House Renovation Hertfordshire 2026: Costs, What a Whole-House Renovation Involves and a Real LCCL Project
By Anderson & the LCCL Construction Team | Finchley N3
A whole-house renovation in Hertfordshire usually starts with a house that was last touched in the 1980s: a 1930s semi in St Albans, a 1960s detached in Harpenden or Potters Bar, an Edwardian villa in Hertford or Bishop's Stortford. The structure is sound, the layout is wrong and everything behind the plaster is at the end of its life. We design and build renovations like these from Finchley N3, with Hertfordshire towns from Barnet and Potters Bar up to St Albans, Watford and Welwyn Garden City inside our normal working area.
This guide gives our 2026 figures for a whole-house renovation, explains what is and is not inside them, and uses our Bohun Grove project in East Barnet EN4 — the renovation, extension and loft that won the LABC Building Excellence Award 2024 for Best Residential Extension in London — to show what a complete programme looks like on the Hertfordshire border.
What a house renovation costs in Hertfordshire (2026)
Hertfordshire postcodes (AL, WD, SG, HP and EN6–EN11) sit slightly below our London base band, so the ranges below are a fair guide; the instant estimate adjusts them for your own postcode. Figures are inc. VAT with the ex-VAT figure in brackets.
Whole-house renovation (80–140 m²): £60,000 – £180,000 (£50,000 – £150,000 + VAT). As a per-m² guide, £840 – £1,320 per m² inc. VAT (£700 – £1,100 + VAT) covers strip-out, new services, replastering, new floors and ceilings where needed and making good, to a shell-and-plaster finish.
Ground-floor or first-floor renovation on its own: the same £700 – £1,100 + VAT per m², typically 40–70 m² downstairs and 35–60 m² upstairs.
New kitchen, supplied and fitted (units, worktops, sink and tap, connections to existing points): a medium kitchen is £12,000 – £17,400 inc. VAT (£10,000 – £14,500 + VAT) at economy level, £22,000 – £31,000 inc. VAT at mid-range, before appliances, flooring and tiling.
New bathroom or en-suite: £14,400 – £24,000 inc. VAT each at economy level, more at mid-range and high-end specification.
Full rewire and replumb are priced per house by bedroom count and are nearly always worth doing while the walls are open rather than two years later.
Add the lines together for your own house — renovation by floor area, then kitchen, bathrooms, rewire and replumb — and you have the budget before any extension or loft. Our home renovation cost guide breaks every room down, and the instant estimate builds your own combination.
What is inside a whole-house renovation — and what is not
Our renovation line covers the house as it stands: strip-out, new electrics and plumbing first fix, new heating, replastering, new floor and ceiling finishes where the old ones have failed, internal doors, skirting and architraves at the fully finished level, and decoration at the decorated level. It does not include the kitchen and bathroom fittings (separate lines), structural openings to knock rooms together, new windows, a loft conversion or an extension, planning and building control fees, or party wall surveyors. Each of those is priced as its own line so you can see what the renovation itself costs before you decide how far to go.
The order matters. If you are thinking of an extension or loft as well, design them together with the renovation. The steel for an open-plan ground floor, the drainage for a new bathroom and the staircase for a loft all go in during the strip-out — doing them afterwards means opening the same walls twice.
Planning and building regulations in Hertfordshire
A renovation that stays inside the existing walls does not normally need planning permission, with the usual exceptions for listed buildings and conservation areas — Hertfordshire has many of both, in St Albans, Harpenden, Hertford, Berkhamsted and the villages. Replacement windows, a change of external materials or a new front door on a house with an Article 4 direction can need consent, so check with the district council (St Albans, Dacorum, Welwyn Hatfield, Hertsmere, Watford, Three Rivers, East Herts, Broxbourne, North Herts or Stevenage) before ordering anything.
Building regulations apply regardless: electrical work, new bathrooms, structural alterations, replacement windows, new heating and any change to the thermal envelope all need sign-off. We run every project through local authority building control from the first inspection to the completion certificate — the same inspectors who nominate projects for the LABC awards. Our guide to building regulations for lofts and extensions explains the process.
A real project: Bohun Grove, East Barnet EN4
Bohun Grove is a 1930s semi-detached house on the Hertfordshire border in East Barnet EN4. The whole house was renovated — new windows throughout, enlarged bedrooms, two new bathrooms, new lighting and electrics — alongside a rear extension with an open-plan kitchen under skylights and full-height glazing, a hip-to-gable loft conversion with a master suite, a regulated outbuilding and landscaping that was designed with the extension so the inside and outside read as one space. The London Borough of Barnet's building control surveyor inspected the project throughout and put it forward for the LABC Building Excellence Awards, where it won Best Residential Extension in London in 2024. The project page has the full photograph set and our award post tells the story.
Anderson's advice
“Clients budget for kitchen units but forget structural steelwork changes when opening up ground floor walls.” In a Hertfordshire renovation this is the single most common gap between the first budget and the real one. Opening the kitchen into the dining room, taking out the wall between the two reception rooms, moving a bathroom — each is a structural change with an engineer's calculations, steel, temporary works and building control inspections behind it. On a 1930s semi the steelwork alone typically runs to £4,000 – £12,000 + VAT. Put it in the budget at the start; it is the part of the job that gives you the house you actually want.
Why design & build for a Hertfordshire renovation
As LABC Building Excellence Award Winners 2024 for Best Residential Extension in London — and London Regional Winners again in 2026 for Best Conversion or Alteration to an Existing Home — we design and build renovations with the architectural design, structural engineering, building control and construction under one contract and one point of contact — so the kitchen layout, the steel and the wiring are decided together rather than by three separate firms. Every project carries a 12-month workmanship guarantee and a 10-year LABC structural warranty. If an extension is part of the plan, see our St Albans, Harpenden and Hertford extension guides.
What our clients say
“I highly recommend LCCL Construction. From the start of discussing ideas and planning I can tell you they were very professional and efficient. I had my kitchen and loft done a year ago now and am absolutely thrilled! Exactly what I wanted!”
— Nadya Christou, Google Reviews
Frequently asked questions
How much does it cost to renovate a house in Hertfordshire in 2026?
A whole-house renovation to a shell-and-plaster finish is £60,000 – £180,000 inc. VAT (£50,000 – £150,000 + VAT) for a typical 80–140 m² house, about £840 – £1,320 per m² inc. VAT. Kitchens, bathrooms, structural openings, windows and any extension or loft are priced as separate lines on top.
Do I need planning permission to renovate a house in Hertfordshire?
Not for internal work on an ordinary house. Listed buildings, conservation areas and houses with an Article 4 direction need consent for many external changes, and any extension or roof alteration is assessed separately. Building regulations approval is needed for the electrics, plumbing, structure, windows and heating whatever the planning position.
How long does a whole-house renovation take?
Allow 8–12 weeks for design, structural engineering and building control, then 12–20 weeks on site for a renovation of 80–140 m². Adding an extension or loft to the same programme extends the build but is faster and cheaper than doing them as separate projects later.
Get a figure for your own project
To book a free 30-minute consultation call about your renovation in Hertfordshire, call LCCL Construction on 020 8037 7332 or get an instant estimate online — six questions, about two minutes, and you see a real range for your postcode on screen. Finchley N3 based, covering all of London and Hertfordshire.
One team, one contract, one point of contact — from first sketch to handover.
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