Most people treat this as a question of budget and taste. It usually isn't. It is decided by the staircase — because building regulations set a minimum head height over it, rooflights add no height whatsoever, and on a hipped roof there is often nowhere the stair can land without one.
↓ Why the staircase decides it 📋 Book the £60 Initial Site Appraisal MeetingEvery loft conversion runs into this sequence, and it runs in one direction only. Most people meet it backwards — they choose rooflights to avoid a planning application, then discover the stair does not comply.
A loft only counts as habitable if it meets the building regulations. That is what makes it a bedroom on a floorplan rather than an attic with a carpet.
A fixed staircase, at a legal pitch, with legal headroom over it. This is not negotiable and it is not something a builder can sign off himself.
2m over the stair as standard. A loft conversion may reduce that to 1.9m at the centre of the stair and 1.8m at the side — and no further.
Hipped roofs slope on all four sides, so the full-height band is narrow and both ends are lost. There is frequently nowhere for the stair to land.
A dormer is the only way to create height where there wasn't any. Rooflights follow the existing slope and add nothing at all.
And that is what can take the job out of Permitted Development. The planning question is decided by the staircase, several steps earlier.
The difference is at the ends of the house. A gable roof finishes with a vertical wall built up to a point. A hipped roof has a fourth roof slope there instead — which looks tidier from the street and costs you the most useful part of the loft.
Left: a gable end — a vertical wall to the apex, so the loft keeps its height right to the end of the house. Right: a hipped end — a fourth roof slope, and the height disappears before you reach the wall.
Cut through the roof and the problem is obvious. The band where you actually have standing height is narrower than people expect, and the staircase has to arrive inside it — not just the top step, but the headroom above the whole flight.
Rooflights sit in the plane of the existing roof, so they change nothing on this drawing. Only a dormer moves the line.
| Rooflights only | Dormer | |
|---|---|---|
| Adds head height | None — follows the existing slope | Yes, that is the point of it |
| Adds floor area you can stand in | No | Yes |
| Planning permission | Almost always Permitted Development | Usually PD at the rear or side; never on the road-facing slope |
| Cost | Considerably cheaper | Structural work — a significant part of the build cost |
| Works if head height is already sufficient | Yes — the right choice | Unnecessary expense |
| Works if head height is short at the stair | No, and no design will rescue it | Usually the only option |
This is why "we'll just do rooflights and avoid the planning application" is a decision that cannot be made before somebody has measured. Sometimes it is exactly right and saves you thousands. Sometimes it produces a loft that cannot legally be a bedroom.
When head height is short, the reflex is to look for a smaller staircase — an alternating tread or "paddle" stair. It is worth knowing the rules before pinning hopes on it, because they run the opposite way to what people assume.
Approved Document K requires the full 2m over an alternating tread stair — more than the 1.9m reduced allowance a conventional loft stair is given. If you are short on height, it makes the problem worse.
It is permitted as a last resort, not a design choice, and building control will expect to see why a conventional staircase was not possible.
An alternating tread stair may serve just one habitable room, plus an optional bathroom or WC. A two-bedroom loft is out.
If the measurements say rooflights will do, you may well be in Permitted Development — no application, no council fee and no eight-week wait — provided the house is outside protected land and the rooflights stay within the limits. If they say you need a dormer, the dormer is usually still Permitted Development at the rear or the side — within the volume allowance, set back from the eaves, and no higher than the existing ridge. On the roof slope facing the road, it is not.
What none of that survives is a guess. The whole chain rests on a measurement taken where the staircase has to land.
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.
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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.
Or have Mike email this estimate to you — no obligation.
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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.
2m as standard. Approved Document K allows a reduction for loft conversions where space is tight: 1.9m at the centre of the stair width, reducing to 1.8m at the side. Below that it does not comply.
Usually yes, but it more often needs a dormer, a hip-to-gable, or both. The hip removes height at the ends of the house, which is frequently where the staircase has to come up. It is the commonest reason a conversion that "obviously" only needed rooflights turns out to need more.
Rebuilding the hipped end as a vertical gable wall, so the loft keeps its full height to the end of the house. It suits semis and detached houses with hipped roofs and is often paired with a rear dormer for the biggest gain.
Only if the head height is already there. Rooflights sit in the plane of the existing roof and add no height at all. If the stair cannot achieve its headroom, rooflights do not change that.
Someone measures it. Ridge height, the position of the existing stairwell, the roof structure and where a new stair could land. That is what the £60 Initial Site Appraisal Meeting settles, and it comes off Mike's fee if you go ahead.
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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