Conservatory planning permission – and how to plan your space

Everything you need to know before investing in a conservatory - from planning permission to the best materials for your needs

If you're considering adding a conservatory onto your home, there's a fair amount you need to know before getting started. Understanding conservatory planning permission will ensure you don't face any problems further down the line, and create a problem-free space.

Whatever conservatory ideas you have in mind, it's important to lock down the practical, need-to-know factors first. To plan a conservatory, you need to know what you can do, how to get it started and what materials will work best for you.

Whether your aim is for extra living space, to bring more light into your home or simply to enjoy your garden all year round, these areas are necessary to achieve your goal.

Conservatory planning permission

So let's answer all the questions you have about how to plan a conservatory - including those you haven't even thought of yet!

What is a conservatory?

conservatory with wooden floor and pillows on sofa

(Image credit: Future PLC/Polly Eltes)

First things first - what even is a conservatory?

Popular amongst the Victorians, conservatories were originally built to hot house their beloved exotic plants. Traditionally described as separated from the rest of the house by a set of external quality doors, the idea of the classic ‘bolt-on’ conservatory has been changing.

‘Now we are seeing more and more designed as an integral part of the house, used as an addition to the main ground floor living space,’ says David Salisbury, MD of David Salisbury.

Available in classic Victorian and Edwardian-inspired, as well as modern designs, conservatories can be made to fit the side or rear of the house. Alternatively being made to wrap around a corner, to make the best use of available space.

Although the names are often used interchangeably, there is a difference between a conservatory, orangery and a garden room.

What are the design differences between conservatories, orangeries and garden rooms?

conservatory with white coloured and sofa

(Image credit: Future PLC/Colin Poole)

There are a few key differences between these three terms.A conservatory is made largely of glass, including its roof. Orangery ideas have more brickwork and are more of a flat-roofed extension with large glass windows and a roof light, while garden room ideas usually have walls, a solid roof and generous windows. These ‘hybrid’ rooms make good use of modern advances in high performance glass, designed to minimise heat loss in winter and heat gain in summer.

One of the key traits that traditionally separates a conservatory-type structure from an extension is the presence of an external-grade locking door, between the addition and the main house. There is also a limit to the permanent services such as water, drainage and heating that can be installed too.

To all intents and purposes, it is a stand alone building attached to the main house. But this has changed in recent years with many conservatory companies creating open extensions in the classic conservatory style. These can house a conservatory kitchen ideas or a dining zone that is open to a kitchen in the main house.

Classic designs are most popular with shapes and designs influenced by the Victorian and Edwardian periods. A conservatory can be designed to fit a range of footprints to the back or side of the house, or can wrap around one corner to make the most of all available space. Construction materials include UPVC for low maintenance affordability, timber for its sustainable qualities and traditional look, and aluminium for its sleek, contemporary design, strength and anti-corrosion properties.

Do you need planning permission for a conservatory?

conservatory with white window and glass door frames

(Image credit: Westbury Garden Rooms)

This isn't actually as simple a question as you might think.

'Conservatories which are designed and built under the principle of permitted development do not require planning permission,' says Karen Bell, Sales Director, David Salisbury.

'Permitted development rights are an established grant that a house might already have in place,' explains James Upton, Managing Director, Westbury Garden Rooms. 'This allows some building works to be undertaken without having to make an application for formal planning permission, as you would with a loft conversion or a new porch.'

However, while the bulk of conservatories are considered to be permitted development, this isn't the case for every build.

'Orangeries and garden rooms create more space in your home and completely change the look of your property,' notes James from Westbury. 'Therefore it can be likely that you’ll need planning permission. Many of our orangeries are built onto Grade II Listed properties, in AONB and conservation areas where planning permission is even more likely to be needed.

So what do you need to be aware of if you want to avoid applying for planning permission?

How big can a conservatory be without planning permission?

conservatory with white coloured and tree

(Image credit: David Salisbury)

'Under permitted development, you can extend up to 4m on a rear extension and 4m in height,' says Karen from David Salisbury. 'Under Prior Approval, the depth doubles. For side extensions, the conservatory will need to be less than half of the width of the original property, as long as it is adjoining an original house wall.'

'There are restrictions to these rules,' continues Karen. 'These include if your home is listed (you’ll need Listed Building Consent to make any changes to a listed building) or situated in a Conservation Area, or is a new build where permitted development rights are usually removed.'

