Does My Extension Need Planning Permission?

April 9, 2021
by Sege Rosella

Obtaining planning permission in the UK can be a very frustrating process – we’re a builder here in Kettering, Northants with decades of experience, so trust us, we know only too well the difficulties that some people have faced before getting to us. But if you approach the subject with the correct knowledge it needn’t be.

In this guide we’ve given you our top tips on how to navigate the planning system and how as experienced operatives in the area, how the team here at Mortar & Co can assist you with your application.

Do I need planning consent?

There is no simple answer to this question as each construction project is completely unique and it depends on lots of factors. Firstly, lets take a look at projects on the smaller end of the scale – if it meets the right conditions then it may not require planning permission under a scheme called ‘permitted development’ (PD).

What is PD and how do I know if my project qualifies?

This is a set of rights that was introduced by Parliament – rather than a local authority – to allow property owners (residential and commercial) to undertake a certain level of work without having to apply for full planning permission. These rights were relaxed further in May 2013 for a three year trial, and they allow quite a generous amount of work to be undertaken. Below is a short summary of what’s permitted:

  • You can extend the rear of your detached property by up to 8m if it’s a single storey extension or up to 3m if it’s two storey
  • If you live in a semi-detached or terraced property then you can extend the rear up to 6m for a single storey addition or 3m for more than two
  • Any rear extension has to be at least 7m from the rear boundary
  • You cannot extend the front of your house or any elevation that faces a public highway for that matter
  • If you want to extend the side of your property then you can only add a single storey development and the size cannot be any greater than 50% of the width of the original building
  • The maximum height for a single storey extension is 4m to the ridge and the eaves
  • The maximum height for a two storey extension is the same as the original building
  • An extension to the rear must not result in more than 50% of the garden being covered
  • With the exception of conservatories, any additions to the property must be of the same look and feel as the original building and use materials that blend in seamlessly

This sounds too good to be true – are there any exceptions?

Yes, but then you knew that was coming didn’t you? If you live in a Designated Area such as a Conservation Area, National Park, Area of Outstanding Natural Beauty or in a listed building then a different set of rules apply and can vary depending on your local authority.

Some local planning authorities have also removed elements of these rights in situations that fall outside the above areas. For instance, Westminster Council have removed PD rights from a handful of streets that they deem of significant historical importance.

Another important detail to take into account is that each property is allocated a certain amount of PD from 1948 onwards. This means that if any prior owners of your property have completed work under PD since then to now, it counts towards the total development that you are allowed.

Anything else I should know?

There are also PD rules that govern outbuildings and improvements such as loft conversions. The best course of action is either to call your local planning authority to discuss the intricacies the of your project or a local building company, such as us here at Mortar & Co, will be able to advise you as part of a free initial consultation – just pick up the phone.

If you’re looking at building a more substantial extension, or say, one that is of a contrasting style to the original property the chances are that you’re going to have to apply for full planning permission.

I’ve heard that obtaining planning permission is the hardest part of the project

This can certainly be said for some projects, but this sort of situation only usually arises for the most complex of projects. Gaining planning permission can also be difficult when poor advice is dished out in the first place and an applicant tries to obtain permission for something that will be granted in a million years, either because it’s plain against the rules or would disadvantage the local community in some way.

And yes, the tales that you’ve heard about the process being a bureaucratic nightmare can be true, but you have to remember that you’re dealing with a tranche of the government so it’ll always be the case to some extent.

How to make the process go as smooth as possible

To begin with you should always take on board the advice of the professionals around you: designers; builders; estate agents, etc., to make sure that what you are looking at building is realistic in ambition and scope. What we mean by this is if you’re going against the advice given and trying to increase the size of your house by an amount that is not likely to ever be approved, or adding elements to your Grade 1 listed house that are against the rules, then you’re likely to find yourself with a very drawn out, messy, stressful and ultimately unsuccessful planning application.

One of the costliest mistakes that people make is to not plan fully and change their minds or make some kind of alteration halfway through an application that could have been avoided in the beginning. If you end up withdrawing an application then not only will you have to resubmit and repay all the fees; you’re also going to have to shell out more money to have your designer make any amends to the plans. As the old adage by Benjamin Franklin goes: “By failing to prepare, you are preparing to fail”.

