HMO Planning Drawings 2022 – Can You Use Your Own Drawings To Gain Planning Permission?

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When considering extensions to existing properties, one of the worst mistakes investors can make is to launch straight into a project without doing their homework.

Especially when it comes to houses in multiple occupation (HMOs), so many developers underestimate the amount of planning needed to not only get permission but to end up with a finished project that meets their original specifications.

The reason this often happens is because they fail to understand what sort of HMO planning drawings they are dealing with, and sometimes use a type of drawing not suitable for the stage and complexity of their project. 

The costs and delays of this sort of mistake can be devastating. Incorrect or poor-quality HMO planning drawings might mean the council asking for more documentation and holding up proceedings.

This can be followed by on-site problems in the construction phase, adding up to costly delays and replanning that can hamper an entire project.

As an architect, there’s nothing I find more annoying than seeing a plan fail. Whether it’s due to obstacles in the planning permission process or the measurements not adding up, it’s frustrating to see things go wrong – especially when a little more planning could have avoided the situation.

Today, we’re going to look at 3 types of HMO planning drawings that councils need to see to get a project started – existing, concept and building regulation drawings – and how to go a step further with construction drawings.

I hope if you can take one thing from this article, it’s the importance of thorough planning, and the level of detail you need before you even think about heading onto a building site.

So, let’s dive in and see not only what your council will need before you can lay the first brick of your design, but what you need as well if you want your design to come to life as you expect.

Everything you need to know about HMO Planning Drawings is here!.  

HMO Planning Drawings
Lead Architect Giovanni Patania and Developer Ryan Windsor reviewing HMO Planning Drawings of a 6 Beds HMO in Cambridge


Do you need HMO planning drawings to get planning permission?

What HMO Planning Drawings will the council want to see?

Can you do your own HMO Planning Drawings for planning permission?

What level of detail is required to complete an HMO project?

What can go wrong if I don’t have the right HMO planning drawings?


Do you need HMO planning drawings to get planning permission?

Let’s start with the fundamental question of whether you actually need HMO planning drawings for your project.

The vast majority of the time, the answer to this question is yes. Your council will want to see your HMO planning drawings before it gives you the go ahead to start work.

When it comes to HMOs, the only real exception to this is for a change of use application for a property that has previously been an HMO. 

In this situation, the council will likely want to see evidence of the property’s past, such as HMO licences or tenancy agreements. If this evidence is solid, drawings may not be necessary.

Otherwise, you’ll need drawings, and we certainly never submit a planning application without them here at HMO Architect.

So, that leads to the question of what the council will want to see.

What HMO Planning Drawings will the council want to see? 

Here, it’s important to remember that it’s not just your proposed plans that the council needs to take into consideration, but the existing ones as well.

We’ve known clients to query us on this in the past. After all, why do you need to submit plans of a building that’s already there before you’ve done any work on it?

It’s because councils are very keen on having a firm “before and after” record of what you intend to do. They need to know what the effects of your design will be on the property in its current state.

With that in mind, there are three basic categories of HMO planning drawings the council will want to see at planning stage – existing drawings, concept drawings (sometimes referred to as “proposed” drawings) and maps.

Existing drawings

Your council will want to see measurements of the building in its current state through the Existing Drawings

Concept drawings

Concept drawings are the measurements you propose for the project you have in mind.


An Ordinance Survey map of a 1:1250 scale will be needed, with the site marked in red. This is so that the council can confirm the location of the building.

Can you do your own HMO Planning Drawings for planning permission?

Unless you’re an expert, we don’t recommend it.

You may think you’re saving time and money by doing HMO planning drawings yourself. Still, we’ve seen time and time again that it could easily lead to a whole host of problems and, ironically, associated costly delays in the long run.

Generally, you can’t go too far wrong if you’re working on a rear extension of three metres or less, because this would fall under permitted development (PD) rights.

That said, it’s still good practice to have architects’ drawings to give you more assurance if you’re in any way unsure.

If a rear extension is between three and six metres, it then requires permission from the neighbours on both sides of the property, so once we get into this territory, professional assistance is strongly advised to ensure a speedy and smooth process.

As for dormer extensions, these can get really complex and rather nasty if you don’t get HMO planning drawings from a professional architect.

There are all sorts of issues with parameters and head height that need to be considered. Otherwise, you could have a real mess on your hands.

Also, remember that an HMO project doesn’t begin and end with getting the green light from the council. You might well draw your own plans and get planning approval, but that doesn’t mean your plan is workable in a practical sense when it comes to construction.

So, while you don’t necessarily need architects’ drawings to get planning permission, that’s only the first stage of the process.

For smooth running of the project and optimal efficiency, it’s better to have the professional input of an architect by your side from concept stage through to completion.

What level of detail is required to complete an HMO project?

So, what the council is looking for is one thing, but now we come to the crux of what’s actually required to get your project from an idea to a realisation as quickly and effectively as possible.

