Home › Extension Plans in Denbighshire

Extension plans across Denbighshire — vale, hills and coast.

Ruthin, Denbigh, St Asaph, Prestatyn, Rhyl and the villages between — drawings, planning and building regs from a specialist who works the county every month.

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From the Vale of Clwyd to the coast.

Denbighshire runs from market-town stone cottages in Ruthin and Denbigh to seaside semis in Prestatyn and Rhyl — and the county has more than its share of conservation areas and older buildings where extension design takes real judgement. Welsh Permitted Development rules apply, the householder fee is £585 when permission is needed, and Denbighshire County Council determines most applications within eight weeks. The estimator below is already set for Denbighshire.

1 · Measured survey

Mike surveys your home himself — no juniors, no outsourcing. The £60 visit fee comes off your fee when you go ahead.

2 · Existing & proposed drawings

Scaled drawings of your home as it is and as it will be — the documents your planning application stands on.

3 · Planning application

Prepared, submitted and handled for you — or confirmation you don't need one under Permitted Development, which saves you the council fee entirely.

4 · Building regulation drawings

The technical pack — structure, insulation, fire safety, drainage — that building control approves and your builder prices from.

What extension plans cost.

Mike works to a fixed written fee, agreed before any work begins. Council fees are separate and paid directly — never through Mike.

ItemTypical costPaid to
Mike’s fee — single storey extension£750 – £1,400Mike (fixed, written)
Mike’s fee — two storey extension£950 – £1,800Mike (fixed, written)
Planning application (if required)£585 Wales / £548 CheshireYour council
Planning Portal service charge£91Planning Portal
Building control (approx.)£600 – £1,000Council / inspector

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Instant Estimate

What might the design & approvals stage cost?

Mike's fee plus the council fees for planning and building control — the full professional stage, before a builder is involved. No forms, no email, no obligation.

1 · Your project
2 · Your council
3 · Do you need planning permission?
Mike's design fee Mike's fee£750 – £1,400
What's included — and why the range?

Mike's fee covers the complete professional package:

  • ✓ Measured survey of your home
  • ✓ Existing & proposed drawings
  • ✓ Planning application — prepared, submitted and handled (if needed)
  • ✓ Full building regulation drawings your builder prices from

Why the range? Every home is different. The lower end covers a straightforward project — a simple survey, standard drawings, no planning application needed. The higher end covers larger or more complex work — a full planning application, more detailed drawings, or structural design to coordinate.

Before any work begins, Mike gives you a detailed written fee proposal — so you know exactly what you're paying and what it covers. The number you agree is the number you pay.

Initial site visit Mike's fee£60 — deducted if you go ahead
How the £60 site visit works

The visit. Mike comes to your home, assesses your space and your plans, tells you whether you need planning permission, and gives you honest advice on what's possible and what it's likely to cost. The visit fee is £60.

Commission the work and it's free. If you go ahead, the full £60 is deducted from your agreed fee — so the visit effectively costs you nothing.

Work beyond the agreed scope. Anything over and above the written fee proposal — amendments after approval, planning appeals, project management — is charged separately at £60 per hour, always agreed with you first.

Planning application Council fee — not Mike's£585
What is this — and how do I pay it?

What it is. The fee your council charges to process a householder planning application — their planners assess your proposed extension against local and national planning policy before granting permission.

Why it's needed. Larger extensions, or ones outside the Permitted Development rules, legally need planning permission before work starts. Many smaller extensions don't need it at all — Mike will tell you which side you're on at your site visit.

How you pay. Paid directly to your council when the application is submitted — it never passes through Mike. The fee is set nationally: £585 in Wales (Flintshire, Denbighshire and Wrexham) and £548 in Cheshire West & Chester. Mike prepares, submits and handles the whole application as part of his fee. Applications go in online via the Planning Portal, which adds a £91 service charge on top of the council fee.

Planning Portal service charge Portal fee — not Mike's£91
What is the Planning Portal?

What it is. The Planning Portal is the official national website where planning applications are submitted online to councils across England and Wales — it's how applications reach your council's planning department.

Why the charge. The Portal charges a flat £91 service fee for processing each application and passing it (and your council fee) on to the council. It applies across the board, whichever council you're in.

How you pay. Paid online at the point of submission, together with the council's planning fee. Mike prepares and submits the application through the Portal on your behalf — this charge just doesn't apply at all if your project is Permitted Development, because there's no application to submit.

Building control Council fee — not Mike's (approx.)£600 – £950
What is this — and how do I pay it?

What it is. Completely separate from planning — building control checks that the construction itself meets the Building Regulations: structure, insulation, fire safety, drainage. An inspector approves the technical drawings and visits the build at key stages.

Why it's needed. It's a legal requirement for extensions and conversions, even when no planning permission is needed. At the end you receive a completion certificate — which you'll need when you come to sell the house.

How you pay. Paid directly to the council's building control team or a private approved inspector — typically a plan charge when the drawings go in and an inspection charge when work starts. Charges vary by council and project size, which is why this line is approximate: Mike obtains an exact quote for you once the design is finalised. Not part of Mike's fee.

👆 Make your choices above — your estimate updates instantly
Mike's fee — based on your choices
£750 – £1,400
Estimated total including council & portal fees
£2,026 – £3,026

Guide figures only. The £60 site visit is not added to the total — it comes off Mike's fee when you commission the work. Council fees correct at July 2026; building control charges vary by council and project — full details in the FAQs. Mike confirms everything in a written fee proposal before any work begins — and he'll tell you at your site visit whether your project qualifies as Permitted Development.

Book your £60 site visit — get a written fee proposal

Questions people ask.

Do you cover the Denbighshire coast as well as the vale?

Yes — Prestatyn, Rhyl and Rhuddlan on the coast, St Asaph and Bodelwyddan in the middle, Denbigh and Ruthin in the vale, and the villages between. Under an hour from Deeside to all of it.

My cottage is old and thick-walled — can it still be extended?

Almost always, with a design that respects how the building works — older solid-wall properties need particular care with junctions, damp and materials, which is exactly where 25 years of drawing experience pays for itself. If the building is listed, Mike will advise on listed building consent alongside planning.

How much does planning permission cost in Denbighshire?

The Wales-wide householder fee: £585 to the council plus £91 to the Planning Portal, only when permission is actually needed — many extensions proceed under Permitted Development, which Mike confirms before any fees are committed.

Start with a number, not a commitment.

Three taps on the estimator gives you a realistic figure. When you're ready, the £60 site visit comes off your fee if you go ahead.

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