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House extension with bi-fold doors and garden access

Conservatory Extensions: Are Modern Conservatories Worth Considering Again?

Modern conservatories have moved a long way beyond the cold and uncomfortable garden rooms of the past

For many homeowners, the word conservatory still brings back memories of the structures added to houses throughout the 1980s, 1990s and early 2000s.

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They often looked attractive when they were first installed. They promised additional living space, better garden views and an abundance of natural light.

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Unfortunately, many did not perform particularly well.

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During the summer, the room could become unbearably hot. During the winter, it could feel cold and expensive to heat.

 

Condensation, failed double-glazed panels, ageing plastic frames and poorly specified roofs added to the problem.

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As a result, conservatories developed a poor reputation.

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We routinely visit homes where an older conservatory is rarely used and the homeowner is considering demolishing it to make way for a conventional rear extension.

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However, the story is beginning to change.

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Modern conservatory extensions are considerably better than many of the structures built a generation ago. Better glazing, improved frames, solar-control glass, more effective ventilation and a wider choice of roof systems have created a new generation of bright, practical garden rooms.

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For homeowners who want additional space without committing to the cost and disruption of a full brick-built extension, a well-designed conservatory extension is worth considering again.

Why did older conservatories perform so badly?

 

Older conservatories were often sold as a relatively inexpensive way to add another room to the house.

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The problem was that the emphasis was frequently placed on speed and price rather than long-term comfort.

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A typical conservatory included a large amount of glazing, lightweight frames and a glazed or polycarbonate roof. Many of the double-glazed panels offered limited thermal performance compared with the products available today.

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The glazing units could also fail over time. Once the seals deteriorated, moisture entered the cavity between the panes and the units became misted or cloudy.

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A heavily glazed room will always need careful specification because glass behaves differently from an insulated brick wall. If the roof, window panels, frames and ventilation are poorly designed, the room can quickly become uncomfortable.

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That is why older conservatories often became too hot in summer and too cold in winter.

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The underlying idea was not necessarily wrong. The materials and specifications were simply not good enough.

Why are modern conservatories better?

The modern conservatory has evolved.

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The biggest improvement is the quality of the building envelope: the glass, frames, seals, roof system and junctions between the components.

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A modern conservatory can include:

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  • High-performance double or triple glazing;

  • Argon-filled insulating glass units;

  • Low-emissivity glass coatings;

  • Solar-control glass to reduce overheating;

  • Warm-edge spacer bars to reduce heat loss around the edges of the glazing;

  • Better-insulated aluminium, timber or PVC-U frames;

  • Improved ventilation and opening rooflights;

  • Underfloor heating or carefully planned heating systems;

  • A glazed, hybrid or lightweight tiled roof.

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These improvements can make an enormous difference.

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A properly specified conservatory should no longer be viewed as a room that can only be enjoyed during a few mild weeks each year. It can become a useful dining room, sitting room, garden room, home office or entertaining space.

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However, the quality of the specification still matters. A cheap conservatory selected purely on price may recreate the problems of the past.

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The importance of argon-filled glazing

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Modern double-glazed panels are normally manufactured as sealed insulating glass units.

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The cavity between the panes can be filled with an inert gas such as argon. Argon is commonly used because it offers a sensible balance between thermal improvement and affordability.

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It helps reduce the transfer of heat through the glass, improving comfort during colder weather.

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However, argon gas should not be treated as a magic ingredient.

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The overall performance of the glazing also depends on:

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  • The type and thickness of the glass;

  • The width of the cavity between the panes;

  • The quality of the edge seals;

  • The use of low-emissivity coatings;

  • The spacer-bar design;

  • The frame construction;

  • The amount and orientation of the glazing.

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A good supplier should provide clear technical information rather than simply saying that the units are double glazed.

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Ask for the U-value of the glazing system. The lower the U-value, the better the thermal insulation.

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What about krypton and xenon gas?

 

Krypton can provide improved thermal performance, particularly where the cavity between the panes is narrower.

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It is considerably more expensive than argon and is therefore usually reserved for higher-performance glazing systems or situations where the available space is limited.

