01 / 15 Construction & conversions
A loft conversion is usually the most cost-effective way to add a bedroom, a home office or a bedroom with an en-suite to a London house without moving. We survey your loft, recommend the type of conversion that suits your roof and your plans, and then build it from the first steel beam to the last coat of paint.
Because our team also includes electricians, plumbers, tilers and decorators, your loft is finished by the same company that built it. There are no separate trades for you to find and no gaps between them.
Is it right for you
Most London lofts can be converted in some form. At the survey we check four things.
Check 01
The height from the top of the ceiling joists to the underside of the ridge decides how much usable space you get. As a rule of thumb, around 2.2 metres or more makes a conversion straightforward. Lower lofts can often still work with a dormer, a mansard or by lowering the ceiling below.
Check 02
Older houses usually have a traditional cut roof with rafters and purlins, which is simpler to open up. Many homes built from the 1960s onwards have W-shaped trussed roofs, which need new steel beams designed by a structural engineer before the loft can be used.
Check 03
A new staircase has to fit on the floor below and meet building regulations for headroom, usually above the existing stairs. We plan its position early, because it affects the layout of both floors.
Check 04
Water tanks, chimney stacks, boiler flues and wiring may need moving. We include this in the plan and the quote, rather than finding it halfway through.
Types
Roof windows are fitted into the existing roof slope, so the shape of the roof stays the same. It is usually the simplest, quickest and lowest-cost option, and often suits lofts that already have good head height.
See our Velux loft conversion page
A box-shaped extension is built out from the rear roof slope, creating full standing height across much of the loft. It is the most popular type in London because it adds a lot of usable space for a reasonable cost.
See our dormer loft conversion page
On semi-detached and end-of-terrace houses with a sloping side roof, the side is built up into a vertical gable wall. This makes the loft much larger and gives room for the new staircase, and it is often combined with a rear dormer.
See our hip-to-gable loft conversion page
The rear roof slope is rebuilt at a very steep angle with a flat top, giving the most usable space of any loft type. Mansards usually need planning permission and are common on London terraces and in conservation areas where a box dormer would not be allowed.
See our mansard loft conversion pageTwo dormers are joined in an L shape, one on the main roof and one over the rear outrigger. It is well suited to Victorian and Edwardian terraces and can add two rooms, such as a bedroom and a separate bathroom.
See our L-shaped loft conversion pageFor newer homes with W-shaped roof trusses, the trusses are replaced by steel beams and new joists designed by a structural engineer, so the loft can be opened up. Most trussed roofs can be converted once the structure is redesigned.
See our trussed roof loft conversion pageWe carry out the structural and weathertight work, including the dormer, steels, floor, windows and staircase opening, and you finish the interior yourself or with your own trades. It suits confident DIYers and anyone who wants to spread the cost.
See our shell loft conversion pageNot sure which?
Every house is different — we check what suits yours before you commit to anything.
Book a free loft surveyWhich suits your home
| Type of house | Options we usually look at first |
|---|---|
| Mid-terrace (Victorian or Edwardian) | Rear dormer, L-shaped dormer, mansard |
| End-of-terrace or semi-detached with a hipped roof | Hip-to-gable, often with a rear dormer |
| Detached | Dormer, hip-to-gable on one or both sides, or Velux where head height allows |
| Newer home with a trussed roof | Trussed roof conversion with a dormer or roof windows |
| Conservation area or listed building | Velux or mansard, subject to planning permission |
This is a starting point. The final recommendation depends on your head height, roof structure, the layout you want and what your council allows.
What you need to know
Many loft conversions on houses in England can be built under permitted development, without a planning application, provided they stay within set limits. The main ones are:
Permitted development does not apply to flats and maisonettes, and it is restricted in conservation areas and where the council has made an Article 4 direction. Mansard conversions usually need planning permission. Where a loft is permitted development, we can apply for a Lawful Development Certificate so you have written confirmation from the council. We check which route applies to your house at the survey.
What you need to know
Every loft conversion that creates a habitable room needs building regulations approval, whether or not it needs planning permission. The work is inspected at key stages and signed off at the end. The main areas are:
We arrange the building control inspections at each stage and hand you the completion certificate at the end.
What you need to know
If you live in a terraced or semi-detached house, a loft conversion usually involves work on the shared wall, such as cutting pockets for steel beams or building up a gable. The Party Wall etc. Act 1996 requires you to give your neighbours written notice before this work starts. If they agree, work can go ahead; if not, a party wall surveyor prepares an award. We tell you at the survey whether notices are needed and build the time into the programme.
