• Michael Bukowski

Outbuilding - Permitted Development |Beginner’s Guide

Updated: Jan 23


The popularity of the outbuildings in the UK is unquestionable. They have been known under many names, a garden annex, garden building, log cabin, an outbuilding, an outhouse, a garden shed, a garden studio, a man cave, a summer house, a gym, and many more, you name it. We can find hundreds of articles on how useful they are, how it allows you to use the full potential of your garden, encourages outdoor activities and lets you reunite with nature or DIY guides how to make sure these structures are lawful and do need not full planning permission under Permitted Development Rights (PDRs) “The Town and Country Planning (General Permitted Development) (England) Order 2015”. In our opinion, the press release on the subject or even some professionals’ guidance very often lacks technical details and we have a feeling it is our due diligence to at the very least shed some more light on the subject.

What is a Permitted Development?

If the term Permitted Development or “The Town and Country Planning (General Permitted Development) (England) Order 2015”) is new to you, it is statutory legislation determining what developments do not require full planning permission which was introduced by the Government back in 1995. Ever since then the householders and developers are using the Permitted Development Rights to build a variety of buildings not having to ask the council for permission although it is strongly recommended to use a professional like a local architect to get it right and make sure the proposal is lawful.

Although the planning permission is not required, obtaining a Lawful Certificate for such a structure is strongly advisable to avoid any abortive work or to avoid any legal queries and ambiguities when selling the property. The full publication of the legislation can be found in the link below:

Types of outbuildings which do not require any planning permissions

The legislation says, “… any building or enclosure… required for a purpose incidental to the enjoyment of the dwelling house”. This includes structures like a gazebo, garden shed, greenhouse, detached garage, gym, hot tub or swimming pool, pond, hot tub or sauna cabin, animal shelter/kennel, enclosures for domestic heating oil, or petroleum gas or even an indoor tennis court and many other.

What are the criteria for Permitted Development Outbuilding?

Any ancillary garden building is considered to be Permitted Development not needing planning permission provided the criteria below are met:


i. The proposed structure must be detached and ancillary to a house and not to a flat, maisonettes, or other buildings.

ii. Only non-self-contained, non-habitable/ non-habitable use is allowed, meaning the sleeping accommodation (a bed) is not allowed, but sofa and armchairs, standard lounging furniture, is of course, permitted.

iii. They can also contain a W.C although in the past we have come across many ambiguities regarding a shower and cooking facility in an outhouse.

iv. The rule of thumb is that in case of a home office or a gym, provision of washing facility and a small cooker if justified can be found lawful.

v. Unfortunately, we also must mention Granny Annexe which is not Permitted Development as it is classified as living accommodation.

vi. Features like balconies and verandas are not permitted.

vii. It has no sleeping accommodation


i. Outbuildings located to the rear or side of the garden are generally a Permitted Development.

NOTE: It is important to remember that if a site is located on a designated land e.g. Conservations Area or Special Character Area (World Heritage sites, National Parks and the Broads, Areas of Outstanding Beauty) the outbuildings to the side garden are not allowed under Permitted Development Rights in which case planning permission would be required

ii. Outbuildings located forward of the principal elevation (usually front garden) are not allowed under Permitted Development Rights in which case planning permission would be required.

NOTE: principal elevation can also be a side elevation on a corner site facing the highway.

iii. Outbuildings located within the curtilage of Listed Buildings are not Permitted Development therefore a full planning process will be required.


i. In general, the internal floor area can be unlimited provided that together with all the other outbuildings and extensions the total area does exceed 50% of the site coverage (the total area of land around the original house)

NOTE: Since the use of the proposed outbuilding must be ancillary to the host building, (existing house) its size cannot be exceedingly large in comparison to the existing house so that there is no doubt about its ancillary use.

ii. Height:

§ only single-storey outbuildings allowed under Permitted Development Rights

§ if the outbuilding is further than 2m from any boundary the allowed eaves height is 2.5m and total height 4m with a dual pitched roof, otherwise 3m.