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Xenon is another specialist option, but it is rarely the practical choice for a normal domestic conservatory. The cost is generally difficult to justify.

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For most homeowners, a well-designed argon-filled unit with good low-emissivity coatings, solar-control properties and quality frames will provide the best overall balance.

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The sensible approach is to improve the complete system rather than paying a premium for one isolated component.

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Do not ignore summer overheating

 

Winter heat loss is only half of the equation.

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A conservatory contains a large amount of glass, which means solar gain needs to be considered carefully. This is particularly important for south-facing and west-facing gardens.

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A bright room is attractive. A room that becomes uncomfortably hot during sunny weather is not.

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Solar-control glass can help reduce the amount of heat entering through the glazing while still allowing plenty of natural light into the room.

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Depending on the orientation and design, it may also be worth considering:

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  • Opening roof vents;

  • High-level ventilation;

  • Side windows that can be opened;

  • External shading;

  • Internal blinds;

  • Carefully positioned planting;

  • A partially solid or tiled roof.

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A good conservatory should be designed for the specific house and garden rather than selected from a catalogue without considering orientation.

Glass roof, tiled roof or hybrid roof?

 

The roof has a major impact on the appearance and performance of a conservatory extension.

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Fully glazed roof

 

A glazed roof creates the lightest and most traditional conservatory appearance.

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This can work very well where the glass specification is carefully selected and the room has suitable ventilation. It delivers a strong connection with the sky and garden.

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However, a fully glazed roof needs proper solar control. This is not the place to choose the cheapest available product.

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Lightweight tiled roof

 

A lightweight tiled roof can create a more controlled internal environment.

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This option is useful where the homeowner likes the idea of a conservatory but does not want an entirely glazed roof.

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Lightweight tiles, including slate-style products, can provide a more solid appearance while keeping the roof structure relatively light.

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The inside can be insulated and plastered to create a more conventional ceiling. Carefully positioned rooflights can still bring natural light into the room.

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This approach can be particularly useful when upgrading an older conservatory that is structurally sound but thermally uncomfortable.

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Hybrid roof

 

A hybrid roof combines solid insulated sections with selected areas of glazing.

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For many homeowners, this provides the best compromise. The room remains bright, but there is more control over temperature, lighting, insulation and the internal appearance.

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A hybrid design can also provide ceiling areas for recessed lighting, speakers and decorative fittings.

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Conservatory extension or brick-built extension?

 

A conservatory extension and a conventional rear extension do not offer exactly the same thing.

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A brick-built extension is usually the better option where the objective is to create a fully integrated kitchen-diner, remove most of the rear wall of the house or maximise flexibility for everyday living.

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It provides more solid wall space for kitchen units, artwork, radiators, television screens and storage. It will generally feel more like a permanent part of the house.

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A conservatory extension offers a different set of advantages.

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It can provide:

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  • More natural light;

  • Better garden views;

  • A faster and less disruptive build;

  • A lighter architectural appearance;

  • A potentially lower project cost;

  • A beautiful space for dining, relaxing or entertaining.

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A conservatory will usually cost less than a fully integrated brick-built extension, but the saving depends heavily on the size, foundations, glazing, roof, frames and interior specification.

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For a simple project, the difference can be substantial. For a large bespoke hardwood or aluminium conservatory with premium glazing and high-quality finishes, the cost gap may be much smaller.

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The right comparison is not simply cheap conservatory versus expensive extension. It is whether the proposed room is suitable for the way you intend to use it.

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Faster construction with less disruption

 

A modern conservatory extension will often be quicker to build than a traditional extension.

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The foundations, base and drainage still need to be considered carefully, but much of the structure can be manufactured off-site and assembled efficiently once the groundworks are complete.

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This can reduce disruption, particularly where the homeowner is trying to avoid a long building programme.

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However, speed should never come at the expense of quality.

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The foundations need to be suitable for the ground conditions. The drainage needs to be reviewed. The frame needs to be properly fixed. The roof junctions need to be weathered correctly. The glazing units need to be specified for their position and orientation.

