Homeowners who want a larger house but without the expense or difficulty of moving are often faced with a choice: should they choose an extension, or should they opt for a conservatory?

In this post we will look at some pros and cons of both and then say why we think a middle ground that offers the best of both might be the best way to proceed.

Conservatory vs Extension: Head to Head

conservatory v extension


A conservatory will cost significantly less than an extension. If a homeowner was looking to add some extra square footage by the cheapest method possible, then a conservatory would win every time.

An extension will potentially cost many times the amount that would be required to have a conservatory fitted. Is the extra expense worth it?

Planning Process

A conservatory will not always require building regulations. This depends on several factors including its size in isolation and also relative to the overall size of the house.

Even when building regs are required, this will typically be a simple process, one that will not add undue delay to the construction.

Extensions are a different matter. The extension might require planning permission and building regulations approval is also likely to be necessary. There might be plans to be drawn and submitted and then possible revisions to be made – all this creating delay and adding to the expense.

In many cases, having an extension built is a process that runs smoothly, with building regs approval quickly granted and the work sticking to deadline and cost. However, the added complications compared to a conservatory make delay and additional expense in the planning process more likely.


A good extension should pay for itself, and hopefully more, should the homeowner ever look to sell. The money spent in having it built transferring into an increased property value that is at least commensurate. 

Conservatories, at least those with glass and polycarbonate roofs, are less certain to add value, many would-be buyers are likely to see them as a problem rather than a desirable space.


Traditionally, this has been where extensions have justified their increased cost. They might come with a hefty price tag, but they create a space that is superb all year round and suitable for any imaginable use.

Conservatories, on the other hand, have been seen to create space that is often of little use. Conservatories with glass or polycarbonate roofs are too hot in the summer and too cold in winter, simply amplifying the prevailing conditions. Rather than being superb usable space, they are often used instead as expensive, extra storage.

Which to choose

Until the last few years, the choice has boiled down to whether the homeowner has been able to afford an extension.

Those that could afford extensions chose that option, others who were determined to get the extra space regardless of the concerns about the usability of the space opted for a conservatory.

Those going for the second option ended up disappointed, paying for a product that created no real benefit. It could be argued that conservatories with glass or polycarbonate roofs are a purchase that should always be avoided – better to keep money for another use than use it to create a conservatory that will rarely get used.

However, there is a third way…

Conservatory v Extension: The best of both worlds

The old saying that you can’t have your cake and eat it need not apply to those looking for a superb usable space but without the cost of an extension.

Since 2010, it has been permissible to have a conservatory with a lightweight, solid roof rather than the unsuitable glass or polycarbonate roofs that had a duopoly on the market previously.

This one regulatory change has had a profound effect, a homeowner can now get a superb usable space for a fee more in line with that of a conservatory. The lightweight roofs sit on a conservatory structure and can be fitted either on to a new build conservatory or as a replacement to any pre-existing conservatory roof.

At PCL, we install the market-leading SupaLite conservatory roof system. These roofs have a superb U-value of 0.18, this means that they are superb at keeping the room at a pleasant ambient temperature. They also lead to greatly reduced heating bills, typically saving the homeowner around £200 per winter.

The SupaLite system, which has full building controls approval and always comes with a lengthy guarantee on both parts and workmanship, is also available in a wide range of styles and subtle colours. The tiles update the look of the conservatory, no longer will it look like a glass or polycarbonate bolt-on, instead it has the look of a sympathetic extension.

The SupaLite system enables a homeowner to get the additional space they wanted at a price that is affordable and also for it to be usable space. That key final part, that the space was usable, rather got forgotten in the rush to add glass and polycarbonate conservatories in the 1980s.

There is a wealth of information on this site – please do have a look around and contact us with any queries. Call us on 0800 031 5444 or use our Contact Form. 

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