London's Loft Conversion Specialists

Loft Conversions
Across London

All types. All boroughs. Fully managed from survey to sign-off. Velux rooflight, rear dormer, L-shaped dormer, hip-to-gable, mansard. 10/10 on Checkatrade.

From £35,000

Rear dormer

8–14 wks

Typical programme

15–25%

Property value uplift

Independently reviewed

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Loft conversions we've completed

Photographs from rcbGroup loft projects — bedrooms with rooflights and dormer glazing, en-suites, new staircases and eaves storage.

Loft conversion bedroom with rooflights, fitted storage and full-height glazing — rcbGroup project — Loft bedroom with rooflights and glazing

Loft conversion bedroom with rooflight, oak doors and fitted drawers — rcbGroup project — Loft bedroom with oak doors and fitted drawers

Loft conversion bedroom with desk area and glazed dormer wall — rcbGroup project — Loft bedroom with dormer glazing

Loft conversion bedroom with rooflight and new oak door — rcbGroup project — Loft bedroom with rooflight

Loft en-suite with metro tiles, rooflight, bath and heated towel rail — rcbGroup project — Loft en-suite with rooflight

Loft bathroom with white metro tiles, black grout and navy walls — rcbGroup project — Loft bathroom, metro tiles and navy walls

New staircase with black balustrade and exposed brick wall — rcbGroup project — New staircase and exposed brick

New staircase to the loft conversion with black painted treads — rcbGroup project — Staircase to the loft

Loft bedroom with two rooflights and fitted wardrobes — rcbGroup project — Loft bedroom with two rooflights

Loft room with rooflights and built-in eaves storage — rcbGroup project — Eaves storage in the loft

Loft bedroom with rooflights, pendant lights and fitted cupboards — rcbGroup project — Loft bedroom, pendants and cupboards

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Inside a loft conversion build

Photos from an rcbGroup loft conversion on site: new rafters, roof windows fitted, timber framing and insulation, then boarded out ready for plaster.

New roof rafters framing a loft conversion against a clear sky — rcbGroup project — Loft roof rafters going up

Installing a roof window in a newly tiled loft roof — rcbGroup project — Roof window being fitted

Loft conversion timber framing with two roof windows fitted and insulation going in — rcbGroup project — Loft framing and roof windows

Timber stud walls and roof windows inside a loft conversion under construction — rcbGroup project — Loft stud walls and roof windows

Boarded loft room with two roof windows, ready for plastering — rcbGroup project — Loft boarded and ready for plaster

Timber stud partitions framing new rooms — rcbGroup project — New stud partitions

Loft conversions on video

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Loft conversion

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Loft conversion and property management in Bromley

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Design visuals from our projects

3D visuals prepared for rcbGroup residential projects — bedrooms, en-suites and double-height spaces of the kind a loft conversion or reconfiguration can create. These are design renders, not photographs of finished work.

3D visual of a double-height living space with a glazed gallery landing and feature pendant lighting — Double-height living space with glazed gallery

3D visual of a master bedroom with a feature panelled wall, wall-mounted TV and en-suite door — Master bedroom with feature wall and en-suite

3D visual of floating timber stair treads with vertical LED wall lighting — Floating stair with vertical LED lighting

3D visual of a bedroom with a built-in study desk and two windows — Bedroom with built-in study area

3D visual of a staircase with timber treads rising from an open-plan living area — Staircase from the living area

3D visual of an open-plan space with a mezzanine, open-tread staircase and breakfast bar — Open-plan space with mezzanine and open-tread stair

Types of Loft Conversion

The right type depends on your roof structure, head height, property type, and planning position. We advise at the project review.

Velux / Rooflight Conversion

Simplest type

Detached and semi-detached properties with good existing head height

From £18,000

5–7 weeks

The most straightforward conversion — roof windows are installed within the existing roof slope. No new roof structure. Best where head height is generous and maximum space is not required.

✓No change to roof shape
✓Always within Permitted Development
✓Least disruptive option
✓Best head height: 2.4m+ from ridge

Rear Dormer Conversion

L-Shaped Dormer Conversion

Maximum terrace space

Victorian terraced houses with a rear back addition / outrigger

From £55,000

10–14 weeks

A rear dormer combined with a dormer over the outrigger (back addition), creating an L-shape when viewed from above. Delivers the maximum loft space possible on a standard terraced property.

✓Maximum space for terraces with outriggers
✓Two dormer areas (main roof + outrigger)
✓Party wall notices on both sides
✓Usually within Permitted Development

Hip-to-Gable Conversion

Best for semi-detached

Semi-detached and detached houses with hipped roof ends

From £45,000

10–14 weeks

The hip end (sloping side) is replaced with a vertical gable wall, opening up a much larger loft space. Almost always combined with a rear dormer for a full conversion.

✓Increases loft volume significantly
✓Usually within Permitted Development for semis
✓Always combined with rear dormer
✓Party wall notice required

Mansard Conversion

Highest volume

Victorian terraced houses in central and west London, Conservation Areas

From £70,000

14–20 weeks

The entire rear slope is rebuilt as a near-vertical (70°) face with a flat top. Creates the maximum possible volume. Common in Central and West London. Usually requires full planning permission.

