The London Conversion Company is a specialist basement conversion contractor offering additional services in connection to your basement conversion. Whether it is a simple single story extension or an extensive full house renovation and remodel The London Conversion Company offer a complete package solution for your individual requirements.

We will on occasion consider a full house refurbishment, extension/loft combination project without it being in relation to a basement project subject to our availability – Please enquire with our office staff for further details.

New Builds

With experience from the ground up we can ensure a smooth and quick build with the quality of work being to the highest of standards.


The London Conversion Company undertakes a variety of renovation projects, offering a service tailored to your design and needs, whether it’s a boutique design or a design sympathetic to the history of the property. The London Conversion Company undertake work complimenting all property styles and client needs from converting small – medium sized properties to larger scale modernization and redevelopment of London’s period properties.

Building works offered in coalition with a London basement conversion project

  •  Single story extensions
  • Double story extensions
  • Loft extensions
  • Remodeling

Planning and Design services

The London Conversion Company can assist with complete architectural design and structural engineering packages, offering the client peace of mind from the beginning. Once appointed we assist with:

Building Surveying

detailed survey for plans of the existing property.

Architectural Plans And Design

Design and plans for any alterations, new space such as basement conversions, loft conversions, property extensions and property renovations.

Building Regulation Plans

Working drawings for the approval of a building control and ultimately the project completion sign off and handover.

Structural Calculations

Structural calculations for building control approval and the onsite construction team where load-baring structures are to be used.

Planning Applications

We can offer assistance on your local district councils planning policy, Explain permitted development, what is covered and what is not and act on your behalf for submission of planning applications to your local district councils planning department.

All designs are versatile and tailored to your style and needs; allowing us to advise when needed on decisions to maximize the full potential that the property offers and highlight any key property features.

Basement Conversions

As the main focus of the company with 30 years experience in converting current cellars or from complete ground level down digging out, underpinning, structural waterproofing, construction of walls, to fit out we will supply a high quality of standard from start to finish, transforming your home and giving it a whole new lease of life.

A successful basement project should always get off on the right foot. Good quality accurate plans make planning applications simpler and will help any project run more smoothly. Easy to read plans help the onsite construction team through each phase of any build and as quality matters, it should be reflected in all stages including conception and design.

A Basement can offer anything you desire, from a new refined living space or kitchen to a luxurious wine cellar, cinema room or leisure space with a swimming pool.

As standard we will research any underground rivers or restrictions that may affect the development of your basement and offer solutions to any limiting factors.

The London conversion company has a bespoke team on force to offer services to fit out your design offering tailored decorative finishes and specialist carpentry always guaranteeing the highest quality available.

You can view previous basements projects at request as we are happy to arrange appointments for you to view our previous client’s homes.


As part of our specialist services we offer whole building structural alteration packages weather or not there is a basement involved.

As part of this package we can include but may not be limited to the following:

  • Site enablement
  • Making safe of electrics and gas
  • Strip out and disposal of interiors and existing non-load bearing structures
  • Making safe of unstable structures
  • Demolition and propping of load baring structures
  • Alterations to facilitate new layouts of buildings
  • Erection of steelwork and fitment of new lintels
  • Formation of new openings
  • Temporary propping

It is common under such a scenario to work closely with your own team onsite.


Trench fill foundations down to any depth, ordinary building contractors will generally not have the experience or the insurance to excavate foundations below 1.5m

  • New manhole formations
  • Drainage runs internal and external
  • Renewal of failed drains


Underpinning is the process of excavating usually by hand beneath an existing structure and strengthening the foundation.

A structure may require underpinning for the following reasons:

  • The original foundation has failed.
  • The usage of the structure has changed.
  • Subsidence has occurred.
  • Additional floors are to be added.
  • Close proximity construction that may affect the existing foundations.