Conservatory planning permission 101 – and how to plan your space

Whether you’re in the midst of adding an extension to your home or are thinking about potentially amending an existing conservatory, there are quite a few things that you will need to consider before you get started. And ensuring that you are aware of all the regulations and necessary permissions will save you from encountering any issues down the line.

When it comes to how to plan and create your dream conservatory, you don’t want to skimp on the details only for it to come back to bite you later on, such as when you go to sell your home.

You’ll also need to think about how you plan on using your conservatory. If you’re simply looking to add extra square footage and a place to sit out and enjoy some indoor-outdoor living, this will differ to say turning your conservatory into an additional bedroom. And once you’ve built your conservatory you may be thinking about altering it slightly to get the most out of it. For example, you might want to put a solid roof on it or change its purpose after a few years.

Conservatory planning permission

Keep reading to find out everything you might need to know when it comes to how to plan a conservatory. How many of these questions have you already considered?

What is a conservatory?

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?

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.

What makes a conservatory not an extension?

‘A conservatory differs from an extension primarily in its structure and purpose. While a conservatory functions as an indoor-outdoor space with glass walls and a transparent roof, extensions are typically integrated into the existing structure of the house itself, featuring solid walls and a traditional roof,’ admits Geoffrey White, Managing Director at GLW Engineering.

In most cases, conservatories that adhere to specific size and design limitations can be built under permitted development rights, meaning you don't need full planning permission. Extensions, on the other hand, typically require some kind of formal planning application.

Do you need planning permission for a conservatory?

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 of 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?

'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 you'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.'

Can I convert my conservatory into an extension without planning permission?

According to the experts, converting a conservatory into a fully functioning extension may involve changes beyond permitted development regulations. And because of this, it is wise to check with the planning department at your local authority to be completely sure before you start the process of converting your conservatory into an extension.

For example, if you live in a conservation area or area of natural beauty, you will definitely need to consult your local planning department.

But ‘the most important aspect of converting a conservatory into an extension is the difference in the weight of the structure,’ explains Ryan McDonough, interior design expert at MyJobQuote.co.uk.

‘An extension will be much heavier than a conservatory and the footings or foundation system installed may not be sufficient to bear the extra weight. You must get the depth of the foundations checked by a structural engineer before starting any work on converting your conservatory.’ This information will then need to be passed on to the building control inspector.

Do I need permission to put a solid roof on my conservatory?

Unfortunately quite a lot of heat and energy can be lost through a traditional glass or UPVC conservatory roof, which can make it tricky to enjoy time out in your conservatory all year round. It can become swelteringly hot during the summer and icy cold in the winter. You might also find that when it rains heavily the sound can become rather deafening. And both of these reasons might have led you to think about replacing your existing conservatory roof with a solid one.

‘If you gained planning permission for the existing conservatory and now seek for it to have a solid roof, providing it is of the same height, it is unlikely to require planning permission,’ according to Melanie Clear, founder of Clear Architects. ‘If, however, the new roof is higher, even by the smallest of measurements, this will require planning permission.’

But, ‘given the thermal improvements this will make to the overall home, most councils will be accepting of this change to help reduce energy use for the property,’ Melanie asserts.

While Steve Rawding, sales director at SEH BAC says, ‘adding a solid roof to your conservatory might fall under permitted development, depending on factors like the size of your conservatory, its location on your property, and the materials used. It will however require building regulations as solid roofs are regulated structures.’ So, this is something you’ll need to consider before making any changes.

Do I need a door between a house and conservatory?

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.'

Distance to boundaries

‘The permitted development regulations for conservatories state that a conservatory can be built no closer than two metres to a boundary if the eaves (the overhanging part of the roof) are higher than three metres,’ Steve maintains.

‘If the eaves are lower than three metres, the conservatory can be built right up to the boundary,’ he continues. But if you do plan on building right up to the boundary, you might still need to consider The Party Wall Act 1996, which will require you to let your neighbour know in advance and get their agreement before any work begins.

What are the building regulations?

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.

Can a conservatory have a solid brick wall?

‘Conservatories do normally have a small wall to build the conservatory structure from, though most conservatories would likely only have 20% built wall structure,’ Melanie admits. But if it is made up of mainly solid walls, this would most likely be classed as an extension, instead of a conservatory.

However, many conservatories incorporate solid brick walls alongside glazed sections as they can offer additional privacy and improve thermal insulation, with Ryan arguing that ‘brick walls offer many benefits including better insulation, durability and a more unified look with the rest of the property.’

What materials can you use?

'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 of 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 conservatory on the front of my house?

'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.'

Can I fit a conservatory in a courtyard garden?

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 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 of 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.

Selecting an architect

‘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 of 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.'