Cost
Every loft is priced individually after the survey, and you receive a written, itemised quote. These are the main factors:
A Velux conversion costs less than a dormer, and mansard and L-shaped conversions cost the most, because of the amount of roof that is rebuilt.
Trussed roofs and complex roof shapes need more steelwork and engineering.
A simple straight flight costs less than a winding or bespoke stair, or one that means reworking the floor below.
Plumbing, drainage and tiling add cost. Where the waste cannot run by gravity, a Saniflo installation may be needed.
The number and size of roof windows, dormer windows and any Juliet balcony.
Flooring, built-in storage, lighting and decoration.
The height and position of the house, and whether scaffolding needs to go over neighbouring land.
Structural calculations, building control, and planning or party wall costs where they apply.
No guesswork: you receive a written, itemised quote after your free survey, with payments staged against clear points in the work.
Timescale
A Velux conversion is usually the quickest, because the roof shape does not change. Dormer and hip-to-gable conversions take longer, and mansard and L-shaped conversions longest, because more of the roof is rebuilt. Most of the early work happens from scaffolding and inside the loft, so you can usually stay at home until the stage where the new staircase is connected. Your quote includes a programme showing each stage and how long it should take.
09 — One team
A loft conversion needs far more than a builder. We coordinate every trade it involves:
New circuits, sockets, lighting and interlinked smoke alarms through our domestic electrical installation service.
Extending the heating with radiator installation, and checking your boiler can cope with the extra room.
An en-suite shower room, basin and WC through our bathroom plumbing service.
En-suite walls and floors through our bathroom tiling service.
Plastering, painting and finishing, so the room is ready to use on the day we hand over.
Process
Every stage is planned before we start, with one project manager from survey to sign-off.
we measure the loft, check the roof structure and talk through what you want the space for.
you receive an itemised quote and a programme; drawings and structural calculations are prepared.
planning or a Lawful Development Certificate where needed, building regulations approval and party wall notices.
scaffolding, steel beams, floor, dormer or gable, and roof. The house stays weathertight throughout.
wiring, plumbing and heating pipework, then insulation and plasterboard.
the new staircase goes in, followed by plastering, tiling, second fix and decorating.
building control completion, electrical and other certificates, and a walk-round of the finished room.
Areas
We build loft conversions across London, with a particular focus on east and south-east London, where the housing suits particular loft types. Edwardian terraces and interwar semis are common in Ilford, and Dagenham's Becontree estate has many end-of-terrace houses suited to hip-to-gable conversions. East Ham's Victorian terraces suit L-shaped and rear dormer conversions, while Orpington's semis and detached homes often suit hip-to-gable and dormer lofts. See our pages for builders in Ilford, builders in Dagenham, builders in East Ham, builders in Orpington and builders in Barking, or all the areas we cover.
FAQs
Can't see your question? Call or WhatsApp us — we're happy to help before you book.
It depends mainly on the type of conversion, the size of the loft, the roof structure and whether you add an en-suite. Velux conversions are usually the lowest cost, dormers sit in the middle, and mansard and L-shaped conversions cost the most. We give you a fixed, itemised quote after a free survey.
Often not. Many loft conversions on houses fall under permitted development if they stay within volume, position and design limits. You will need planning permission for most mansards, for flats and maisonettes, and in many conservation areas or where an Article 4 direction applies. We check your property at the survey.
A Velux conversion is usually the quickest, and dormer and hip-to-gable conversions take longer. Mansard and L-shaped conversions take the longest because more of the roof is rebuilt. Your quote includes a programme showing each stage, and most of the early work happens without disturbing the rest of the house.
As a rule of thumb, around 2.2 metres from the top of the ceiling joists to the underside of the ridge makes a conversion straightforward. Lower lofts can often still be converted by adding a dormer or mansard, or by lowering the ceiling of the room below. We measure it at the survey.
An extra bedroom, especially with an en-suite, usually adds to a home's value and makes it more appealing to buyers, often more than the cost of moving to a bigger house. How much value depends on your area and the finished quality, so an estate agent can give the best local guide.
The best type depends on your house and your plans. Velux suits lofts with good head height, dormers suit most terraces, hip-to-gable suits semis and end-terraces, and mansards and L-shaped conversions give the most space on Victorian terraces. We recommend the right option at your free survey.
One team, every trade
Next step
Tell us about your house and what you would like to use the loft for. We will survey the loft, recommend the right type of conversion and send you a written, itemised quote.
Send us photos of your loft on WhatsApp to get started, or use our contact form.
