Cellar – A room under the ground floor of a building usually used for storage.
Basement – One or more habitable floors either completely or partially below ground
Retrofit Basement – The construction of a basement under an existing building where there is no existing basement although a cellar may already exist.


A new basement can be used for almost anything. It is important for us to have a full understanding of your intended basement use in order to give a full and accurate quotation.
The Fundamentals of any basement plan are:

  • Location of walls to form new rooms
  • Lighting requirements
  • Head height requirements
  • Choice of heating systems
  • Means of escape
  • Staircase location and design
  • Requirements for kitchen space, utility rooms, bathrooms, cinema rooms, swimming pools or any other special requirements



Excavation: To remove (soil, earth, etc.) by digging; dig out.
Underpinning: A solid foundation laid below ground level to support or strengthen a building
The key construction method used here is underpinning. In order to excavate the earth mass underneath a property the existing foundations must be supported and strengthened using the underpinning process. A series of “pins” are dug systematically under the property and filled with concrete. The property over this phase of the basement project will become completely supported by a new reinforced sub terrain structure. Steel joists will be incorporated to the basement construction to support any load baring walls, ground level floors or special features the new basement design may incorporate. Once the property is fully supported the earth mass may be excavated leaving a large open area beneath the property.


Tanking: The term often used to refer to the waterproofing of basements / cellars
Drainage: The natural or artificial removal of surface and sub-surface water from an area.
A polymer waterproofing system alongside a cavity drainage system offers the most modern and convenient way of keeping a new basement dry. Once the cavity drainage system is in place the sub floor may now be formed using reinforced concrete to form a sub floor or slab.
Any area below ground level is wrapped in polymer membrane – the walls and floor slab channel any ground water into the cavity drainage system below the floor where it is collected into a holding tank, which is automatically pumped up into the existing sewer


Fit Out: The design and completion of shell space (i.e. raw floor space bounded by walls) Including interior partitioning, floors, ceilings, electrical and plumbing requirements of its future occupants.
The exciting bit for anyone having a London Conversion Company Basement Conversion added to his or her home.
Your new basement space will be fitted out to your own individual requirements and specification.
Basement fit out utilises a range of tried and tested commercial application trades and processes
The sub floor is covered in with screed which is a system using sand and cement to leave a flat and level floor and may incorporate an under floor heating system.
Dry lining is used to form walls and ceilings and can also be used to create effects such as curved walls, bulkhead details and intricate ceiling designs.
Plumbing and electrical work is incorporated into the dry lining design before all walls are plastered to a finish.
This stage now moves into fine finishing with carpentry and joinery for doors, floors and decorative finishes as well as 2nd fix for bathrooms, kitchen and entertainment rooms and any other feature rooms
Decoration may be undertaken only once all these previous stages of fit out have met our own stringent standard of quality.
Upon final completion the client with be handed over the new basement with the following documentation where applicaple:

  • Electrical Sign Off Certificate
  • Gas Safety Certificate
  • Plans as Built Drawings
  • Drainage Layout
  • Technical Literature For Any Installed Equipment
  • Manufacturers Instructions For Appliances
  • Manufacturers Guarantees For Appliances
  • 10 Year Structural Guarantee

New Basement Conversions may include but not be limited to the following:

  • Basement Entertainment Room
  • Basement Guest House
  • Basement Nanny Quarters
  • Basement Playroom
  • Basement Swimming Pools
  • Basement Golf Simulator Rooms
  • Basement Gym
  • Basement Kitchens
  • Basement Wet Rooms
  • Basement Utility Rooms
  • Basement Cinema Room


When planning to retro fit a basement to a terraced or semi-detached house you will need to consider the Party Wall Act 1996. The Party Wall Act was introduced to enable owners living in close proximity to one another to develop their properties without causing unnecessary inconvenience to each other.