✓Maximum volume of any conversion type
✓Usually requires full planning permission
✓Grey zinc or lead cladding typical
✓Most expensive type

Read our detailed loft conversion guide →

What Might Your Loft Conversion Cost?

Use the estimator to get a rough idea of your budget range before booking a survey. Adjust the type, size, and finish level to see how costs change.

✓ All figures based on real rcbGroup project data

✓ Excludes second-fix materials (client-supplied)

✓ A detailed, itemised estimated quotation follows your project review

✓ Planning, structural engineer, Building Control all managed by rcbGroup

Loft Conversion Estimator

Adjust the options to get a quick ballpark — not a quote, but a useful starting point.

Project type

Approx. size

Finish level

Want more detail? Try the full cost calculator →

What's Included

A complete rcbGroup loft conversion package — everything from structural engineer to Building Control sign-off.

✓Structural engineer design (floor structure, padstones, dormer frame)

✓Building Regulations application and all inspection bookings managed

✓Scaffold erection and strike (all stages)

✓All roofing works: dormer structure, felt, battens, tiles/slates, lead flashings

✓Roof window installation (Velux or equivalent)

✓New floor structure throughout loft

✓Full staircase from first floor to loft

✓Internal stud walls with plasterboard

✓Insulation: roof, walls, floor to Building Regs Part L standard

✓First-fix electrical circuits (lighting, power, smoke alarms)

✓First-fix plumbing (en-suite waste and supply runs)

✓Dormer windows or Juliet balcony doors

✓Plasterboard and skim throughout

✓En-suite bathroom installation (labour only — client supplies suite)

✓Fire doors to loft staircase

✓Written project documentation

✓CDM Health and Safety File at completion where required

Standard Exclusions

—Second-fix materials: sanitaryware, tiles, light fittings, taps, shower enclosure (client-supplied)

—Carpet — rcbGroup does not supply or install carpet

—Architect/Structural Engineer fees (if not part of design-and-build package)

—Lawful Development Certificate application fee (£206)

—Party wall surveyor fees (where required)

—Planning Application fee (where full planning is required)

Common Associated Works

Most loft conversions include associated works on the existing property. It's efficient to complete these at the same time — same trades, same programme.

En-Suite Bathroom

Almost every loft conversion includes a new en-suite shower room or bathroom. Client supplies all second-fix materials (suite, tiles, fittings). rcbGroup installs.

Staircase

A proper staircase is required. In many London terraces, accommodating the loft stair requires reconfiguring the first-floor layout — sometimes with a structural alteration.

Consumer Unit Upgrade

Adding circuits for the new loft may require upgrading the main distribution board. We advise during the pre-construction stage.

First Floor Refurbishment

With scaffold up and trades on site, many clients refurbish the existing first-floor bathroom and landing at the same time. Efficient use of the disruption period.

How It Works

Project Review

We visit the property, assess feasibility, measure up, and understand your brief. No obligation.

Itemised Estimate

Itemised estimated quotation, with inclusions and exclusions shown. We clarify planning position, party wall requirements, and Building Control route.

Pre-Construction

Architect drawings, Structural Engineer, PD/LDC or planning application, Building Regs submission. We coordinate everything.

Build & Sign-Off

Structured programme, dedicated site manager, Building Control inspections managed, Completion Certificate issued.

Speak to the team today

Not sure which loft conversion is right for your home?

Call us — we advise on the right type, planning route and realistic budget. No commitment required.

Call +44 7359 872594 Book a Free Review

Loft Conversion FAQs

Does a loft conversion need planning permission?▼

Most don't. Under Permitted Development, rear dormers and hip-to-gable conversions proceed without a full planning application for houses (not flats), within volume limits (40m³ terraces, 50m³ semi-detached and detached). Mansard conversions almost always need planning permission. We confirm the planning position for your property before any commitment.

Can every property have a loft conversion?▼

No — head height is the main constraint. You typically need at least 2.2m from the existing floor joist to the underside of the ridge for a conversion to be feasible. We assess this at the project review. Trussed-rafter roofs (post-1960s construction) require structural assessment before a conversion is designed.

Do I need to move out during a loft conversion?▼

For most loft conversions, no. The most vulnerable period is 5–10 days while the roof structure is open before the dormer is weathertight. Our teams work quickly through this stage with temporary waterproofing. Most clients stay in the property throughout.

Do I need a party wall agreement for a loft conversion?▼

Usually yes, if you are in a terrace or semi-detached house. Most loft conversions involve inserting steel beam padstones into or adjacent to the party wall — this triggers the Party Wall etc. Act 1996. We advise on the required notices and can recommend surveyors.

How much does a loft conversion add to my property value?▼

Adding a bedroom and bathroom typically adds 15–25% to property value, depending on location and the quality of the conversion. In many London postcodes, the uplift exceeds the build cost.

See all FAQs →

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