There are several stages of HMO planning drawings that can be part of this process. Not all of them are always necessary, but we certainly insist on the first three.

Existing Drawings

As we’ve discussed, you need drawings and measurements of the existing property to start with. This is to give a comparison between what the property is like now and what you hope to convert it into.

With measurements, it’s generally a case of the more the merrier. Basic measurement of the length, width and height of the room may not be sufficient, so bear in mind that an architect’s measurements will be more specific and precise. 

For example, many rooms are not perfect cuboids and might have raised staggered or curved elements.

HMO Planning Drawings - Existing Drawings
Existing Drawings Set for the conversion of a Foster Care Home

Concept Drawings

We’ve also alluded to concept drawings, which in basic terms are a depiction of the plans you have. They too should contain the measurements of your proposed design.

While concept drawings should help you and the assessor of your plan to envisage the project, it can’t be stressed strongly enough that they are NOT sufficient to head onto the site and start work. 

As we’ve seen this done to disastrous effect, we actually now have it in our contract with clients that building work shouldn’t start with a concept drawing alone. If a client insists, we can’t stop them of course, but they proceed at their own risk.

Concept drawings are only designed to obtain planning permission. If you start going ahead with your project with them alone, you’re shooting yourself in the foot.

HMO Planning Drawings - Concept Drawings for a 9 Beds HMO
Concept Drawings Set for the conversion of a Foster Care Home into a 9 Beds HMO

Building regulation drawings

Building regulation drawings are the bare minimum you need to head on site.

They take things up a notch from the concept drawings and include co-ordination with a structural engineer and an acoustic consultant. In some cases, they may include drainage if it’s a necessary consideration.

Following input from parties like the structural engineer and acoustic consultant, measurements may end up being revised. It might turn out, for example, that a thicker floor than expected is needed for acoustic reasons, which will have a consequential effect on the whole design.

That’s why it’s so important not to put any plans into practical progress until you have building regulation drawings at the very least.

Construction drawings

Finally, we come to the advanced level of the HMO Planning Drawings.

Construction drawings are not always necessary, but are recommended for complex projects, and for high-volume HMOs of seven bedrooms or more.

They’re also ideal if the idea of what your HMO should look like is fixed in your mind, and you want to leave nothing to interpretation.

This level of drawing is often offered in conjunction with interior design services, and that’s an approach we take at HMO Architect.

We can improve the co-ordination of the interior of the build and offer a CGI depiction of what the finished project should look like, complete with furniture.

Co-Living HMO
Co-Living HMO project – Saint Helens, UK

What can go wrong if I don’t have the right HMO Planning Drawings?

A real Example:

We’ve known nightmare tales of clients who have planned a four-bedroom en-suite, only to find upon working on the site that their plans only allow for two bedrooms and a cramped, shared bathroom.

One story that stands out was that of a client who went on site with his own concept drawings for a loft conversion, hoping to fit two bedrooms and two en-suites. When he was on site, he quickly realised that he could only fit one bedroom and one en-suite.

He then had to stop the site and contact us for help optimising the layout for the mansard floor. We noticed at that point that he didn’t even have building regulation drawings, so we had to go back to the beginning and liaise with building control, which the client had completely forgotten about – a real waste of time and money.

Alternatively, some clients may have been under the impression that they didn’t need to get permission from their neighbours. Suddenly, a council official is on site and the work has to be halted.

Time sensitivity is also something to think about. We’ve had clients who had a plan approved but not gone any further with it until a year later. In these situations, their council may have put Article 4 legislation in place in the area, so their plan may no longer be feasible.

In many cases, clients come to us precisely because they’ve made these mistakes and want us to rectify them. Naturally, we’re always delighted to help them, but it’s best to spare yourself the wasted time and money that comes with rushing ahead without the suitable HMO Planning drawings.


Hopefully, this article demystifies the levels of HMO Planning drawings needed not just for planning permission, but to ensure you have a genuinely working project.

The pitfalls of having the wrong plans can really set you back and cost you a fortune, so don’t be one of the many who wastes time and money unnecessarily.

Whatever stage you’re at, if you would like the security of a professional alongside you as you navigate through your HMO journey, please contact me or get in touch via our website.

If you’d like to talk to an architect that’s successfully helped hundreds of people get planning permission across the country, please get in touch.  

We’d love to help you. 

Picture of Giovanni Patania

Giovanni Patania

(Architect Director, Co-Founder)

Giovanni Patania is the Lead Architect and Co-Founder at HMO Architect and Windsor Patania Architects.

Originally from Siena, Italy, Giovanni worked as a Project Lead Architect at Foster+ Partners, designing Apple stores across the world,

An HMO Investor himself, Giovanni understands property thoroughly, both from an investor's perspective and technically, as an Architect.

With over 15 years of HMO development experience, working on over 150+ HMOs and a 95% Planning and Building Regulation success rate, Giovanni has the expertise and credentials to help you on your HMO journey."



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