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How to convert offices into homes without planning permission [2023 update]

Do you have offices that you want to convert to flats? Here's how to use your Class MA permitted development rights while creating great places to live

6 February 2023
5 minutes read
Convert Offices into Homes without Planning Permission

Simple question: can you really convert offices to homes in England without needing planning permission?

Simple (and to some people surprising answer): in most places and in many cases, yes.

Whether that is a good thing, a bad thing, or something that can be either depending on the circumstances, we’ll leave it to you to decide.

But the fact is that there is a permitted development right that allows you to do office-to-residential conversions, so we’re going to explain why it exists, the troubled history of this type of development, how the new rules for doing this work and then give an example of how to do it well.

Let’s get started…

Why is there a prior approval right for office-to-resi conversions?

There are two ideas underlying the existence of this right, which falls into the category of permitted development known as prior approval.

The first is that the slow and sometimes difficult process of getting planning permission is one of the causes of the housing shortage.

The second, one we’re more inclined to agree with, is that reusing existing buildings is a good idea.

And since 2013, when the original Class O – converting B1(a) (offices) to C3 (house or flat) – right was brought in, there has been a shift in the way that many people doing desk jobs work. That shift was accelerated by the COVID-19 pandemic.

People who would traditionally have commuted into an office are increasingly working from home some or all of the time. That has left some office buildings, especially older ones, struggling to get tenants.

Meanwhile, soaring house prices have meant that residential development has become appealing to property owners who were previously focused on the business market.

All of that seems sensible enough. Unfortunately, when Class O was being drawn up, the government’s priority seems to have been to make it as simple to use as possible. And some of the results of that were, well, terrible.

Future slums

As originally written, Class O lacked provisions to protect the quality of life of the residents of the new flats. And some developers took full advantage, creating cramped and dark “homes”, the worst of which had no windows.

We can only assume that the government was relying on the free market – the idea being that if no one wanted to live in these dark rabbit hutches, the developers would have to change tack. But the housing shortage meant that people had little choice and ended up living in these buildings in awful conditions.

Eventually, the scandal reached a point where the government took action. But it took a very long time, with the requirement for all homes created using permitted development to have natural light only coming in 2020 and national space standards applying to these homes from April 2021.

In the meantime, thousands of flats were created that are frankly unfit for living in.

B1(a), the use class for offices, was merged into Class E. In turn, Class O has given way to Class MA, which covers offices along with all the other uses now grouped under Class E, including shops, restaurants and gyms.

So how does it work in practice?

How do I make a prior approval application to convert offices into residential?

The first thing you need to know is that the property has to have been vacant for three months before the date on which you submit your application.

Secondly, it needs to have been used for one of the uses covered by Class E for at least two years. These include anything that was covered by B1(a) - which was the main category for offices - but also A2 (Financial and Professional Services), which covered estates agents, employment agencies and other types of services that use shopfront locations.

You can’t use Class MA in a National Park, the Broads, an Area of Outstanding Natural Beauty, a Site of Special Scientific Interest, a World Heritage Site, or for a listed building. However, you can use it in a conservation area.

And – this is the big change between the old Class O, which had no size limit, and Class MA – you can only convert 1,500 sqm. But you should know that there is no requirement for you to convert the whole of a building, so you can change the use of several floors of a larger office block.

Before you start the works for converting your office units into residential units, you need to make a prior approval application. Your application should include a full set of drawings and supporting documents relating to the transport and highway impacts, contamination risks, flood risks and noise.

If your property complies with the prior approval mechanism, your council cannot apply any other planning policies in determining the prior approval application. If you tick all the boxes, they have to say yes.

Once you submit your prior approval application to the council, they then have 56 days to make a decision. Once you get approval, you'll be ready to start work on your offices into residential flats development.

What are Article 4 directions?

At the start of this article, we said you could use this right most of the time in most places. Some of the places you can’t are the very protected parts of the country listed above – National Parks etc. But there are also parts of towns and cities covered by Article 4 directions.

Article 4 directions happen at a local level and remove certain permitted development rights, often in particular kinds of places, eg tech clusters or employment centres.

This means that you'll definitely need to apply for planning permission to convert your offices into houses or flats in those instances and it's essential to check with your architectural team or the council if an Article 4 direction applies to your site before launching your project.

But Article 4 directions for Class MA have been the subject of a fierce - and, in October 2022, still ongoing - battle between local councils, especially in London, and the Department for Levelling Up, Housing & Communities. Local authorities have suggested widespread Article 4 directions to block Class MA - originally proposing that almost all of London's Central Activities Zone should be covered. The government has vetoed these blanket Article 4 directions, and requested that councils both select specific streets where they should apply, but also need to justify why those particular areas should be exempted. The message is clear: Class MA must be available in all but a few very sensitive business or retail locations.

This, we anticipate, is a struggle that will continue.

Key factors to take into account

If you are trying to decide whether a building is suitable for office to residential conversion, there are some things you need to consider. And an important fact to keep in mind: this right does not allow you to make any external changes to the building.

