I’ve found a plot with planning consent — do I have to build the approved design?

Looking for a building plot can be a real challenge, especially if you don’t have specialist land finding skills. Most people end up browsing sites like Rightmove or Plotfinder, where many of the available plots already have planning consent in place.

This might seem like a convenient solution, but for most people dreaming of building their own home, they’re looking for something that reflects their personal tastes and fits the unique needs of their family. That’s where the dilemma comes in if the approved design isn't exactly what you had in mind. So, do you have to build the design that’s been approved, or can you apply for something new and different once you have found a building plot?

Before jumping one way or another, it's first worth knowing that a building plot is not restricted to the approved design once planning consent has been granted. Depending on the circumstances there’s thousands of alternatives and it’s perfectly acceptable to apply for a new consent for a house you do want to build. But before kicking off the planning process all over again, it’s worth considering a few key issues.

The planning process: Should you start over?

Before you decide whether to stick with the approved design or try for something different, one of the first questions to ask is whether it’s even sensible to start the planning process all over again. The reality is that the planning system can be slow and complicated and there’s plenty of stories of planning applications dragging on much longer than expected. In some cases, submitting an entirely new application might feel like opening a can of worms, so it’s not always the best option and can often become a plot buying mistake.

Another important factor to consider is whether the original planning consent faced objections. Planning applications are often contentious, and it’s common for neighbours and consultees to raise concerns during the consultation process. While many objections are immaterial and easily dismissed, any that are significant will need to be addressed in the new application.

If the original consent was won on appeal, or was granted for something like a house of exceptional architectural merit (such as under Paragraph 84), the process was likely a difficult one, and applying for a new consent could be extremely challenging. In cases like these, it might be best to stick with the existing approval and avoid reopening a lengthy planning battle.

Do you like the approved design?

Now that you’ve considered the planning process, it’s time to turn your attention to the design itself. It’s not always easy to know exactly what we want in a home until we see it, but most of us do have opinions about design, whether we realise it or not. The first thing to consider is whether the design that’s already approved actually works for you. Do you like it? Will it need your needs? Or does it not quite fit with the vision you had in mind?

If you have strong opinions on what you want, this can quickly become a black-and-white issue. If the approved design doesn’t match your aspirations, you’ll want to explore alternatives. This is where a planning professional is really helpful. They can help you assess whether changes to the design are possible, based on the plot’s constraints, the applicable planning policies, and the overall impact in the setting or street scene. A good planning professional will also take into account how difficult the original approval process was, and whether any new objections might arise if you submit a revised design.

In many cases, objections from neighbours are less about the specific design of the house and more about whether any house should be built at all. So, changing the design of something that’s already been approved is often not a big deal. That said, local planning authorities will still have their own opinions about how the new design fits in with the surrounding area, so be prepared for some scrutiny from the officials.

Can you make minor changes instead of a full redesign?

If the approved design isn’t exactly what you want, but it’s not totally unsuitable, you might not need to go through the hassle of submitting a completely new application. Instead, you could explore making minor changes through what’s called a “non-material amendment.” A non-material amendment allows you to make small changes to the approved design without breaking any of the conditions placed on the original consent. This could mean shifting windows, altering the functionality of certain spaces, or even making the house slightly smaller.

However, if your desired changes are more significant, such as increasing the size of the house, altering the exterior appearance, or moving the structure closer to a neighbour’s property, you’ll likely need to submit a new planning application.

In this case, you could apply for a “material amendment,” which allows for larger changes to the approved design under Section 73 of the Town and Country Planning Act 1990. A Section 73 application lets you vary or remove conditions tied to the original planning permission. While there’s no strict limit on how much you can change with this application, it’s important to note that it doesn’t extend the original consent’s expiry date.

Can you afford to build the approved design?

Even if the design is something you could live with, its essential to check that you can afford to build it. Most of us have a budget we need to stick to, and building costs are often higher than expected. One of the biggest factors influencing cost is the scale of the project. The larger and more complex the house, the more expensive it will be to build. Before you commit to buying a plot, it’s essential to run the numbers to make sure you’re paying a fair price for the land, and that you have enough left in your budget to cover the costs of building a house.

In some cases, the approved design might be difficult or risky to build, especially if the previous architect got a little carried away. For example, certain design features might be overly complex or require specialised building techniques, which could inflate costs significantly. If this is the case, it might be possible to address these issues through a non-material amendment. However, if the design is particularly challenging or risky, starting over with a simpler design might be the better option.

One thing to keep in mind is that landowners who sell plots after securing planning approval often don’t fully understand the costs associated with building the approved design. It's therefore not uncommon to find that many ‘oven ready’ plots are overvalued and unviable. In recent years, high inflation and stagnant house prices have only made this problem worse. Many plots have therefore come onto the market with approved designs that are simply too expensive for the original owners to build who then then look to sell them.

As a self builder, it’s important to avoid getting trapped in a situation where the plot is affordable, but the house you want to build isn’t. It’s therefore essential to crunch the numbers to make sure everything stacks up. If it doesn’t, now’s the time to get back on the drawing board and come up with a proposal that’s viable.

Don’t forget to check the planning consent expiry date

Another important consideration when buying a plot with planning consent is the expiry date. Planning consents have an expiration date, and typically, if you don’t start the build within three years, the approval will lapse, and you’ll lose the consent.

Before making any decisions, be sure to check how much time is left on the approval. If the deadline is approaching, you may need to act quickly to start the build – or even consider submitting a new application to refresh the timeline.

But be careful here. While submitting a Section 73 application to make changes to the design can allow you to tweak the conditions, it won’t extend the expiration date of the original consent. If you’re running out of time, you might need to go through the full planning process again to ensure you don’t lose the approval altogether.

Understand the planning conditions

Finally, it’s essential to thoroughly review the planning conditions that come with the approved consent. Planning conditions are essentially the “fine print” of the approval and can sometimes create complications down the line. For example, you might find that the approval requires specific visibility splays for access points – areas that may cross onto third-party land that you don’t own. In cases like these, you could face difficulties discharging the conditions without compensating your neighbours or negotiating access rights.

If the planning conditions are too difficult or costly to fulfil, it might be worth reconsidering the entire project and starting the planning process from scratch. Designing a new house that doesn’t have the same access issues or other restrictions could save you a lot of headaches in the long run.

Weighing up your options

At the end of the day, deciding whether to stick with an approved design or apply for something new comes down to a balance of practical and personal considerations. The planning process can be slow and complicated, but if the approved design doesn’t fit your vision or your budget, there are options available – whether it’s making minor tweaks or starting fresh with a new application.

With the right professional support, finding the best approach isn’t too difficult. So, to make sure you don’t get stuck with a project that doesn’t work for you, just be sure to thoroughly evaluate the design, the cost, the time involved and any planning complications before making your decision.

If you've recently seen a plot you like the look of for a self build project, it's firstly important to assess the plot's potential. You can do this by taking a look at any planning conditions it might have as well as taking a closer look at the plans themselves.

It is also worth checking if the plot is located on a flood plain or a conservation area as well as making sure you are fully aware of any potentially expensive problems like needing foundations for difficult sites, or even Japanese knotweed.

Once you are confident in your checks, be sure to factor in other expenses such as stamp duty on a building plot.