Which reports Class MA office to flats prior approval needs

Class MA prior approval is not a mini planning application. The council can only refuse it on the matters the Order lists, and everything else, including whether the town needs more flats and whether the design is any good, is outside its remit. The matters are transport and site access, contamination, flooding, noise from commercial premises affecting the future residents, the loss of a ground-floor use in a conservation area, the effect of introducing housing into an area important for industry or storage, and, for taller buildings, fire safety. Add to those the condition requiring adequate natural light in every habitable room.

Evidence each one properly and the application is difficult to refuse. Assert them and it is straightforward to refuse.

The eligibility conditions before you reach the matters

Prior approval only becomes relevant once the building qualifies. Check these first, because a refusal on eligibility is a wasted fee and a wasted 56 days.

• The building must have been in Class E use, and must have been in that use, for a continuous period of at least two years before the date of the application.
• The building must not be listed, within the curtilage of a listed building, or a scheduled monument.
• The site must not be occupied under an agricultural tenancy, and various other exclusions in the Order apply.
• Article 4 directions remove Class MA in a growing number of town centres, so check the council's Article 4 register for the specific street.

The Order was amended with effect from 5 March 2024, removing the 1,500 square metre floorspace limit and the requirement that the building be vacant for three months before the application. Read the current consolidated text rather than an older summary, because the conditions have moved more than once since Class MA was introduced in 2021.

Development must be completed within three years of prior approval, which is tighter than the standard implementation period for a full permission.

Noise from commercial premises

This is the matter that produces the most refusals, and it is a peculiar one because it is assessed the other way round from an ordinary noise case. The question is not whether the new residents will disturb the neighbours. It is whether the existing commercial uses will disturb the new residents.

What the officer wants to see in a Noise Impact Assessment is straightforward.

1. Identification of every commercial noise source within influencing distance: plant on adjoining roofs, a delivery yard, a bar, a takeaway extract fan, a gym, servicing to the rear.
2. Measured sound levels at the proposed facades over a period covering the hours those sources operate, including night-time where relevant.
3. An assessment of internal levels in habitable rooms against BS 8233:2014 guideline values, with the glazing and ventilation specification that achieves them.
4. Consideration of whether the ventilation strategy still works with windows closed, since acoustic performance that depends on sealed windows needs mechanical ventilation to be credible.
5. Where plant is the dominant source, a BS 4142:2014+A1:2019 assessment of that plant.

The trap is proposing mitigation that solves the noise and creates an overheating problem. Councils have become alert to sealed flats with no cooling strategy, and a scheme that relies on closed windows should show how summer temperatures are managed.

Councils expect a suitably qualified acoustician for this work, and professional review is strongly advised.

Contamination, flooding and transport

These three are usually lighter, but each has a way of going wrong.

Contamination is assessed in relation to the building. For a 1970s office block the honest answer is often that the risk is low, but the assessment still has to be made. A Phase 1 desk study reviewing historic maps, the site's industrial history and any made ground is the normal submission, with a Phase 2 intrusive investigation only where the desk study identifies a plausible pollutant linkage. This work must be prepared in accordance with BS 10175 by suitably qualified and experienced persons, and a Land Contamination Assessment drafted in advance is a starting point for that professional rather than a substitute.

Flooding is also assessed in relation to the building. Where the site sits in Flood Zone 2 or 3, submit a Flood Risk Assessment covering finished floor levels of the lowest residential units, safe access and egress, and a flood warning and evacuation plan. Ground-floor flats in Zone 3 are the difficult case, and relocating habitable accommodation to upper floors with commercial or plant at ground level is often the answer.

Transport is limited to transport and highways impacts, particularly ensuring safe site access. A short Transport Statement covering the access arrangement, refuse collection, cycle parking and any change in vehicle movements is normally proportionate. Note that the council cannot refuse because the scheme provides no car parking, since parking provision is not one of the listed matters, though safe access is.

Natural light and space standards

Every habitable room must have adequate natural light. This is the requirement that most often forces a redesign of a deep-plan office floorplate.

There is no numeric threshold in the Order, so councils apply judgement informed by daylight modelling. A daylight assessment reporting average daylight factor or the metrics in the current daylight standard, room by room, with the room use labelled, is the way to answer it. Rooms with no window at all will fail. Bedrooms served only by a light well need modelling rather than assertion.

The nationally described space standard applies to new dwellings created under Part 3, so floor areas, storage provision and bedroom dimensions have to meet it. Set out a schedule of accommodation showing the gross internal area of each unit against the standard for its bedroom and bedspace count, and flag any shortfall openly rather than leaving it to be discovered.

An illustrative submission pack for eight flats

Illustrative example. A three-storey 1970s office building in a town centre outside a conservation area, no Article 4 direction, Flood Zone 1, with a nightclub two doors away and a small delivery yard to the rear, converting to eight flats.

• Prior approval application form under Class MA, with the fee calculated per dwelling.
• Existing and proposed floor plans and elevations, and a schedule of accommodation against the space standard.
• Evidence of two years of Class E use: business rates records, leases, filed accounts.
• Noise assessment covering the nightclub, the delivery yard and rooftop plant, with the glazing and ventilation specification.
• Daylight assessment reporting each habitable room.
• Phase 1 contamination desk study.
• Transport statement covering access, refuse and cycle storage.
• A short covering statement addressing each prior approval matter in turn, under its own heading.

That last item is worth the hour it takes. Officers determining prior approvals work to a 56-day deadline and appreciate a document structured to the matters they must consider.

When a full application beats prior approval

Prior approval is faster and narrower. That is not always an advantage.

Consider a full application where the scheme needs external alterations beyond what Class MA permits, since the class covers the change of use and limited associated building operations only. Consider it where the building is listed or in a conservation area and the ground-floor loss is contentious. Consider it where the unit mix or the size of the units would fail the space standard, because a full application allows a design conversation rather than a binary refusal.

And consider it where you want to increase the floorspace, add storeys or reconfigure the envelope, since those go beyond the class entirely and would need separate consents anyway.

Where the building is straightforward, in Class E use for years, in a decent location, with daylight on three elevations, prior approval is the better route and the 56-day period is worth having.

Enter your postcode on PlanScope to see which reports a conversion site is likely to need. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval, and for specialist technical reports qualified professional input may be required. This is general guidance rather than legal advice.