Sometimes you may not need it — a loft conversion can be Permitted Development. But “sometimes” is not “yours”, and a few things take that right away. Here is how to check before you spend anything — and, just as importantly, what actually happens if the answer turns out to be yes.
↓ What takes it away ↓ What if I do need permission?Many loft conversions do not need planning permission. They fall under Permitted Development — a national right that lets you enlarge your roof without applying to the council, as long as you stay inside a set of limits. Two of those limits do most of the work:
The most additional roof space you can add to a terraced house without planning permission. Same figure in Wales and England.
The allowance for a detached or semi-detached house. Again, identical either side of the border.
To put 40m³ in real terms: a rear box dormer about 4 metres wide, 2.5 metres deep and 2.3 metres high is roughly 23m³. Most single rear dormers sit comfortably inside the allowance.
The catch most people miss: the allowance is cumulative. Any earlier enlargement of the roof counts against it — including work done by a previous owner, decades ago, that you know nothing about. If the loft has been touched before, the remaining allowance may be far smaller than you think.
A few things remove the right — the type of house, where it is, what has already been built, and what the dormer would look like from the road. Mike checks them on the visit, before you spend anything.
Needing planning permission is not a refusal, and it is not the end of the project. It is a form, a fee and a wait. It is worth knowing exactly what changes — and what doesn’t — before you let it put you off.
Your council has eight weeks to determine a householder application. Some come back faster — several of Mike’s Hawarden applications were decided inside five weeks. Plan for a couple of months between submission and decision, running alongside the rest of your preparation rather than holding it up.
The council fee — £585 in Wales, £548 in Chester and Wirral — plus the £149 Planning Portal charge. Both go directly to them, never through Mike.
Needing permission rarely means redesigning the loft you wanted. In a conservation area the conversation is about appearance — materials, window style, dormer proportions — not about whether you can convert at all.
Preparing the application, submitting it and answering the council’s questions is part of what Mike does, quoted in the fixed written fee agreed before anything starts. No surprise invoice when a planning officer picks up the phone.
And the part worth hearing before you worry: if Mike thinks an application is likely to be refused, he tells you at the Initial Site Appraisal Meeting — before you have paid a council fee or committed to drawings. Every application he submits goes onto the council’s public register with its decision attached — 165 of them to Flintshire since 2010, and that is only the applications: the projects that qualified as Permitted Development needed none and left no trace. You can read every decision yourself, including the ones that went against him.
Search the planning register — Agent: Deeside Architectural →
This is the single most expensive misunderstanding in loft conversions. Permitted Development removes the need for planning permission. It does nothing about building regulations — and every loft conversion needs building regulations approval, without exception.
Building control looks at the things that make a loft safe to sleep in: floor structure and steel sizing, the staircase and how it lands, fire doors and a protected escape route, insulation, ventilation and glazing. A loft converted without it is not a bedroom — it is a boarded attic, and it will be described that way when you come to sell.
So the honest sequence is: establish whether you need planning permission, then get the building regulation drawings either way. The second part is never optional.
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 design and approvals stage:
Why the range? Every home is different. The lower end covers a straightforward project — 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 are paying and what it covers. The number you agree is the number you pay.
Only if planning permission is needed. Wales charges £585 for a householder application and Cheshire West & Chester £548 — the fee is set nationally, so it does not vary between Welsh councils. Paid directly to your council, never through Mike.
The service charge for submitting a planning application online. It also only applies if permission is needed, and it is charged per application submitted.
This one always applies, permission or not. It is calculated on floor area and subject to the final design — smaller projects sit toward the lower figure, larger ones toward the higher. Paid to the council's building control team or a private approved inspector, never through Mike, and he gets you an exact quote once the design is finalised.
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, you will not need to pay the council planning fee or the Planning Portal charge, a saving of up to approximately £734. Mike checks this at the Initial Site Appraisal Meeting.
Read more about extension plans →
Already built it without approval? Regularisation →
Guide figures only. The £60 Initial Site Appraisal Meeting is not added to these figures — 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.
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£60, and it comes off your fee when you go ahead. Mike comes to the property to understand the scope of what you want to do and advise you accordingly — then sends a written fixed fee afterwards.
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.
Sometimes you may not need it. Some loft conversions in Wales and England are Permitted Development. The new roof space must stay under 40m³ on a terraced house or 50m³ on a detached or semi, must not go higher than the existing roof, and must not break the roof slope facing the road. Permitted Development is removed entirely in conservation areas and on other designated land, and does not apply to flats or maisonettes.
40m³ of additional roof space on a terraced house, 50m³ on a detached or semi-detached house — the same figures in Wales and England. The allowance is cumulative, so any earlier roof enlargement counts against it, including work by a previous owner. A typical rear box dormer of about 4m × 2.5m × 2.3m is roughly 23m³.
A rear or side dormer is normally Permitted Development if it stays inside the volume allowance and sits at least 20cm back from the original eaves. A dormer on the front roof slope (the principal elevation) is not Permitted Development and needs a planning application.
Rarely. Rooflights add no volume, so a rooflight-only conversion is almost always Permitted Development, provided the windows do not project more than 150mm beyond the roof plane and do not sit above the highest part of the roof. Conservation areas and listed buildings are the exception.
Yes, but it needs planning permission. In Wales, roof extensions are not Permitted Development in conservation areas, National Parks, AONBs or World Heritage Sites, and England applies the same rule on designated land. The conversion is still possible — it just goes through an application first, and the design will need to be sympathetic.
Yes, always. Permitted Development only removes the planning application. Building regulations approval is separate and covers structure, stairs, fire escape, insulation and ventilation. No loft conversion is exempt.
Your council has eight weeks to decide a householder application. You pay the council fee — £585 in Wales, £548 in Chester and Wirral — plus the £149 Planning Portal charge, both directly to them. Mike prepares, submits and handles the application as part of the fixed fee agreed at the start. The design itself usually does not need to change; in a conservation area the discussion is about materials and appearance rather than whether you can convert at all.
Not usually, and you will not find out the hard way. If Mike thinks an application is unlikely to succeed he says so at the Initial Site Appraisal Meeting, before you have spent anything on council fees. His decisions are all on the public register — 165 applications to Flintshire since 2010, and that is only the ones that needed permission at all. You are welcome to read them, including the refusals.
Yes — that is what the £60 Initial Site Appraisal Meeting settles, and it is the commonest way people save the council fee. He looks at the loft, checks your property's planning history and designations, and tells you straight whether you need an application. If you go ahead, the £60 comes off his fee. If you would rather talk it through first, the 15-minute call is free.
Two taps on the estimator gives you a realistic figure. When you're ready, the £60 Initial Site Appraisal Meeting comes off your fee if you go ahead.
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