Whether yoy're working with large or small conservatory ideas is important for determining if you need conservatory planning permission or not. 'Changes were made to permitted development rights on the 30th May 2019,' says James from Westbury. 'Larger rear extensions are now allowed but do require prior notification in the form of a lawful development certificate (LDC). These go up to 8m in depth for a detached house and 6m in depth for a semi-detached house.'

Do I need a door between a house and conservatory?

house and conservatory with potted plant

(Image credit: Future PLC/James Merrell)

One thing you may not have considered in terms of how to plan a conservatory is whether you need an internal door or not.

'If you are opting for a traditional conservatory, you will often have to have a door between your house and conservatory due to heat loss,' says James from Westbury. 'This is something that can be required under building regulations. However, if you opt for a timber frame orangery this is not always a requirement due to the superior insulation.'

'In order to comply with building regulations, if the conservatory is separated from the house with external grade doors and is less than 30 metres squared with more than 75% glazing in the roof then buildings regulations would usually apply,' adds Karen from David Salisbury. 'However, it is good practice to ensure that any structure complies with building regs so that it can enjoyed all year round.'

What are the building regulations?

conservatory with round table and chairs and dog

(Image credit: Future PLC/Colin Poole)

Building regulations will generally apply if you want to build an extension. If your conservatory is built at ground level; is less than 30 sq m in floor area; has an independent heating system; and is separated from the house by external quality walls, doors or windows – it is normally exempt.

However, even if the conservatory itself is an exempt structure, any new structural opening between the conservatory and existing house will require building regulations approval. Part L is an important, relatively recent update to the regulations, covering all matters thermal.

You may also need to involve your neighbours. The Party Wall Act 1996 provides a framework for preventing and resolving disputes relating to party and boundary wall

How do you plan for a conservatory?

conservatory with cane chair and cane table

(Image credit: Westbury Garden Rooms)

As with anything building, construction or design work, you need to know where to begin.

'As a starting point it would be useful for the homeowner to know if their project has any requirements for planning, if there are any listed elements, or if their home is based in a conservation area,' advises James from Westbury. 'We would also advise that homeowners know the rough dimensions of the size of the room they have envisaged to help them plan the project.'

Appearance and use are important, too. 'Design, space and light are the  key factors to consider,' says Karen from David Salisbury. 'But, more anything, functionality is paramount – consider how you see yourself using the room.  A new conservatory will usually become the favourite room at home. So lifestyle and how you use your home and garden will need to contribute to the design brief.'

Karen also explains what the key criteria experienced designers will focus on. 'Budget. Lifestyle. How the new room is going to be used. The furniture you intend to incorporate. The architecture of the existing home, which will be a key influence on the final design.'

What materials can you use?

wooden conservatory with grey sofa and potted plant

(Image credit: Prime Oak)

' The majority of a conservatory will be manufactured from glass, with the roof tending to be fully glazed, which is a distinguishing feature of these types of extension,' notes Karen from David Salisbury. 'The frames will usually be manufactured from uPVC, aluminium or timber, for which each require different budgets.'

uPVC is the best for low maintenance affordability. Aluminium is known for its strength and anti-corrosion properties and is great for modern conservatory ideas. Wood is one of the most luxurious choices, and although it can be expensive, it is the most eco-friendly option.

'Oak framing utilises traditional construction and carpentry methods which local authority planners often welcome especially in period settings,' adds David Handley, Commercial Director, Prime Oak. 'This is due to their subtle, natural appearance. Also with the provision of an increasingly important sustainable solution in terms of sourcing materials from renewable responsibly managed forests and with regard to future re-use and recycling.'

Can I put a orangery/conservatory on the front of my house?

conservatory with trees table and chairs

(Image credit: Vale Garden Houses)

'In theory, yes, a conservatory can be designed and built for any elevation of a property, including the front,' says Karen from David Salisbury. 'If your property is listed or in a Conservation Area, gaining such approval can be tricky due to the impact on the amenity.'

'If Planning Permission and space allows, there is no reason why you should not be able to put a conservatory on the front of your house,' adds James from Westbury. 'This is not something that we see very often. Most people attach their conservatory or orangery to the living space that is often at the back of the house such as the lounge, dining, or kitchen area. When positioning a conservatory on a property our aim is always to make the most of the surrounding views, be this at the front or back of the property.'

What you need to know about glass extensions?

conservatory with navy blue colour and trycycle

(Image credit: Future PLC/Jonathan Gooch)

There’s no denying a contemporary glass structure can make a striking addition to your home. The trend towards simple glass ‘boxes’ with minimal framing is not just about crisp architectural looks. It is a popular option with planning departments. Especially for period properties, as there is no attempt to create a pastiche.

