Co-working conversion of an office floor
Doubling the population of an office floor does not change its use class. It changes cycle demand, ventilation rates, sanitary provision and escape capacity.
Fitting out an office floor as co-working space almost never needs planning permission for the change of use. It stays within Class E(g)(i), and movement within a use class is not development. What changes is the number of people on the floor, and the questions that follow are about density rather than class: cycle parking, sanitary provision, ventilation rates, escape capacity and whether an old condition on the building still bites.
A conventional office floor is often planned around one person per 10 square metres. Co-working operators routinely work at half that. Doubling the population of a floor does not change its use class and it does change almost everything else.
Why co-working stays inside Class E(g)
Class E(g) covers uses which can be carried out in a residential area without detriment to amenity: offices to carry out operational or administrative functions, research and development, and light industrial processes.
A co-working operator running desks, meeting rooms and a members lounge is carrying out office functions. The fact that the occupiers are many small businesses rather than one tenant is a matter of tenure, not of planning. Tenure is not a use class question, and a council asking for an application on the basis that the occupier has changed is asking for something the legislation does not require.
That answer holds for serviced offices, managed workspace, incubators and hot-desking. The detail that matters is what else is on the floor, which the ancillary section below deals with.
Intensification and when it becomes a material change
Intensification of an existing use can amount to a material change of use, but only where the intensification changes the character of the use rather than simply its scale. That is a high bar and it is rarely crossed by an office floor taking more desks.
The question a council should be asking is whether the off-site effects change in kind, not merely in degree. Two or three situations get close.
Where the building's parking provision is fixed by a condition and the occupancy now generates demand the site cannot hold, producing overspill into surrounding streets. Where servicing and deliveries change character, for example a members cafe generating daily refrigerated deliveries at a loading bay designed for occasional office supplies. Where evening and weekend use becomes routine in a building previously used only in office hours, in a location with residential neighbours.
None of those is automatically a material change of use. Each is a reason to expect scrutiny, and a reason to have a short Transport Statement available setting out the trip generation at the proposed density and the mode share the location supports. The related analysis of co-working space in a former office building covers the building-level questions that sit alongside this.
Old conditions that still refer to B1(a)
This is the trap that catches most schemes, and it has nothing to do with the 2020 use class reforms in themselves.
Many permissions granted before September 2020 carry a condition restricting the use of the building to Class B1(a) offices, or restricting hours, occupancy or parking. Those conditions continue to have effect and are construed by reference to the classes as they stood when the permission was granted. Class E flexibility does not override an express condition.
So a building with a condition limiting the use to offices within the old B1(a) cannot become a gym or a nursery without an application, even though both are now in Class E. And a condition limiting occupancy to a stated number of staff, or restricting the use of car parking spaces, bites on a co-working operator exactly as it did on the previous tenant.
Read the decision notices for the building before signing a lease. Where a condition is obstructive, an application under section 73 of the Town and Country Planning Act 1990 to vary it is usually the right route, and it is a far quicker conversation than a retrospective enforcement discussion.
Cycle parking, showers and end of trip facilities
Higher occupancy raises cycle demand proportionately, and cycle parking standards in most local plans are expressed per square metre or per employee.
Where the fit-out is internal only, there is no planning trigger. Where a cycle store is being built in the forecourt, converted from part of the car park, or added to the elevation, that is operational development and needs permission.
Plan the end of trip provision as a package: secure long stay cycle parking at ground or basement level with step-free access, short stay stands for visitors within sight of the entrance, showers and lockers scaled to the cycling mode share you expect rather than to a minimum standard, and drying space. In London the plan-level standards are set out in the London Plan, and boroughs apply them to changes of use and material intensification.
One practical point. Converting car parking spaces to cycle parking often needs permission where the parking was required by condition, and it is usually granted readily, but it is not automatic.
