• Did you know?
    • London is currently caught amidst the grip of a housing crisis.
    • More than 30% of homes in some parts of London have either converted or extended.
    • 7 out of 10 people surveyed prefer to extend their homes rather than to move.
    • 41% of people surveyed need an extra bedroom. Others need workshops, studios, etc.
    • Locations that have the lowest number of houses, yet highest property value are those that have seen the highest amount of conversions.
    • Westminster, Kensington, Chelsea and Camden have seen the most number of loft conversions.
  • Why do people convert their loft?
    • Extra living space
    • No planning permission
    • Saves outdoor space
    • Does not disrupt existing home life
    • Adds value to property
    • Insulates the home
    • No stress of shifting to another home
  • Do loft conversions add value to a house?
    • Yes!
      Loft conversion can add up to 20% to the value of your home.
  • What is the average cost of a loft conversion?
    • This depends highly on the area that you live in. But on average, a loft conversion will cost between £25,000 to £50,000
    • Ready-made loft conversions cost approximately £55,000
Conversion TypeCost (per square meter)
Room in the roof conversion (basic)£1,150 – £1,350
Dormer loft extension£1,250 – £1,450
Mansard extension£1,500 – £2,500
Hip-to-gable extension£1,500 – £2,500
Change of roof structure£1,350 – £1,550

*Please note, these values exclude professional fees such as architect, engineer, certificate of law, etc.

  • Things to keep in mind when converting a loft:
    • Planning:
      Loft conversions generally go as Permitted Development (PD). Permission will be needed if:

      • Property is listed
      • Property located in a conversation area
      • Property extends beyond PD area
    • Building

Building control surveyor will inspect loft conversion for the following requirements and issue completion certificate at the end:

  • structural integrity
  • construction quality
  • electrical compliance
  • mechanical compliance
  • Suitability
    • Roof Structure: Traditional frame is ideal as opposed to trussed roof for loft conversion.
    • Roof Pitch: Higher the angle of the pitch, higher the central head height.
    • Roof Height: Minimum 2.2m of usable space is required. If not available, raise the roof or lower the ceiling of below room.
  • Fire Safety
    Loft windows should be large enough and low enough to escape from. If not possible, a stair enclosure is required.
  • Staircase
    • Minimum height above pitch line = 2m
    • Maximum number of stairs in a straight line = 16
    • Maximum step rise = 220mm
  • Ceiling joints

The new ceiling joint spacers should have sufficient space to prevent new floor joist defection from touching below ceiling plaster.
New floor joists should offer at least 30 minutes of fire protection.

  • Loft insulation
    • Cold roof method: filling space between rafters with slab foam.
    • Warm roof method: use materials such as cover cap, tile battens and tiles over the rafters.

Author: Amol

Amol is an architectural designer and has worked on hundreds of residential projects in London since 2008.Having done his M.Arch from the Glasgow School of Arts he gained valuable experience in London working in the construction industry managing high-end residential projects, before founding Good Design and Build in 2015.You will meet him for initial consultation and work closely with him during all stages of your project