Dormer · Hip-to-Gable · Mansard · Velux
Loft Conversions in Kent
Tonbridge-based builders converting lofts across Kent, from the steelwork and dormer structure to the finished bedroom and en-suite. 5★ Google rated, 20+ years experience.
Typical Cost
From £25,000
Rear dormer £40,000–£60,000
Typical Build Time
8–14 weeks
Up to 18 for a mansard
Scope
Steelwork, dormer or gable structure, staircase, insulation, electrics, plumbing and finish, with Building Control sign-off
Free, no-obligation written quote
Loft Conversion Builders for Kent Homes
A loft conversion is usually the cheapest way to add a proper bedroom and bathroom to a Kent home. It costs significantly less per square metre than a ground-floor extension, it is almost always cheaper than moving, and most of the work happens above your head while you carry on living in the house.
Carey Brothers & Sons has built across Kent for more than twenty years. A loft conversion is structural work first and decoration second: steel beams, new floor joists, a dormer or gable built off the existing roof, and a staircase that has to land in the right place on the floor below. We carry out the structural carpentry and brickwork with our own team, and we bring in a structural engineer before we price, because a quote without calculations is a guess.
We will also tell you plainly when a loft is not the answer. If the headroom is too low for the room you want, or the family really needs a bigger kitchen, an extension will serve you better, and we would sooner say so at the first visit.
Get a Free Quote
Tell us about your house and what you want from the loft. We'll call you back to arrange a free site visit and a written quote.
Types and Prices
Loft Conversion Costs in Kent: 2026 Guide
The type of conversion sets the price. The right type depends on your roof shape, the headroom you have now and whether the house is in a conservation area.
| Conversion type | Typical cost | What it involves |
|---|---|---|
| Velux / rooflight | £25,000–£40,000 | Existing roof shape kept, rooflights added. Needs about 2.3m of headroom. |
| Rear dormer | £40,000–£60,000 | The most common type in Kent. Full headroom across the rear of the loft. |
| L-shape dormer | £55,000–£80,000 | Two joined dormers on Victorian and Edwardian terraces with a rear return. |
| Hip-to-gable | £50,000–£75,000 | The sloping side of a hipped roof rebuilt as a vertical gable, usually with a rear dormer. |
| Mansard | £65,000–£100,000+ | Near-vertical rear roof slope giving almost a full extra storey. Usually needs planning. |
Indicative costs for loft conversions in Kent in 2026. They include the structural conversion, staircase, plumbing, electrics, plastering and finish. A bathroom suite and fitted wardrobes are typically £4,000–£10,000 extra.
Local Knowledge
Planning Permission and Building Regulations
Most Kent loft conversions do not need planning permission. All of them need Building Regulations approval. Here is where the line falls.
When permitted development applies
A rear dormer is usually permitted development if it adds no more than 40 cubic metres to a terraced house or 50 cubic metres to a semi-detached or detached house, does not extend forward of the front roof slope, uses materials similar to the existing house, and has obscure glazing in any side-facing window. No balconies or raised platforms.
When you need full planning permission
Conservation areas cover most of central Tunbridge Wells, parts of Sevenoaks and Tonbridge and much of Chislehurst, and permitted development rights are usually restricted there. Most mansard conversions need permission, as do houses that have already used up their permitted development allowance. Allow £2,000–£4,000 for planning and design fees and twelve to sixteen weeks for a decision.
Building Regulations
Every loft conversion is full Building Regulations work: structural calculations, a fire-protected escape route with a fire door at the top of the stairs, insulation to current standards and Building Control inspections. These are included in our quotes. Be wary of a cheaper quote that leaves any of them out, because without sign-off you cannot sell or remortgage.
Party walls
On terraced and semi-detached houses the new steel beams usually bear on or near the party wall, so a Party Wall Agreement is needed. Notice must be served at least two months before work starts, and a surveyor typically costs £900–£1,500 per neighbour.
Planning Permission in Kent: Full Guide
Thresholds, fees, pre-application advice and timelines for every Kent planning authority.
How We Work
From First Visit to Finished Room
A loft conversion runs in four stages. You will know what is happening at each one and what it costs.
Site visit and feasibility
We measure the headroom, look at the roof structure and the staircase position, and tell you which type of conversion suits the house. You get an honest view on whether permitted development is likely to apply before any drawings are paid for.
Design, structural calculations and approvals
A structural engineer's calculations are essential for any loft conversion and we will not quote properly without them. Where planning permission is needed your designer submits the application; where it is not, we still go through Building Regulations approval and serve Party Wall notices on neighbours where required.
Structure and weathertight shell
Scaffold up, steel beams and new floor joists in, then the dormer, gable or mansard structure built and made weathertight. Most of this is done from outside, so the house stays liveable until the staircase opening is cut.
Fit-out and sign-off
Staircase, insulation, first-fix electrics and plumbing, plastering, bathroom, second fix and decoration. Fire doors and the protected escape route are completed, Building Control inspects, and you receive the completion certificate you will need when you sell or remortgage.
Why Carey Brothers
Why Kent Homeowners Choose Us for Their Loft
Structural work by our own team
Roof carpentry, steelwork and brickwork are carried out by our own tradespeople, so the structure and the finish are one team's responsibility.
Fully insured, 20+ years trading
We have built continuously across Kent since 2004 and are fully insured. References and visits to recent projects are available on request.