A glass box is upfront about being an addition, with the added bonus of being transparent so the original building can still be viewed beyond.

The most important factor is the performance of the glass and the expertise of the supplier. If you want to avoid the too-hot-in-summer and too-cold-in-winter scenario – we suggest that you invest in high performance glass. Be prepared because this may come with a price tag somewhere between £1,800 and £2,000 per sq m.

New technology is being incorporated into glass units all the time, making large expanses of glazing both practical and efficient. Budget in the region of £15,000 upwards for a glass extension project. This includes architect and structural engineer’s fees as well as the relevant planning processes, materials and labour.

How to choose an architect

conservatory with white coloured potted plant

(Image credit: Future PLC/Nick Pope)

Many conservatory companies often offer a complete turnkey service, from design to obtaining planning permission to build. However, more individual conservatory extension ideas are likely to need an architect.

Consult the Royal Institute of British Architects (RIBA). Its UK directory of members allows you to search more than 3,000 UK firms by name, location, area of expertise and services offered. You can ask locally for recommendations, view online portfolios and examples of past projects.

What else should you consider?

conservatory with white coloured and dining table

(Image credit: Future PLC/Carl Hodgson)
  • Consider the aspect; a south-facing extension may be too hot and too bright for comfort
  • Reduce glare and control temperature with blinds. Some use coatings to help reflect heat and glare in summer and retain warmth in winter
  • Ventilation is important. Do consider automatic opening roof lights, so that your room never gets too hot, even in the height of summer.
  • One of the most effective methods of heating a glass-walled room is by installing underfloor heating.
  • Rather than masses of downlights, do think about lights at different levels to add interest.  We suggest using some some uplighters by the doors, some table lamps and then some downlights around the perimeter. This will make the room seem larger.
  • When it comes to finishes for furniture and décor – choose fade-resistant materials – such as natural stone and porcelain tiles. Don't forget to line curtains and blinds.
  • Extraction is essential in an open-plan kitchen and down-draft extraction is an excellent that requires no wall or ceiling fitting. It rises from the work surface when in use and disappears discretely when not.

For more details, consult the UK government’s online planning resource.

Whichever structure you choose one thing's for sure, you won't regret adding space to your home.

What are the benefits of a lean-to conservatory?

‘The decision to install a lean-to conservatory onto your home will bring a wealth of benefits' says Brendan Day, National Sales Manager, Apropos. 'The adaptable style can help use dead space in properties that would not otherwise be extendable.'

A reverse lean-to shape can fit under low eaves, suiting a cottage. In addition, a lean-to is often the most economical choice of home extension as the structure is simple yet striking. It also gives a smaller project the illusion of a large, light-filled open space.

Can I fit a conservatory in a courtyard garden?

‘Anything is possible, but there may be constraints, such as the restrictions of your house, whether you are fixing to your neighbours' walls, or drainage,' says Stephanie Hill, Design Director, Trombé. ‘The space available can be an issue. Also whether you are overlooked or in a conservation area or a listed building. If the conservatory is overlooked, there are various glass options for privacy. Opaque, sandblasted, applied films, coloured interlayers, and glass that goes opaque at the flick of a switch.'

How can I regulate the temperature in my conservatory?

‘South-facing glass roofs get hot, and modern double glazing should have a UV filter to reduce solar gain,' says Jeremy Uglow, Managing Director, Glass Houses by Jeremy Uglow. ‘For how to make a conservatory warmer, underfloor heating is an option. On smaller areas - less than 20sq m - electrical systems are preferred. Wet underfloor systems suit larger areas, but these are harder to install.

'The following recommendations could help with temperature moderation,' advises David from Prime Oak. ' Use Solar Control Glass especially on south facing properties. Consider ventilation options, such as large roof vents. Finally, don’t design the room with too much glazing. To do this, use brick walls with windows in and dwarf walls to reduce the overall amount of glazing.'

Thea Babington-Stitt
Assistant Editor

Thea Babington-Stitt is the Assistant Editor for Ideal Home. Thea has been working across some of the UK’s leading interiors titles for nearly 10 years. 

She started working on these magazines and websites after graduating from City University London with a Masters in Magazine Journalism. Before moving to Ideal Home, Thea was News and Features Editor at Homes & Gardens, LivingEtc and Country Homes & Interiors.