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A conservatory is a relatively lightweight structure, but it is still an extension to your home.

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Planning permission and Building Regulations

 

A conservatory falls under the same planning rules as another house extension.

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Some conservatories can be built under permitted development rights, subject to the normal limits and conditions. Others will require a householder planning application.

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Additional care is needed where the property is:

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  • Listed;

  • Locally listed;

  • Within a conservation area;

  • A flat or maisonette;

  • Subject to an Article 4 Direction;

  • A new-build home with restricted permitted development rights;

  • Already extended.

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The Building Regulations position also needs to be considered carefully.

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A conservatory may qualify for an exemption in certain circumstances, particularly where it is built at ground level, remains below the relevant size threshold, has suitable glazing and electrical installations, and is separated from the main house by external-quality doors, windows or walls.

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If the dividing doors are removed and the conservatory is opened fully into the house, it may lose that exempt status. The project will then need to be assessed as an integrated extension, including its thermal performance, ventilation and structural alterations.

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This distinction is important.

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A homeowner may understandably want a seamless open-plan room. However, a fully integrated glazed extension needs to be designed properly from the outset.

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Replacing an old conservatory

 

Where an older conservatory is uncomfortable, tired or leaking, there are three main options.

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Upgrade the glazing and frames

 

This may be worthwhile where the base, foundations and overall structure remain sound.

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New sealed glazing units, better doors and improved frames can make a noticeable difference.

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Replace the roof

 

A lightweight tiled or hybrid roof can transform the usability of an existing conservatory.

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This is particularly useful where the room overheats through the roof or feels uncomfortably cold during winter.

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Demolish and rebuild

 

Sometimes the best answer is to start again.

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We regularly see older conservatories with shallow foundations, poor proportions, failed panels and awkward connections to the house. In these cases, spending money on isolated improvements may not produce a satisfactory result.

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A new conservatory extension or a conventional brick-built extension may offer much better long-term value.

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Design the conservatory to suit the house

 

A conservatory should not look like an afterthought.

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The most successful examples respond to the style, scale and proportions of the original property.

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A traditional detached or semi-detached home may suit a painted timber conservatory with fine glazing bars, a pitched roof and elegant French doors.

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A more contemporary house may suit slim aluminium frames, larger panes of glass and a simpler roofline.

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The patio and landscaping also matter. A proper stone terrace, carefully chosen planting and a clear route into the garden will help the extension feel like part of a wider design.

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The conservatory should enhance both the house and the garden.

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Is a conservatory extension right for your home?

 

A modern conservatory extension may be worth considering where:

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  • You want a bright garden-facing room;

  • You value natural light and outdoor views;

  • You need additional dining, sitting or entertaining space;

  • You want a faster build than a conventional extension;

  • You are looking for a more cost-effective way to add useful floor area;

  • You are prepared to invest in good glazing and a suitable roof system.

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A conventional extension may still be the better answer where:

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  • You want a large open-plan kitchen;

  • You need extensive wall space and storage;

  • The room will become the main everyday family space;

  • The garden orientation creates a significant overheating risk;

  • You want the addition to feel completely integrated with the existing house.

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There is no single correct answer.

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The important thing is to make an informed decision before committing to the project.

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A modern solution to an old problem

 

Older conservatories earned their poor reputation for understandable reasons.

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Many were uncomfortable, poorly insulated and difficult to use throughout the year.

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But the technology has moved forward.

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With high-performance glazing, argon-filled sealed units, improved frames, solar-control glass and a suitable roof design, a modern conservatory extension can provide an attractive and practical addition to the home.

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Done properly, it can deliver the natural light and garden connection homeowners want, without necessarily carrying the cost or disruption of a full brick-built extension.

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Architectural Partner Network (APN) can help homeowners explore the options and connect with suitable professionals for the design, planning and construction stages of a conservatory extension project.

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Tell Us About Your Conservatory Extension

 

Considering a new conservatory extension or looking to replace an older structure?

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Tell us a little about your property, your existing layout and the type of room you would like to create. We can help you understand the next steps and, where appropriate, introduce you to suitable extension professionals.

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