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Building regulations for extensions across Kent

We prepare building regulations for extensions for homes across Kent, on their own or as the first stage of a full design and build project.

  • Guide priceFrom £1,000 inc VAT
  • Approval routeFull plans or building notice
  • Towns covered23
  • Site visitFree, no obligation
Builder installing a steel beam over a new rear opening on acrow props

What it costs in Kent

These are guide fees for Kent, adjusted for South East England (×1.12) and including VAT. Council application and inspection fees are paid separately.

OptionWhat it coversGuide price
EssentialBuilding regulations drawings for a simple single-storey extension£1,000 – £2,050
StandardDrawings plus structural calculations£1,450 – £2,950
PremiumComplex or two-storey pack with energy calculations£2,450 – £4,300

Our design fee only. Building control charges are set by your council (or, in England and Wales, a registered building control approver) and quoted separately.

Want a range for your exact size? The guide-price tool takes about a minute.

Covering Kent

Towns we cover in Kent include Maidstone, Gillingham, Chatham, Tunbridge Wells, Folkestone, Margate, Ashford, Kent, Canterbury. The South East has a broad mix of 1930s semis, post-war estates, newer developments and period cottages, and many houses have enough garden for a generous rear extension.

When it helps

  • Every extension, whatever the planning route
  • Homeowners using their own builder who need the drawings
  • Glass-heavy designs that need energy calculations

Planning rules that apply in Kent

Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.

The planning position for a specific Kent address depends on its history and any designations, which is why we check it at the first visit.

Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.

If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.

Applications are decided by the local planning authority (your district, borough or unitary council).

What happens next

Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.

  1. Free site visit

    We visit your Kent home, measure up, talk through what you want and check the planning position.

  2. Design and approvals

    Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.

  3. Fixed written price

    The price is fixed in writing once the design is settled, with a clear programme and payment stages.

  4. Build and sign-off

    Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.

Common questions in Kent

Will my neighbours in Kent be involved?

If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.

How long does this take for a Kent home?

2–5 weeks for drawings, depending on the council and the complexity of the project.

Do you cover all of Kent?

Yes, across the whole of Kent. Site visits are free and there is no obligation.

What are the insulation standards for an extension?

In England, new walls in an extension should achieve a U-value of 0.18 W/m²K, roofs 0.15 and floors 0.18, with windows at 1.4 and rooflights at 2.2. Wales, Scotland and Northern Ireland set their own figures.

Full plans or building notice?

A full plans application gets the drawings checked before work starts, which we usually recommend for extensions. A building notice is quicker to submit but carries more risk if something needs changing on site.

Book a free site visit in Kent

We will measure up, check the planning position and give you honest guide figures.

  • Free, no-obligation site visit
  • Planning route checked before you spend on drawings
  • Written price once the design is agreed
  • Building control sign-off at the end

Prefer to talk? Call 0800 088 6341 or .

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