Orangeries And Conservatories: Everything You Need To Know About Specifying A Glazed Extension

Founded in 1982, Hampton Conservatories is a leading designer and manufacturer of bespoke hardwood glass buildings. With a wealth of expertise in producing conservatories, orangeries, swimming pool enclosures, botanical glasshouses, garden rooms and glazed pavilions, the UK-based company has clients across the globe and their award-winning projects feature as extensions on many prestigious buildings. Here, Mervyn Montgomery, founder and joint director shares everything you need to know about choosing and specifying a glazed extension.

What’s the difference between an orangery and a conservatory?

The key differentiator is the roof, which on a conservatory tends to be sloping. The legal definition is a structure where three quarters of the roof and half of the external walls are constructed from a translucent material. Conservatories also bear their weight onto their side frames and are generally very light and bright. On the other hand, orangeries have a suspended glazed ‘lantern’ supported by an internal steel structure, which is built into a flat roof. This adds height and space and allows natural light to flood the room below. The flat areas of an orangery’s roof provide shade in the summer and additional warmth in winter as they are heavily insulated.

Image name: HC - Orangery 39This double glass roof lantern orangery adds grandeur, height and additional space to this generous and bright living room.
Image: This double roof lantern orangery adds grandeur and height.

What type of property does each style work best with?

Orangeries work well on most homes and are increasingly becoming more popular than conservatories due to their year-round serviceability and because their lower roofline makes them easier to attach to different properties. They suit period and listed buildings where architectural symmetry is important and also work well when existing bi-fold doors were previously used to access the outside space. Conservatories are ideal for a less sunny side of a property, and sometimes a local planning department will insist on an extension being a traditional conservatory.

Image name: Cornice EntablatureA close up of an orangery entablature, an architectural design detail, one of the design options which would compliment a more traditional home aesthetic.
Image: Close up of an orangery entablature.

Why are they so popular with period property and listed property owners?

Gaining planning consent for an extension on a period or listed property is not always without its complications. Most local planning authorities quite rightly regard owners as custodians of historically significant buildings and are reluctant to sign off anything incongruous with its period or style. Both orangeries and conservatories are looked upon more favourably as they can be designed to take into account classic proportions and ratios, ensuring they remain in keeping with the original building. In addition, older buildings typically have smaller rooms. When adding a glazed extension, the external wall is often removed. This creates a larger, more free-flowing space better suited to the way we use our homes today.

Image name: HC - Conservatory 19This conservatory adds classical proportions and balance to the original house. Argan-filled glass improves energy efficiency and thermal performance, reducing heat loss through the glass doors.
Image: This conservatory adds classical proportions and balance to the existing property.

Can they work on contemporary buildings too?

Orangeries and conservatories can work equally well on contemporary properties but tend to be designed with fewer traditional or ornate features.

How easy is it to get planning consent for a glazed extension?  

As a general rule, smaller orangeries or conservatories don’t require planning permission because they fall under permitted development rights. The maximum depth under permitted development for a single-storey rear extension is eight metres for a detached house and six metres for an attached house, with a maximum height of four metres. If you wish to extend further, you will need to apply for planning permission via your local planning authority.

Some local authorities have a dedicated officer who is responsible for period and listed homes or those within specific conservation areas. A reputable designer will have experience gaining planning consent and can support you throughout the application process. Typically, for a Hampton Conservatories glazed extension, the timeline from planning approval to installation is between 16 to 26 weeks.

Image name: HC - Orangery 8This spectacular orangery seamlessly blends indoor and outdoor living, a great way of adding internal floor area and creating new living space with glass panels and design in keeping with the main house, unlike a frameless design which would be more of a contrast.
Image: This spectacular orangery seamlessly blends indoor and outdoor living.

What do you need to consider if you’re thinking about investing?

Heating and ventilation are the main considerations, and requirements will vary depending on positioning, whether the new space is knocked through to other rooms and the amount and quality of glazing involved. For example, north-facing extensions will require more heating as well as argon-filled window cavities, which improve durability and insulation.

Technological developments mean that glass can be tinted or coated to reduce glare and similarly, glass can be specified to reduce the amount of heat that the extension absorbs from the sun.  G-value is a scale that measures the sun’s transfer directly through glass, plus the heat it absorbs and radiates into the room. As rule, low G-value glass would be specified in a south-facing roof, while for a north-facing roof a higher G-value may be more appropriate.

One of the most effective methods of cooling a conservatory is to install adequate roof vents that create a flow of air through the space and enable warmer air to escape as it rises. You can also specify automated, electric roof vents with thermostatic control and rain sensors, which open when the weather is warm and dry, and close when they sense rain.

How does the design process work?

In many cases, a conservatory or orangery may be part of a larger property overhaul and the designer will work directly with the architect or project manager overseeing the renovation, although they can of course work directly with homeowners too. An initial consultation will take into account your specific needs and proposed use, as well as statutory consents (planning permission), budget, process, logistics and timing.

What are the options in terms of colour/finish?

At Hampton Conservatories we offer 36 traditional and heritage colours for internal and external woodwork. These range from bright whites through to subtle greens and greys and bolder off-black shades. Unless it’s a condition of planning consent there are no rules, so you can either choose a colour that helps the extension blend seamlessly with the existing building or opt for a contrasting shade to make more of a statement.

Image name: HC - Orangery 36Orangeries and conservatories don't have to painted white - go bold with a shade such as of off-black, as shown in this example of an open-plan kitchen area. A fantastic way to add character and a modern style to the extra space created by the home extension.
Image: Orangeries and conservatories don’t have to painted white – go bold with a shade such as of off-black.

What kind of maintenance do glazed extensions require?

While the painted finish on timber can last from 5 to 8 years before re-painting, regular maintenance – washing with a mild soap and water at least twice a year, and more in areas of higher pollution or near the coast – is essential, as is checking for blocked gutters and downpipes. When temperatures fall, blockages and frozen water will expand and potentially cause damage. Powder-coated roof cappings and finials will also benefit from a bi-annual dust and wash down with mild detergent to ensure they remain pristine and functional. Maintenance of the frame and glass can usually be undertaken by a window cleaner, but pressure washers aren’t advised as they can damage seals and coatings and cause water ingress.

Orangeries and conservatories are usually seen as spring/summer spaces, but how can you make them work at other times of the year?

Many homeowners who invest in glazed rooms comment on how they feel more connected to the changing seasons than they did before they added their extensions. It’s a good idea to consider installing a fireplace, stove or log burner to make things feel cosier if you want to use the space in the cooler months. This creates a focal point and will of course provide additional warmth.

Image name: HC - Conservatory - 15Not just for summer and warmer weather, an orangery or conservatory can be enjoyed in the cooler months or at Christmas too, maintaining a comfortable temperature all year round with the right building materials high levels of thermal efficiency can be achieved.
Image: Not just for summer, an orangery or conservatory can be enjoyed in the cooler months or at Christmas too.

If you have been thinking about specifying a glazed extension and have any questions or would like a quote, please contact the experts at Hampton Conservatories:

We hope you have enjoyed reading about orangeries and conservatories, and have found valuable advice and inspiration for your own glazed extension projects. Please share this blog with a friend who might also find it useful. You can also read our other interior design blogs for more insights from the experts on your favourite topics, such as modern kitchen design ideas, how to light art or home office essentials.

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