Ventilation, sanitary provision and escape at the new density
These are building control matters rather than planning ones, and they are the constraints that actually limit how far the density can go.
| Issue | What changes at higher density |
|---|---|
| Mechanical ventilation | Fresh air rates are per person, so doubling occupancy doubles the required supply and may exceed the existing plant |
| Sanitary provision | Numbers of WCs and washbasins are set by occupancy under workplace welfare requirements and the relevant standard |
| Toilet accommodation layout | Newer requirements in England govern the provision of separate or universal toilets in non-domestic buildings |
| Means of escape | Escape route widths, exit capacity and travel distances are calculated from the design occupancy |
| Cooling and overheating | Occupant heat gains rise with density, often the binding constraint in a glazed floorplate |
Establish the existing plant capacity before agreeing a desk count with the operator. Where the air handling unit cannot serve the proposed occupancy, the options are additional plant, which may be external and therefore development, or a lower density. New rooftop plant brings its own noise assessment, and a Noise Impact Assessment under BS 4142 is normally expected where residential receptors are nearby.
Escape capacity is the hard stop. If the stair cannot take the occupancy, no amount of fit-out design fixes it.
Cafes, events and the ancillary line
A coffee counter serving members is ancillary to the office use and raises no separate question. Two things move it.
Opening the cafe to the public. That is still within Class E, since the sale of food and drink for consumption on the premises sits in Class E(b), so no change of use permission is needed unless a condition restricts it. But extract for any cooking beyond reheating is operational development, and a Ventilation and Extraction Statement covering the flue route, termination and odour control will be expected where a duct appears on the elevation.
Running events. Regular evening events with amplified sound, ticketed entry and attendance well beyond the membership can take the use outside Class E altogether and towards a sui generis venue. Occasional member events do not. The line is drawn by frequency, scale and whether the public are admitted, and it is a question of fact and degree rather than a threshold.
Where events are part of the business model, record what is proposed in writing and consider a certificate rather than waiting for a complaint about noise at 10pm.
When an application is still needed
Five triggers, and they are all about the building rather than the use.
- Any external alteration: plant, extract ducts, cycle stores, entrance alterations, terraces or signage beyond what advertisement regulations permit.
- Any condition on an existing permission restricting use, hours, occupancy or parking, which needs a section 73 application to vary.
- An Article 4 direction removing permitted development rights in the area.
- A listed building, where internal alterations can require listed building consent regardless of the use.
- A change that takes part of the floor outside Class E, such as a residential element or a venue use.
Where none of those applies, the honest answer is that a co-working fit-out is a building control and licensing exercise rather than a planning one. That is worth saying plainly to a landlord who has been told otherwise.
Enter your postcode on PlanScope to see which reports a change to an office building is likely to need.
This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
Does a co-working space need planning permission?
Usually not for the use itself. Co-working, serviced offices and managed workspace all sit within Class E(g)(i), and movement within a use class is not development. Tenure is not a planning question. Permission is needed for external alterations, to vary a restrictive condition, or where an Article 4 direction or listed status applies.
Can intensification amount to a material change of use?
It can, but only where the intensification changes the character of the use rather than its scale alone. That is a high bar. The relevant question is whether off-site effects change in kind: parking overspill beyond the site, servicing of a different character, or routine evening and weekend use in a previously office-hours building.
Does a condition referring to Class B1(a) still apply?
Yes. Conditions on permissions granted before September 2020 continue to have effect and are construed by reference to the classes as they stood when the permission was granted. Class E flexibility does not override an express condition, so a building restricted to B1(a) offices still cannot become a gym without an application.
What limits how many desks a floor can take?
Building control usually, not planning. Fresh air supply rates are calculated per person, sanitary provision is set by occupancy, and escape route widths and travel distances are calculated from the design occupancy. Escape capacity is the hard stop, because no fit-out design fixes a stair that cannot take the numbers.
Can the members cafe be opened to the public?
In use class terms usually yes, because the sale of food and drink for consumption on the premises sits in Class E(b) and the building is already Class E. Check for a condition restricting it. Any cooking beyond reheating will need extract, and a duct on the elevation is operational development requiring permission.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.