An itemised quote, not a guess
Site visit, structural engineer's calculations, an itemised price, the planning position and a realistic programme, all in writing before you commit.
Signed off properly
Fire safety, insulation and structure are built to Building Regulations and inspected by Building Control, and you receive the completion certificate.
Where We Work
Loft Conversions Across Kent
Loft conversions in Tonbridge, Sevenoaks, Tunbridge Wells, Maidstone and the towns and villages between them. Choose your area for local planning notes and recent projects.
Loft conversions in Tonbridge
1930s semis suit hip-to-gable and rear dormers; conservation rules apply in the centre
Loft conversions in Tunbridge Wells
Conservation areas are common, so mansard and rooflight designs
Loft conversions in Hildenborough
Hip-to-gable conversions on 1930s and 1950s houses
Loft conversions in Sevenoaks
Victorian terraces suit L-shape dormers; mansards on period homes
Loft conversions in Weald
Kent, TN14
Loft conversions in Chislehurst
L-shape dormers on Victorian terraces; conservation areas
Loft conversions in Borough Green
Kent, TN15
Loft conversions in West Malling
Hip-to-gable and rear dormers
Loft conversions in Maidstone
Rear dormers and hip-to-gable on semis and detached houses
Loft conversions in Ashford
Rear dormers on standard semis and terraces
Recent Work
Roof and Upper-Storey Projects in Kent
The structural skills a loft conversion depends on, shown in two recent Kent projects: a timber-framed upper storey with a hand-cut roof, and a first-floor extension carried on a steel frame.
Helpful Guides
Loft Conversion Reading
Detailed guides on loft costs, lofts against extensions, planning and renovation budgets.
Loft Conversion Costs in Kent: Complete 2026 Price Guide
How much does a loft conversion cost in Kent in 2026? Type-by-type pricing (Velux, dormer, hip-to-gable and mansard) plus what makes a Kent loft conversion more or less expensive.
Read more about Loft Conversion Costs in Kent: Complete 2026 Price GuideExtension vs Loft Conversion: Which is Right for Your Kent Home?
Comparing extensions and loft conversions for adding space to your Kent home. Costs, planning permission, and which option delivers better value.
Read more about Extension vs Loft Conversion: Which is Right for Your Kent Home?Do I Need Planning Permission? Kent Homeowner's Guide 2026
A clear, practical guide to planning permission and permitted development in Kent: covering extensions, outbuildings, loft conversions, and local council specifics.
Read more about Do I Need Planning Permission? Kent Homeowner's Guide 2026House Renovation Costs in Kent: Room-by-Room Breakdown
A practical guide to renovation costs in Kent for 2026: covering kitchens, bathrooms, bedrooms, and whole-house projects with realistic budgets and expert advice.
Read more about House Renovation Costs in Kent: Room-by-Room BreakdownCommon Questions
Loft Conversions Kent: FAQ
1How much does a loft conversion cost in Kent?
In 2026 a Velux or rooflight conversion in Kent typically costs £25,000–£40,000, a rear dormer £40,000–£60,000, an L-shape dormer £55,000–£80,000, a hip-to-gable £50,000–£75,000 and a mansard £65,000–£100,000 or more. Those figures cover the structural conversion, staircase, plumbing, electrics, plastering and finish. A bathroom suite and fitted wardrobes are usually extra, typically £4,000–£10,000.
2Do I need planning permission for a loft conversion in Kent?
Most rear dormer loft conversions fall under permitted development, provided the added volume stays within 40 cubic metres on a terraced house or 50 cubic metres on a semi-detached or detached house, nothing extends forward of the front roof slope, and materials match the existing house. You will need full planning permission in conservation areas, which cover much of central Tunbridge Wells, parts of Sevenoaks and Tonbridge and much of Chislehurst, and for most mansard conversions.
3How long does a loft conversion take?
A Velux conversion takes around six to eight weeks. Allow ten to fourteen weeks for a standard dormer and fourteen to eighteen weeks for a hip-to-gable or mansard. The steelwork and dormer structure usually take the first three weeks; the rest is internal fit-out, plumbing, electrics, plastering and external finish.
4Is my loft suitable for conversion?
The main test is headroom. You need about 2.3 metres from the top of the existing ceiling joists to the underside of the ridge for a rooflight conversion to give a usable room. Lower roofs can often still be converted with a dormer, hip-to-gable or mansard, which create full-height space. The roof structure matters too: trussed roofs built after the 1960s need new steel beams and joists, while older cut roofs can throw up surprises such as undersized timbers. We check all of this at the first visit.
5Do I need a Party Wall Agreement for a loft conversion?
Yes, in almost all terraced and semi-detached Kent houses, because the new steel beams usually rest on or near the party wall. A Party Wall Surveyor typically charges £900 to £1,500 per neighbour, and notice has to be served at least two months before work starts, so it is worth starting early.
6Does a loft conversion add value to a Kent home?
Typically 15 to 20 percent in West Kent towns such as Sevenoaks and Tunbridge Wells, and 10 to 15 percent across the rest of the county. A loft with a bedroom and en-suite adds materially more than a single room without a bathroom.
7Which areas of Kent do you cover for loft conversions?
We carry out loft conversions across Tonbridge, Sevenoaks, Tunbridge Wells, Maidstone, Ashford, Hildenborough, West Malling, Borough Green, the Weald and Chislehurst. Our base is 24 Dodd Road in Tonbridge. Call 07879 447975 or use the contact form for a free site visit and a written quote.
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