and this helps address the structural borne passage of sound though footfall for example. The build-up of the ground floor and basement ceiling detail will also have a further layer of acoustic insulation set above the plasterboard ceiling. The ceiling itself can be an acoustic plasterboard.
4. London Basement Conversions and Artificial Lighting
Artificial lighting in basement conversions can much enhance the quality of the interior. We have found with our basement conversions in Fulham and in Kensington that a good approach is the combination of simple and elegant task lighting, with feature light fittings and the lighting of architectural features such as stairs and glass bridges. In one of our basement conversions in London, the feature stair brings natural light down into the basement through the void it sits in and at night is itself lit up to emphasize the simple and elegant geometry of the stair. Various other basement conversions have used lights set at the edges of glass panels and set within the well of a rooflight. In the same way that natural light can lead you through a space, so can artificial light, and this often works well with lighting set in the garden spaces.
5. London Basement Conversions and External Materials
In respect of basement conversions the palette of materials typically relates to how the various lightwells are treated. The garden lightwell is typically the largest space and very often has a glass bridge or platform set over it. The dripping and splashing of rainwater is a key concern as unsightly staining may occur and the detailing of materials should take this into consideration. For example when render is used it should stop at least 150mm above ground level on a stainless steel drip, with the exposed 150mm being in engineering brickwork or with a treatment applied to the face of the concrete wall behind. We have also used ceramic tiling as a wall finish to a number of garden lightwells and this can work well given the robust nature of the material and the potential for colour and patterns. We have very often used paving as the floor finish to the lightwell floor and this works well. There is also a very wide range of paving or tile types that can be selected. Our basement conversion in Fulham at Ellerby Street incorporates an elegant glass and timber stair linked to the glass bridge over and this forms the key feature in both design and materials of the lightwell.