Can I Turn My Conservatory into a Proper Extension?
Can I Turn My Conservatory into a Proper Extension? What You Need to Consider
Most of us find ourselves needing more space in our homes at some point in our lives, but it’s often not practical or affordable to move to a bigger property. So if you have an old conservatory that rarely gets used, you may have wondered whether you could turn it into a proper extension instead.
The good news is that, in many cases, you can! However, converting a conservatory into a fully insulated room that's integrated with the rest of your home isn't necessarily as straightforward as replacing the roof and adding some insulation.
There are several things to consider, including the existing foundations, Building Regulations, planning permission and, of course, the cost.
What's the Difference Between a Conservatory and an Extension?
The main difference is how the two structures are built and how they're connected to the house.
Traditional conservatories typically have large areas of glazing and glass or polycarbonate roofs, which can make them difficult to keep at a comfortable temperature. They're also usually separated from the main house by external-quality doors.
A proper extension, on the other hand, is designed to meet the Building Regulations that apply to habitable living spaces, including requirements for insulation, structural stability and ventilation.
This means it can be integrated with the rest of your home, allowing you to create a larger kitchen, dining room, lounge or other living space without having to keep the original dividing doors.
Are My Conservatory Foundations Suitable?
Many conservatories were built on relatively shallow foundations designed to support a lightweight glazed structure, rather than the additional weight of traditional brick walls and a tiled roof.
Before converting your conservatory, the foundations will need to be assessed to establish whether they're capable of supporting the proposed structure. This may involve excavating a small trial pit to inspect their depth, width and condition.
If the existing foundations aren't suitable, they may need to be strengthened or replaced, which can add considerably to the cost.
However, lightweight modular building systems can offer an alternative to traditional brick construction, potentially allowing existing foundations to be retained where they're assessed as suitable.
Can I Keep My Existing Conservatory Dwarf Walls?
If your conservatory has low brick walls beneath the windows, it may be possible to incorporate them into the new extension.
However, conservatory dwarf walls often lack the insulation and construction details required for a habitable room. They may need to be upgraded or replaced, depending on their condition and the proposed design.
In some cases, removing the existing conservatory structure and building new insulated walls on a suitable base may be more practical than trying to adapt everything that's already there.
Do I Need Planning Permission to Replace My Conservatory with an Extension?
Not necessarily.
In England, many single-storey extensions can be built under Permitted Development Rights, meaning you don't need to apply for full planning permission, provided the proposed extension meets the relevant conditions.
For example, the standard permitted development limits for single-storey rear extensions are generally:
- Up to 3 metres beyond the original rear wall for terraced and semi-detached houses.
- Up to 4 metres beyond the original rear wall for detached houses.
- A maximum overall height of 4 metres, with additional restrictions near boundaries.
Larger rear extensions may also be possible under the prior approval process.
However, these measurements are taken from the original house, not from the back of your existing conservatory.
There are also additional restrictions for certain properties, including listed buildings, homes in conservation areas and properties where permitted development rights have been removed.
Even if you're replacing your conservatory with an extension of exactly the same size, you shouldn't assume that planning permission won't be required.
It's always worth checking with your local planning authority before starting work. You may also wish to obtain a Lawful Development Certificate to confirm that your proposed extension is permitted development.
Will My New Extension Need to Meet Building Regulations?
Yes. This is one of the most important differences between an ordinary conservatory and a proper extension.
Many existing conservatories were exempt from most Building Regulations when they were constructed, provided they met certain conditions, including being separated from the main house.
However, converting one into a habitable extension means the new structure will need to comply with the relevant requirements.
These include:
- Structural stability: The foundations, walls and roof must safely support the building.
- Thermal efficiency: The walls, roof, floor, windows and doors must meet the applicable insulation and energy-efficiency requirements.
- Ventilation: Adequate ventilation must be provided to maintain air quality and help prevent condensation.
- Fire safety: The design must meet the relevant fire safety requirements.
- Drainage and electrical safety: Any new installations must comply with the applicable regulations.
