Planning on updating your home in the coming months?
Embarking on a home renovation, extension, or self-build project is an exciting milestone… but navigating the ins and outs can be overwhelming to say the very least.
Especially when you consider how many thousands of householder planning applications are delayed or outright refused.
Not because the project is impossible, but because preventable errors were made during the initial application stage, highlights Simon Rix, professional planning consultant, and founder of Planix.uk, who specialise in advising people for small- to medium-sized projects.
“I get a lot of people who think because what they want to do is simple, they don’t need expert help or advice; and they can just do a simple sketch of what they want to do – and submit that to the council for permission,” says Rix.
“Literally, hand-drawn sketches, or even just photographs, and think that’s enough. You need proper technical drawings to be submitted that are the right quality, right size, and right scale.
“And if you don’t meet all those criteria with your drawings, then it’s not even going to get through the first stage which is the validation stage of an application.”
To give your scheme the best possible chance of securing approval from your local authority, here are three crucial mistakes to avoid…
1. Designing in a vacuum – and ignoring the current policy
The single biggest mistake homeowners make is assuming that because a neighbour down the street built a two-storey extension, they can automatically do the same, underlines Rix.
“People often say to me, ‘Oh, they’ve done this down the road’. I say, ‘Yeah, but when was that done?’
“If it was done 20 years ago, and the current policy was only adopted three years ago, then what was done before three years ago is irrelevant.
“It’s the current policy that it’s judged at. People don’t realise that in a planning officer’s opinion, past mistakes don’t justify new mistakes.”
Planning decisions are governed by strict local planning policies, conservation constraints, local design guides, and spatial plans specific to your local area, explains Rix, not just national guidelines.
Moreover, he says designing a dream layout without first checking your local planning authority’s Supplementary Planning Documents (SPDs) is a recipe for refusal. Local policies set out precise rules on building heights, boundary set-backs, matching materials, and street scene aesthetics.
“If your design blatantly flouts local guidance, planning officers will not tweak it for you; they will issue a refusal,” Rix says.
“Always conduct thorough desktop research or consult a planning consultant before committing to final architectural drawings.”
He continues: “More and more people are getting AI to do photorealistic, computer-generated graphics – images of what it would look like.
“That doesn’t work. You need to have technical drawings of what you want to do.”
So aligning your vision with local policies right from the start, saves both time and substantial redesign costs.
2. Submitting poor-quality or inaccurate drawings
Your planning application is judged almost entirely on the documentation you submit…
As Rix emphasises, skimping on detailed architectural drawings or relying on inaccurate sketch plans is one of the fastest ways to get your application invalidated or even rejected by the council.
“Planning officers need precise, scaled drawings including existing and proposed floor plans, elevations, site block plans, and accurate location maps.
“Inaccurate boundary lines, missing dimensions, or vague representations of adjoining properties raise immediate red flags.”
Furthermore, he says if key technical assessments – such as flood risk assessments, tree protection surveys, or ecology reports – are omitted when required, your application will stall before it even reaches a decision maker’s desk.
For example, if you’re in a flood-risk zone, it doesn’t mean you can’t do anything. “But you need to supply the right justifications. The rules are complicated and you need someone to argue the point,” explains Rix.
“You can’t just assert ‘Well, I’ve never had a flood here in 20 years’, which again, lots of people think they do can do.
“If the environment agency has you in a flood zone, you’re in the flood zone. That’s their predictions about what might happen in the future, not what’s happened in the past. Therefore, you’ve got to supply the right reports for it.”
Clear, accurate, professional drawings demonstrate respect for the process, build credibility with the planning officer, and ensure your proposal is evaluated on its actual merits rather than ambiguity, underlines Rix.
3. Failing to address neighbour impact and privacy
Planning officers have a statutory duty to protect the living conditions of nearby residents…
Ignoring how your project impacts your neighbours – specifically regarding overshadowing, loss of daylight, overbearing impacts, and overlooking – is a classic mistake, highlights Rix.
“So if you propose a first-floor extension, and have a new window that allows you to have a new view into someone’s rear private garden, that’s going to get turned down… because it’s impacting someone’s privacy of their rear garden.
“Obviously, front gardens are different because that’s publicly viewable.
“But a private rear garden… again, I say this to people and they say ‘Oh, but I’ve already got views into their rear garden from this other window’.
“The response to that is, two wrongs don’t make a right. That existing window might have been put in before the current rules, and it’s about a new way to negatively impact the privacy of your neighbours which will be resisted.”
Therefore, submitting plans that place new first-floor side windows directly facing a neighbour’s bedroom or private outdoor space will trigger instant objections and officer resistance, warns Rix.
To avoid this, he says to carefully assess the ’45-degree rule’ for daylight, position windows thoughtfully, and consider privacy screening or obscure glazing where appropriate.
Better still, communicate with your neighbours before submitting your application. “Neighbours get annoyed when they get surprised by things,” says Rix.
“My advice is to talk to them before you submit anything. You don’t want your neighbours to first hear about it by a letter from the council, or a notice on the lamp post.
“You want to be the one telling them that you’re going to do this, and the worst thing that can happen is they’re still going to be against you – but at least you’ll know.
“You’ll know their arguments because they’re going to be voicing them, and you can either decide to try and accommodate their objections and adjust your plans; or perhaps their objections are totally unreasonable, and you don’t want to adjust your plans.
“At least you’ll know what their objections are, and therefore you can preempt them. You can rebut them in your actual application. But if you don’t talk to your neighbour, you’re not going to know what their objections are.”
Showing them early drafts, listening to reasonable concerns, and making minor adjustments beforehand can stop bitter objections before they start.
Indeed, he says a project which respects neighbour amenity flies through the system far smoother than one bogged down in local disputes.
Securing planning permission does not have to be a battle…
By understanding local planning policy, investing in accurate drawings, and respecting your surrounding context, he says you eliminate the main triggers for refusal.
“Take time to prepare thoroughly, get proper advice early, and turn your building project into a smooth planning success,” says Rix confidently.
For more tips and advice, visit the Homebuilding & Renovating Show, September 18-20, Excel London. To claim your free tickets, visit homebuildingshow.co.uk
