Two-storey extension plans and drawings in Kent

Kent at a glance

Nation: England
Price region: South East England
Postcode areas: BR, CT, DA, ME, TN
Towns covered: 31 listed below, plus surrounding villages
Site visits: Free, no obligation

What a set of extension plans involves

This service suits you if you want clear, accurate plans for a two-storey extension, whether to apply for planning, check permitted development or get build prices. You get a measured survey, sketch options with guide costs, a chosen design developed into planning drawings and, if you go ahead, building regulations drawings coordinated with the structural engineer. Because we also build, the drawings are prepared with the build in mind.

Kent towns we list: Maidstone (ME14), Gillingham (ME3), Chatham (ME4), Tunbridge Wells (TN1), Folkestone (CT18) and Margate (CT9). Every other address in Kent is covered as well.

Fees

Planning drawings (survey and design) are a guide of £2,000–£3,500 and building regulations drawings and specification £1,500–£4,000, with your design stage priced in writing before it starts.

Rules in England

In England, the plans support either a householder application, costing £548 (or £575 for applications made from 8 December 2026), or a lawful development certificate for permitted development, costing £274 (about £288 for applications from 8 December 2026). They must show the extension's relationship to the original house, the boundaries and neighbours, because two-storey rear permitted development depends on the 3 m and 7 m limits.

Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.

Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.

The Party Wall etc. Act 1996 applies, so notices may be needed for work on or near a shared wall or boundary.

Getting the design right

Planning drawings versus building regulations drawings

Planning drawings show what the extension looks like and how it affects neighbours. Building regulations drawings show how it is built: foundations, structure, insulation, fire safety, ventilation and drainage. Most two-storey extensions need both, prepared at different stages.

Start with a measured survey

Accurate drawings depend on accurate measurements of the house, the boundaries and neighbouring windows. We measure inside and out, note levels, drains and trees, and record the original house so permitted development limits can be checked against the right starting point.

How we work in Kent

Look at the house
We start in Kent with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in England before drawing in detail.
Structure and building control
A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.
Build and hand over
We manage the build from groundworks to decoration-ready finish and hand over with the completion paperwork.

Towns we cover in Kent

Two-storey extension plans and drawings in Kent: questions

How long do extension plans take to prepare?

Survey, design and planning drawings usually take 4 to 8 weeks, depending on how many options you want to explore. Technical design, structural calculations and building control approval take a further 4 to 8 weeks, and this can overlap with the planning decision period.

Can I use plans from a previous owner's planning permission?

Sometimes. If the permission is still valid, usually within three years of the decision in England, you can build to it. The drawings may still need updating for building regulations, and the design may not suit your needs. We check old plans and permissions at the free site visit.

Do the plans include structural calculations?

Not at planning stage. Structural calculations and beam design are prepared by a structural engineer once the design is agreed, and they form part of the building regulations package. We coordinate the engineer's work with the drawings so steel sizes and floor depths match.

Neighbouring areas

All extension services in Kent · About two-storey extension plans and drawings