§ if the outbuilding is within 2m from any boundary the over height cannot exceed 2.5m

iii. Overall permitted height of patios and decking is 30cm.

iv. It is a single storey building,

v. floor area does not exceed 30sq.m and it is constructed of non-combustible materials or is located not less than 1m away from any boundary

vi. floor area does not exceed 15sq.m if constructed of combustible materials

Building Regulations for Outbuilding

Apart from the Planning Act 1995 part of which is “The Town and Country Planning (General Permitted Development) (England) Order 2015” the developments in the UK are also controlled by the Building Act 1984. Most of the outbuildings mentioned above may be exempt from compliance with the Class 6 Building Act 1984 meaning they do not require Building Control Application or Approval, provided the following conditions are met:


It has no sleeping accommodation


a) It is a single storey building,

b) floor area does not exceed 30sq.m and it is constructed of non-combustible materials or is located not less than 1m away from any boundary

c) floor area does not exceed 15sq.m if constructed of combustible materials

Is it right to build outbuildings on your own? Or,

Do you need to hire a professional for this job?

Let’s dig into this topic deeply, about the advantages and disadvantages of DIY outbuildings. Here are some important points to consider before building one on by yourself,

1. Great way to kill time on the weekend.

2. A good learning experience for kids.

3. Solid weekend experience/challenge.

4. Boasting rights at your next family BBQ.

5. It’s not relaxing work and may take many weekends.

6. Budgeting may go awry without adequate research for materials and machinery (comparing prices amongst suppliers).

7. Bit of heavy lifting depending on construction method.

On the other hand what are the advantages and also disadvantages, if you hire a professional,

1. They offer a higher standard of quality as they complete projects like this regularly

2. You know what to expect - the design and timeframe of construction

3. You need to do nothing at all, they can complete the design work during a few weeks

4. Very quick work and the work will be finished in a short time.

5. They can easily customize the project to better suit your needs

6. Contractor Cons:

  • You can’t claim it as a personal project

  • Typically costs more due to the cost of expertise and labor

  • Less control over the final product

General Advice

Identify potential issues on your Construction Site: Building an outbuilding can be very hard for you. You need to look for problems near the construction site which can make all your efforts in vain. Also, Trees in your yard can be dangerous, branches or leaves could fall and cause problems with your shed’s roof. Sometimes, tree roots may pose a problem to build the outbuilding in the first place and this is another consideration to keep in your mind. If you don't have an open area for the shed, consider removing some trees before (if they are not protected). Make sure that your construction site is level and it ensures a good drainage system. Otherwise, water will sit around your shed because the area has bad drainage and not at the same level.

Pay Attention to the Extra Features: Pay attention to the extra features when building a shed. Extra features will improve the function of your shed. If you need plenty of storage space to keep various tools within the shed then you must look for features that offer great shelving options. You may also want to add decorative trim, shutters, and a nice paint job that will make your shed look even better from the outside. Although the fun features aren't the most important part of the shed, it's nice to look for shed plans that offer features that make your shed just a bit nicer.

Right Size and Style: Choose the right size and style for your shed. You'll find more and more different outbuilding plans available, as you begin to look at shed building plans. You can choose different sizes of outbuildings, various styles, and more. The size of it will be a real important factor when choosing the shed/outbuilding. Consider how you want to use the shed and the room that you'll need, which will help you decide on the right size. Take into consideration the style of your home and property. And maintaining this will help you choose the right style for the shed you plan to build.

Materials and Equipment that you will possibly need for building an outbuilding,

v Reinforcing mesh

v Base course/gravel

v Sand

v Cement

v Concrete blocks

v Facing bricks


v DPM membrane

v DPC membrane

v Timber joists, battens, firrings

v Timber joists hangers

v Liquid waterproof membrane

v Water supply & hose

v Wooden forms and pegs

v String line for forms

v Wheelbarrow

v Measuring tape

v Appropriate nails and screws

v Shovel

v Spade

v Spirit level

v Wooden float or hand float

v Cement trowel

v Dust mask + safety goggles

v A carbide-tipped masonry drill bit.

v A hammer drill

v Overhead drill press

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