Can I Remove the Doors Between My Conservatory and House?
One of the main reasons for converting a conservatory into an extension is to create an open-plan living space.
However, you can't simply remove the dividing doors from an ordinary conservatory and treat it as another room.
The doors often form part of the arrangement that allowed the conservatory to be exempt from Building Regulations. Removing them means the altered space must be assessed against the relevant requirements.
If you want to widen the opening or remove part of the external wall, structural calculations and suitable support, such as a steel beam, may also be necessary.
Can I Keep Large Windows and Glass Doors in My New Extension?
Yes, although there are limits to how much glazing can be incorporated without additional energy-efficiency calculations.
Under the usual approach to Part L of the Building Regulations, the area of windows, glazed doors and rooflights in a new extension is generally limited to 25% of its floor area, plus an allowance for any existing windows and doors that are removed or covered by the extension.
This doesn't mean you can't have larger windows, bifold doors or rooflights. It simply means that additional calculations and potentially improved insulation elsewhere may be needed to demonstrate compliance.
It's worth considering this at the design stage, particularly if you want to retain the bright, airy feel of your conservatory.
Is It Better to Convert a Conservatory or Knock It Down and Start Again?
This depends on the condition of your conservatory and what you want to achieve.
If the existing structure is sound and your main complaint is that the room is too hot or cold, replacing the roof with an insulated conservatory roof may be a more economical solution.
However, if you want to remove the dividing doors, change the layout or create a completely integrated living space, a full conversion or replacement is likely to be more appropriate.
Trying to adapt an older conservatory can sometimes prove expensive, particularly if the foundations, walls and floor all need substantial work.
Starting again also gives you greater freedom to choose the position of windows and doors, the roof design and the internal layout.
How Much Does It Cost to Turn a Conservatory into an Extension?
The cost can vary considerably depending on the size of the building, the construction method and how much of the existing structure can be reused.
The main expenses to consider include:
- Removing and disposing of the existing conservatory
- Any necessary foundation or groundwork improvements
- New insulated walls, roofing, windows and doors
- Structural work to open up the room to the main house
- Heating, electrics, flooring and internal finishing
- Architectural drawings, structural calculations and Building Regulations approval
- Planning applications, where required
Traditional brick-built extensions can be particularly expensive if the existing conservatory foundations aren't suitable, as new foundations and extensive construction work may be needed.
A lightweight modular system may help reduce some of these costs, particularly where the existing base can be retained.
Is It Easier to Convert a Conservatory Using a Modular System?
Traditionally, replacing a conservatory with a proper extension has often meant demolishing the existing structure and undertaking months of building work.
However, modern modular construction systems such as the Leka Xi offer a much quicker and less disruptive alternative.
The Leka Xi system uses lightweight, prefabricated GRP (Glass Reinforced Plastic) structural components, allowing a fully insulated extension to be constructed without the weight and extensive masonry work associated with traditional brick building.
The Leka XI system offers several advantages when replacing an existing conservatory.
- Lightweight Construction – Reduces the load on existing foundations, potentially allowing the original conservatory base to be reused.
- Excellent Thermal Efficiency – High-performance insulation helps keep the room comfortable all year round.
- Fast Installation with Less Disruption – Prefabricated components allow the structure to be assembled in just days, rather than weeks.
- More Usable Internal Space – Slimmer walls provide more internal floor space than traditional brick-and-block construction.
- Flexible Designs and Finishes – A choice of layouts, roof styles and external finishes to complement your home.
Find out more about the system and its benefits on our Leka XI Modular Extensions page.
Ready to Turn Your Conservatory into a Proper Extension?
If your existing conservatory has become an unused space, replacing it with a fully insulated extension could transform the way you use your home. And with lightweight modular systems such as the Leka Xi, the process may be much quicker and less disruptive than you think.
Here at Warm Roof Division, we can help you explore the options for replacing your conservatory with a practical, attractive living space that can be enjoyed all year round.
Visit our Leka XI Modular Extensions page for more information, or to get an instant online quote.