The most efficient and speedy results come when you instruct people, such as Mortar & Co, to manage the planning application on your behalf. As has already been written, we have established relationships with the key players in the local authority and we have invaluable knowledge of the types of things that the local authorities we deal with like and dislike.

Do I need to make a pre-application to the local authority?

Each project is entirely different and there are lots of reasons why a pre-app may or may not be required. The idea behind a pre-app is that you take preliminary designs – sometimes even sketches and photos of the site – to your local authority to gauge the likelihood of full planning permission being granted or to find out exactly what extras/concessions they are likely to require in advance. The idea is for this informal process to save you, the applicant, both time and money. However, in recent years this process has started to become a lot less informal with some councils charging up to £400 for this privilege, so it’s worth checking in advance.

A good designer and builder should be able to advise you if you need to go down this route. Here at Mortar & Co some of the reasons that we might take a project through a pre-app are as follows:

  • If the extension if uniquely complex
  • You may be approaching the boundaries of your property
  • If you’re adding 50% or more to your property’s original footprint
  • You’re wanting to build in a Designated Area
  • If the addition to your property is of a contrasting style to the existing
  • It seems likely that the development will impact neighbours

Submitting a full planning application

Once you’ve worked with your designer and decided on the design, worked out the precise location, sizes, access routes and all the other details, your designer should have produced a complete set of technical drawings and plans, which not only include all the aesthetic modelling and elevations, but also all the technical details such as:

  • Drainage
  • Foundations
  • Type of materials
  • Detail on how the structure interacts and joins with the existing
  • Utility scheme – electricity, gas etc
  • Access routes

This is a non-exhaustive list, but it gives you a good idea of the level of detail that your application will require.

Although not legally required anymore, a design and access statement can still add value to an application – particularly if there’s a degree of complexity or something out of the norm to what you’re trying to achieve. After compiling this information it will then be submitted to the planning department electronically and this is when any fees will be due by the council.

How long will it take to get a decision?

As ever, there is no hard and fast rule to determine this. In our experience, if a planning application is submitted with all the relevant details and runs into no hiccups along the way then you can expect to have a decision in about 8-10 weeks.

What are the different outcomes?

Your application will either be approved, approved with conditions or refused. An approval is usually obtained in one of two ways: either the case officer that has been assigned to your application is able to see the process through from start to finish and award a decision; or in the case of any objections from neighbours or other parties it’s likely the decision will go to committee. If this latter scenario happens then the local authority will inform you and give you a detailed report. You will then have the chance to speak at the committee hearing to help your project with any necessary information. If you’ve employed the services of Mortar & Co to field your application then we’d take on this responsibility for you.

Can I appeal?

Sometimes, even the best-prepared submissions backed up by leading architects and lawyers can be denied by the council. If your application is denied then the council will tell you why explicitly and if there’s an opportunity to amend any details then you will be invited to and the resubmission will be free of charge.

If this option isn’t open to you then you are entitled to fully appeal the decision. Be warned though that this can be a long and costly process. Before venturing down this route it’s worth speaking to your designer and planning consultants as it may turn out that there’s a better way of obtaining planning, such as redesigning part of the development and resubmitting the new application.

How can Mortar & Co help?

Over the years we’ve dealt with hundreds of planning applications for our clients. People tend to come to us in one of three scenarios:

  1. We’ve been commissioned to undertake the full design as well as construction of the client’s project. This means that we deal with the entire planning process in the role of an agent on behalf of the client before moving onto the project management and construction phases
  2. We’ve been commissioned to undertake the architectural design of the new property and we produce all relevant technical drawings for the client to submit to the planning authority
  3. A client has submitted a planning application, but somewhere along the way amendments are needed to their plans (for instance, if building regulations hadn’t been sufficiently met) and we help to rectify the situation

We see the most problems occur when a client has been ill-advised before submitting an application – sometimes it will just be impossible for your particular scheme to be granted permission, no matter how well-intentioned it is. It’s always worth seeking the best advice before submitting an application, so if you have any questions regarding any point of the process feel free to shoot us an email or call us on 01536 525229 and we’d be more than happy to give you advice. As always, completely free of charge.