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TWO WAYS Permitted Development Could RUIN YOUR HOME

Updated: 23 hours ago


permitted development is not the solution to every house extension
Two ways permitted development could ruin your home



If you own a home in the UK you might be aware of something called permitted development. It's the right to make modest alterations or extensions to your home, without needing planning permission. Small extensions to the rear, a porch to the front or dormers on the roof. That kind of thing.


This was introduced in 2015 because it solved a problem for the government. By creating permitted development rights, the government hoped to remove lots of small, but time consuming, application from the planning system. They could then reduce the number of planning officers employed by each local planning department.


Permitted development exists because of austerity. It facilitated cuts to local authority budgets.


Ive been a self employed Architect in the UK since 2009, specialising in altering and extending private homes. You would think I might use permitted development regularly but in all that time I only used it on one project. Im going to talk about this project later but I should be clear up front, this is not a guide showing you how to design something to avoid the planning system.

There are lots of rules around permitted development;

measurements from boundaries, areas of garden, volume of roof, height to the eaves. Etc. I cant easily post about these rules because they vary between England, Scotland, Wales and Norther Ireland. The system also allow local authorities to place restrictions on permitted development rights, so there are variations even at the local level. But the most important thing to understand, is that permitted devilment rights can vary over time.

Im not saying permitted development is wrong but there are two big mistakes I see people making. And I want to talk about this so you don't fall into the same trap. The first big mistake can limit your quality of life, for no good reason. The second big mistake could lead to huge financial consequences and ruin your home.

Ok, so the first big mistake people make with permitted development is to design their extension around the rules just to avoid going through the formal planning application process. Now, I get why people in the UK see the planning system as terribly risky. The media love a good horror story about the planners but it really isn't sensible to limit the design of your home out of fear of this process. And yet, that is exactly what I see people doing.

The reason this project is the only one Ive built using permitted development is because I was able to persuade everyone else to go through the regular planning process to get a bigger extension.

What a permitted development house extension looks like
I designed this house extension in Edinburgh under the permitted development rules

This project worked out exactly as the client wanted, the extension gave them all the extra space they needed, so permitted development worked for them. But I have lost count of the number of people I have met who started off the process desperate to avoid the planning system and willing to build a much smaller structure if that is what it took. It's a false economy. The planners aren’t paying for your house extension and they aren’t going to live in your house extension. It should be designed to suit your lifestyle, not their rules. If it means going thought the regular planning process to make that happen, then go for it.


I recently wrote a post showing the four biggest mistakes people make that guarantee their planning applications are refused. The point being, to show that the system will work, most of the time, provided you understand a few simple rules in advance. Hopefully it will help remove any fear you have about the planning system. Don't let permitted development rights talk you into getting less than you need.


The second big mistake I see people make with permitted development is they assume that as long as they build their extension to the rules, it will be legit. Not so fast. There are two things which could ruin you home;


Politicians and the financial sector.

The thing about rules is that politicians love to change them. I mean what’s the point of having power if you don't use it. All it takes is for lobby groups to persuade the government that permitted development has gone too far and should be rolled back. It's also possible for local authorities to restrict permitted development rights in your area. What was once acceptable, might no longer qualify as permitted development if the council are lobbied by local residents. Now, why would this cause you a problem if you built your extension to the rules as they were at the time. The answer is something called a certificate of lawfulness.

This is essentially a letter from the planning department confirming that the design of your new extension or attic conversion does actually have permitted development rights. This could become a major issue if you try sell your house. This is where the financial sector comes in. If a potential buyer has a mortgage, and many of them do, the mortgage lender wont release funds unless a chartered surveyor inspects your home and writes a report.


Most of you will be familiar with this process but one of the things that surveyor will look for is alterations to the existing house. When they spot the extension you built, they will ask whether you got planning permission.

“Didn't need to, its permitted development”.

“Ok, do you have a certificate of lawfulness to prove that?”

At this stage you might be thinking it's nothing more than a bureaucratic exercise. You fill in a form, pay fee and the local council will eventually give you the stamp of approval.

The problem is, a certificate of lawfulness will only consider your building in relation to the permitted development guidelines on the day you make the application. If those regulations changed over time they wont cut you any slack. Sending the council screenshots of Facebook posts when you built the extension back in 2017 wont help. They aren’t going to be flexible on this.

Side note, the building regulations operate the same way if you make an application after construction is finished.


So what next. If your extension doesn’t actually have permitted development rights, and you’ve alerted the local council, you will be asked to make a retrospective planning application. All bets are off. This will take months and you property sale will be on hold until it's resolved. Now, the worst case scenario is that your retrospective planning application is refused and you appeal the decision, only for that appeal to also be refused. At that stage you are looking at demolishing the structure.


If you are considering using permitted development rights to build a modest extension to your home. I advise you carry out the application for certificate of lawfulness before any building work starts. This isn't advertised to your neighbours and it doesn’t get posted on the local planning portal. It's a private matter between you and the local council and the fee is usually half that normally charged for a planning application. If the council reject the application you can either revise the design to confirm with the rules for permitted development or go for a full planning application to get what you really want. I should point out that local authorities don't require certificates of lawfulness as standard. The whole point of permitted development is to limit the time planning officer send assessing this kind of thing.

Certificates of Lawfulness have been around for a long time but lawyers working for the big mortgage lenders stared asking for them in recent years, after homes altered using permitted development were put up for sale.

This is from the Nat West website discussing permitted development. They describe a certificate of lawfulness as something which protects homeowners when they sell their property.


Nat West Bank opinion on permitted development
highlighted note from the Nat West website

Homeowners are not legally obligated to have a certificate of lawfulness but the system can still turn your life upside down if you don't have one. So make that application, even if you used permitted development in the past, get the certificate of lawfulness now before the rules change.

If you are thinking of altering or extending your home and you want to discuss options, you can book a consultation with me. Please check the terms and conditions before you book a session.


So how did this project comply with permitted development rights.


permitted development guidelines allowed this house extension
An open garden room extension, Edinburgh. Designed to comply with permitted development guidelines

This was built in 2018 in a suburb of Edinburgh and the extension was more than 1 meter from the boundary, the roof was not more than 3 meters above the ground and the extension took up less than 50% of the rear garden. Once the design was worked out, I applied for a certificate of lawfulness.


permitted development house extension UK
Main elevation of the house extension, with bi-fold doors fully open

floor plan of a house extension designed to comply with permitted development
The original floor plan had sliding patio doors but the client changed their mind, and used bi-fold instead

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