Because of that, the first thing you need to assess is windows: every bedroom, living room and kitchen will need to get direct natural light. Think about many office buildings you’ve worked in or visited and you might see the potential problem here.

Let’s be blunt: lack of windows is the deal-breaker for many potential office-to-home conversions.

The second is bins and bikes – since many offices are in town centres, you may well be aiming to get by without providing parking spaces. And offices that aren’t in town probably have a reasonable amount of parking spaces.

But while for most developers bins and bikes are an afterthought, they will need to be stored inside the building. Or at least they will in your Class MA application.

So consider whether the building has existing doors you can get bins and bikes in and out of (because you can’t create new doorways) – and make sure you haven’t worked out the financial viability of your project based on flats you will have to sacrifice for cycle storage.

It’s also worth thinking about fire safety – are there enough staircases to get people out safely?

And again, remember, strictly speaking, you’re not even allowed to create new exit doors, although some councils will be more flexible than others about these matters.

The size limit and the advantage of Class E

As we said, there is a size limit, which means some of the huge conversions done under the old Class O will not be repeatable.

But one thing worth thinking about if you have a building over 1,500 sqm is the flexibility offered by Use Class E. This means you don’t have to end up with an awkward mix of apartments and offices.

You have the freedom to fill the rest of the building with businesses that work well with flats, for instance, cafés, shops and gyms. Not only do you not need planning permission for those changes, you don’t need any planning paperwork at all. (You will need building regulations approval for any structural work on those parts of the building).

Office to residential done well: A case study

Our client owned a medium-sized office building (15,000 sq ft) in a town centre.

They wanted to convert it into flats, but they were aiming for quality, not quantity.

Their goal was to convert the office building into 24 self-contained flats with both Art Deco and midcentury modern design principles.

The building had some advantages: a lobby and staircases that were suitable in size for housing and fire-safety compliant.

There was what is known in the trade as a “plant room” – the place where the electrics and other services run from.

There was an indoor parking area that could partly be repurposed for bikes and bins.

And there were decent-sized windows on the two long sides of the building and one of the shorter sides.

That meant that a reasonable number of flats would be possible, although establishing just how many required collaboration with daylight/sunlight specialists to ensure that every future resident would have the light they deserved.

What we delivered were attractive, well-thought-through flats that any of our team would be happy to live in.

We were lucky to be working with a client that appreciated our creative input – they even hired us to design the logo for the development – and who care about the wellbeing of future residents. That is not always the case, sadly.

If you would like us to help you with your office-to-residential conversion, please don’t hesitate to get in touch.

Getting additional planning permission for converting offices into apartments

One thing our clients were clever to realise was this: just because you don’t need planning permission for the change of use from office to residential, it doesn’t mean that you should shun the use of full planning applications altogether.

Let’s make this clear: the main advantage of using this kind of prior approval is not to do with saving time and effort on a full planning application. It’s that you are working with national rules that function mostly on a yes/no basis, with little judgement from the planning officer and no role for local policies.

Once you’ve got your approval and established your right to turn these into homes, it’s worth thinking about whether you can use planning permission to improve the scheme. Although many councils dislike these permitted development rights, it’s their duty to work towards getting the best result for the residents and the community.

Therefore, with the principle of the scheme approved, you should be looking at how you can end up with something better than the limited nature of what’s allowed by Class MA.

In our case, that involved putting in a planning application for landscaping. We wanted to turn the dreary space in front of the building into a pleasant, sheltered patio for the residents, to give them some much-needed outdoor space. (Outdoor space is one of the things not required in permitted development projects).

The council noted:

“The mix of soft and hardscaping within this old town centre location is considered a welcome improvement.”

Even the conservation area officer was impressed, concluding:

“It does not harm the conservation area and is an improvement to the appearance of the area.”

Using the permitted development rights for office-to-residential conversion well

The view of Urbanist Architecture is that Class MA interferes with the duties of councils to be able to create coherent plans for England’s boroughs and counties. On the other hand, we also understand the opportunities it offers to our clients.

Our commitment is to use the permitted development rights to create new homes responsibly. As you can see from the case study, it is possible to do office-to-residential conversions well.

And, again, it’s worth thinking beyond the narrow confines allowed by Class MA: if you’re not converting a whole building, how will you use the rest of it? And once prior approval is secured, do think about how planning applications could turn this from a scheme that meets the rules to one that is an asset to the community.

How Urbanist Architecture can help you

Urbanist Architecture is a London-based RIBA chartered architecture and planning practice with offices in Greenwich and Belgravia.

With a dedicated focus in proven design and planning strategies, and expertise in residential extensions, conversions and new build homes, we help homeowners to create somewhere they enjoy living in and landowners and developers achieve ROI-focused results.

If you would like us to help you with your office-to-residential conversion, please don’t hesitate to get in touch.

Ufuk Bahar, Founder and Managing Director of Urbanist Architecture

Ufuk Bahar

Urbanist Architecture’s founder and managing director, Ufuk Bahar takes personal charge of some of our larger projects, focusing particularly on Green Belt developments, new-build flats and housing and high-end full refurbishments.

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