Budgeting a prior approval application under Class MA

The application fee for a Class MA prior approval is a small part of what the exercise costs. The evidence is the expense: a natural light assessment for every habitable room, noise evidence where there is commercial activity nearby, a contamination desk study, flood information where the building sits in Flood Zone 2 or 3, and a drawn scheme that demonstrates compliance with the nationally described space standard. On a small former office, the supporting information routinely costs several times the fee.

Class MA sits in Part 3 of Schedule 2 to the General Permitted Development Order 2015 and allows a building in Commercial, Business and Service use within Class E to become dwellinghouses in Class C3, subject to prior approval. The class has been amended more than once, so work from the consolidated text on legislation.gov.uk rather than from an older summary.

What the application fee covers and what it does not

The prior approval fee is set by the fee regulations, is indexed each April, and differs from the fee for a full planning application. Take the current figure from the Planning Portal fee calculator or the authority's own published schedule on the day you submit, because an out of date figure is a common reason for an application sitting unvalidated while the clock has not started.

The fee buys determination of the specified prior approval matters and nothing else. It does not buy an assessment of design, density, affordable housing or amenity space, because those are outside the matters the authority may consider. That constraint cuts both ways: the authority cannot refuse on design grounds, and it cannot approve a scheme that fails one of the listed matters because the rest is attractive.

The Community Infrastructure Levy can still bite. Development permitted by a general consent is chargeable where a charging schedule is in place, and the applicant has to serve a notice of chargeable development before work starts. Existing floorspace in lawful use for the required qualifying period can usually be offset, which on a full conversion often reduces the liability to nothing. Check the authority's adopted schedule before assuming either way.

The evidence that qualifies the building

The qualifying conditions are the first place an application fails, and they cost very little to evidence if the records exist.

The building has to have been in a use falling within Class E for a continuous period before the date of application. The evidence that works is documentary: business rates records, a lease or licence with dates, VAT registered invoices showing trading from the address, utility accounts, dated photographs of signage. A statutory declaration on its own is weaker than a rates record.

The conditions attached to the class have changed, including the former floorspace cap and the vacancy requirement, so confirm what currently applies from the consolidated order before you build the evidence pack. Budget an hour of a surveyor's time to assemble it and keep it in one appendix rather than scattered through the forms.

Where the building sits on article 2(3) land, in a conservation area, and the ground floor is in use for a retail or office purpose, the loss of that ground floor use is itself a prior approval matter, which adds a short planning note to the pack.

Natural light, and why it drives the budget

The adequacy of natural light in all habitable rooms is a prior approval matter in its own right, and it is the one that most often turns a low cost conversion into an expensive one. Deep floorplates, single aspect units and light wells are the usual culprits.

A competent assessment models each habitable room against a recognised method and reports room by room rather than as an average. A daylight and sunlight assessment prepared for this purpose has to cover the proposed internal layout, so it cannot be produced until the plans are settled, and it frequently sends the layout back for revision. Budget for two rounds.

Rooms with no window at all are refused. There is no mitigation argument available, because the condition is about the provision of light rather than about reasonable alternatives. Where a unit cannot get a window into a bedroom, redraw the unit.

New openings, light wells and rooflights may themselves need planning permission, since Class MA permits the change of use and limited associated works rather than unlimited external alteration. That second application adds fee, time and sometimes a design argument the prior approval route was meant to avoid.

Noise, contamination, flood and transport evidence

Noise from existing commercial premises on the intended occupiers is assessed where there is a relevant source nearby: a pub, a takeaway with extraction, a workshop, a loading bay, a plant deck. The survey has to run long enough to capture the operating pattern, which for evening uses means night time monitoring. The cost of a survey tracks the monitoring period more than anything else, as set out in the note on budgeting a noise survey and its monitoring period, and a Noise Impact Assessment following BS 4142 and BS 8233 is the usual output.

Contamination is dealt with through a Phase 1 desk study in the first instance. Former industrial, automotive, dry cleaning or fuel storage history on or next to the site pushes it towards intrusive investigation, and a land contamination assessment prepared under BS 10175 by a suitably qualified person is what the authority will expect. Phase 2 costs several times Phase 1, so the desk study is worth doing early enough to inform the purchase price.

Flood risk applies where the building is in Flood Zone 2 or 3 or in an area of surface water risk. For a change of use the assessment concentrates on safe access and egress, finished floor levels, flood resilient construction and a flood warning and evacuation plan, rather than on the sequential test.

Transport impacts are assessed narrowly, mainly around safe site access and servicing. On a small urban conversion a short transport note usually suffices. Parking provision is not a matter the authority can refuse on under this class, which surprises objectors.

Space standards and the drawings behind them

Units created under Class MA have to meet the nationally described space standard. That means minimum gross internal areas by number of bedrooms and bedspaces, minimum bedroom areas and widths, a built in storage allowance and a minimum floor to ceiling height over the specified proportion of the gross internal area.

The drawings therefore have to be measured, not sketched. Budget for a measured survey of the existing building, floor plans at a scale that lets areas be checked, and an area schedule that sets the standard against the proposed figure for every unit. Authorities check the arithmetic.

The ceiling height requirement catches conversions of buildings with suspended ceilings and deep service zones. Stripping the ceiling to gain height then changes the acoustic and fire strategy, which belongs in the construction budget rather than the planning one.

Work that sits outside the planning budget

Prior approval says nothing about whether the building can be converted economically. Separation between dwellings has to meet Approved Document E, which on a concrete framed office is straightforward and on a timber framed building is not. Means of escape, compartmentation and, for taller buildings, the Building Safety Regulator's gateway process all sit under building control.

Services are the other line people forget. Incoming water, electrical capacity, gas, drainage connections and metering for multiple dwellings often need upsizing or diversion, and the lead times set out in the note on budgeting utility connections and diversions can run to months. Find out what each undertaker requires before you own the problem.

The 56 day clock and the cost of refusal

The authority has 56 days from a valid application to determine it, and if it does not, the development may proceed subject to the conditions in the class. That makes validation the moment that matters. An application submitted with a missing form, an unpaid fee or an absent light assessment does not start the clock at all.

If prior approval is refused, the costs already sunk on surveys do not disappear, because most of that evidence supports either a resubmission or an appeal. An appeal against refusal goes to the Planning Inspectorate and carries no appeal fee, though it carries time: on written representations, months rather than weeks.

An illustrative budget for a two storey former office of around 400 square metres might run to a measured survey, architectural drawings, a natural light assessment, a Phase 1 desk study, a short transport note, a planning covering statement and the application fee. The light assessment and the drawings together usually account for more than half of it. Figures vary by location and building, so price the work rather than relying on a range.

See PlanScope pricing if you want the written planning statement drafted and reviewed rather than written from scratch. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it.