Measured survey, planning application and full building regulation drawings for single and two storey extensions — across Deeside, Flintshire, Chester, Wrexham and Denbighshire. One fixed written fee, from £750.
⚡ Get an instant estimate 📋 Book a £60 site visit ⓘ Why a site visit?An extension lives or dies on its drawings. They decide whether the council says yes, whether your builder can quote accurately, and whether the build matches what you imagined. Mike Williams has produced extension drawings across North Wales and the border for 25 years — established 2010, registered at Companies House, every application publicly checkable on the council planning portals.
Mike surveys your home himself — no juniors, no outsourcing. The £60 visit fee comes off your fee when you go ahead.
Scaled drawings of your home as it is and as it will be — the documents your planning application stands on.
Prepared, submitted and handled for you — or confirmation you don't need one under Permitted Development, which saves you the council fee entirely.
The technical pack — structure, insulation, fire safety, drainage — that building control approves and your builder prices from.
Mike works to a fixed written fee, agreed before any work begins. Council fees are separate and paid directly — never through Mike.
| Item | Typical cost | Paid to |
|---|---|---|
| Mike's fee — single storey extension | £750 – £1,400 | Mike (fixed, written) |
| Mike's fee — two storey extension | £950 – £1,800 | Mike (fixed, written) |
| Planning application (if required) | £585 Wales / £548 Cheshire | Your council |
| Planning Portal service charge | £149 | Planning Portal |
| Building control (approx.) | £600 – £1,000 | Council / inspector |
Or just use it right here ↓
Mike's fee plus the council fees for planning and building control — the full professional stage, before a builder is involved. Two taps for a figure — no obligation.
Mike's fee covers the complete professional package:
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.
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.
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 £149 service charge for a householder application on top of the council fee.
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 Planning Portal is the official route applications take to your council, and it charges a service fee on any application whose council fee is over £100. Since 2026 that fee is banded by application type: Band 1 is £99 inc VAT and Band 2 is £149 inc VAT. A householder application to enlarge, improve or alter an existing dwelling — which is what an extension, loft or garage conversion is — sits in Band 2, so £149. It is charged per application submitted, so a project that goes to outline permission first and reserved matters afterwards pays it twice. You can check any application type against the Planning Portal’s published bands.
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.
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.
Design and approvals only. This is what it costs to get your project drawn and approved — it does not include your builder’s costs for the actual building work.
If your project turns out to be Permitted Development, up to £734 of this comes off — Mike checks for free at your site visit.
Read more about extension plans →
Already built it without approval? Regularisation →
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.
Or have Mike email this estimate to you — no obligation.
✅ Sent — your estimate is on its way. No obligation.
Couldn't send just now — call Mike on 07703 786 460 or email [email protected].
Every planning application Deeside Architectural Design submits goes onto the council's public register — under the practice name, with the decision attached, permanently. It's free to search and it isn't curated by us. What the register cannot show you is the other half of the work: the projects that qualified as Permitted Development, needed no application at all, and saved the client the council fee. Those leave no public trace. So the number below is the part you can check — not the whole of it. Before you decide whether the fee above is worth paying, go and read it.
Submitted to Flintshire County Council under Deeside Architectural Design since 2010 — every one searchable, with its decision attached.
Many projects qualify as Permitted Development, need no application, and never reach the register. The 165 is the work that required permission — not the count of jobs done.
Deeside Architectural Design Limited, incorporated January 2010, and 25 years of drawings behind it. Companies House no. 07128221.
Open Flintshire's planning register, put Deeside Architectural in the Agent field, and read every decision — including the ones that didn't go our way.
Search Flintshire's planning register →
Figures taken from Flintshire County Council's public planning register, August 2026.
Everything above is about work you are planning. There is a second situation Mike handles, and it catches people out years later: an extension that was built without building regulations approval. It sits there causing nobody any trouble — until you come to sell. Then the buyer's solicitor asks for the certificate, there isn't one, and the sale stops dead.
It is fixable, and it is a different job from the one priced above. Mike acts as your consultant through regularisation: the site visit, the drawings and statements building control need, the meeting with the building control officer at the property, and the coordination on any work required before the certificate can be issued. From £997 to £1,500, depending on what was built and what it takes to satisfy the council.
If there is any chance the extension at your property was never signed off, deal with it now rather than at the point of sale, when you have no time and no leverage.
Often not — many single storey rear extensions fall under Permitted Development (up to 4m for detached homes, 3m otherwise, subject to conditions). Mike tells you which side you're on at the site visit, before any fees are committed. If permission is needed, he handles the whole application.
Survey to submitted application is typically 2–4 weeks depending on complexity. Councils then take around 8 weeks to determine a householder application. Building regulation drawings usually follow while planning is being decided, so no time is wasted.
If you need more than one extra room, two storey almost always wins on cost per square metre — the foundations and roof are being built either way. If the goal is a bigger kitchen or open-plan living, a well-designed single storey can be transformational. Mike will talk you through both honestly at the site visit.
Yes — they're the same building-regulation-standard drawings every builder and building control body works from. Good builders prefer them: a fixed scope protects their quote as much as your budget.
Two 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.
⚡ Instant estimate Book the site visit