Glass extensions are a striking and modern extension project that has the potential to increase the value of your property, as well as provide you with a luxurious and upmarket living space that is great for hosting dinner parties or lounging in during the long summer evenings.
A stunning addition to your home, this type of feature also ranges in budget and design types, meaning it’s likely you will be able to source the type of glass extension you’re after at an affordable cost.
Our guide takes a closer at glass extensions, including how much they’re likely to cost, what affects the cost of building a glass extension, how you can save money and the best way to find a builder to instal your ideal glass extension.
How Much Does a Glass Extension Cost?
Unfortunately, glass extensions are not cheap to build, and you should be prepared for the project to be costly, even despite the potential measures you can take to keep the cost of the project down. This is because of the materials and labour involved in a glass extension – glass is not particularly cheap or easy to work with.
Typical costs, including supply and labour costs, are likely to range from £30,000-£75,000 depending on the size and design of the glass extension.
These costs can be much higher if the extension is very large, frameless, or if you decide to include additional design elements like bespoke lighting or a cantilevered roof.
|Type of Extension||Time Required||Total Estimated Cost|
|Standard glass extension||10-12 weeks||£1,350-£1,950 per square metre|
|Standard glass extension (London and South East)||10-12 weeks||£1,800-£2,300 per square metre|
|Glass side return extension||10-12 weeks||£2,000 per square metre|
|Full glass extension||10-12 weeks||£3,000 per square metre|
A standard glass extension is likely to cost £1,350-£1,950 per square metre and take between 10-12 weeks to complete. This is an extension without any additional design elements or features that could increase the final price.
A standard glass extension for a property in London will be more expensive than for a glass extension in other regions of the UK, as with all home renovation projects. This type of build is likely to cost between £1,800-£2,300 per square metre and it is estimated to take between 10-12 weeks to complete.
A glass side return extension is designed to slot into an unused area of your property and is a perfect design type for any property that doesn’t have a huge amount of space on offer for an extension. These practical extensions are likely to cost £2,000 per square metre and take between 10-12 weeks to complete.
A full glass extension is likely to be the most expensive option when it comes to designs of glass extensions, and this is due to the materials involved in the build. The average estimated cost for this will be around £3,000 per square metre and it will take 10-12 weeks to complete.
If you’re hoping to get started on a glass extension for your property, use HouseholdQuotes to quickly and easily compare quotes from reputable builders to help you find the perfect match for your glass extension project!
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What Affects the Cost of Building a Glass Extension?
Glass extensions are typically quite expensive builds, and some factors will make the job more expensive. We’ll take a look at what these factors are, so you know what’s likely to impact your final cost and can prepare to keep the design within your budget from the offset.
Size, as always, is going to play a big role in determining the final cost of the job. The larger you want your glass extension to be, the more materials will be involved in the build and the more labour will be needed to build it.
On average, a glass room extension cost is £40,000 but this can be much higher for a larger build, or a build that has additional features.
If you’re yearning for a space flooded with natural light to enjoy your garden but have limited space, consider a glass side return extension, which will cost you less and allow a glass extension to slot into a small space, instead of needing a large area to instal.
The average cost of a glass side extension is £2,000 per square metre.
Choice of Glazing
The key to a good glass extension is to make sure you’ve got all the finer details figured out before you go into the build. There is a whole range of different styles to choose from, and the details of an extension are what will make it perfect for you from the beginning as well as impact the final cost.
Glass extensions, by their nature, have many windows, so decide early on what kind of glazing you’re going to have installed with it.
Single or partly glazed windows will be less expensive than double glazed windows. Triple glazed windows will be the most expensive of all the options but offer the best quality for energy efficiency and noise reduction.
Glazed windows also may mean a lack of space in the new extension, so take into account practicality as well as cost when deciding which type of glazing to instal.
Choice of Doors
Similarly, you will need to think about how you want to be able to access the glass extension and what kind of style will work best for you in terms of aesthetics. The doors are an important feature of a glass extension as their design will need to fit with the build as a whole.
Many glass extensions have sliding doors, but there is an entire range to choose from including bi-fold and pivot as other options.
These types of doors will all be costed differently depending on the overall design of the extension, so make sure to speak to a range of builders to find the best quote for the style you’re after.
Choice of Roof
You will need to consider the roof of a glass extension as a part of the wider design. Again, you will have a range of options to consider but the most common will be to opt for a solid or glazed roof.
If you want a solid roof, you’re going to need to ensure that the structural support for the roof is included in the design of the extension.
Different types of roofs will be priced differently depending on the overall design of the extension and how much labour it will take to fit.
As you embark on beginning the work for a glass extension, it will become clear that where you are located in the UK will undoubtedly impact the final cost.
If you’re located in central London and the southeast, you can expect the prices for a glass extension to be pricier than for a property located in the Midlands, northern England, Wales, Scotland and Northern Ireland.
Prepare to account for the impact of your location on your final budget before you begin to hire any builders to start on the work.
Ease of Access
The builder or team you hire for the installation will need access to your property to instal the extension. If there is limited access to the side or back of your property, then a crane may have to be used to make sure the extension can go ahead.
This is because large panels of glass are very heavy and awkward to lift, so a labourer may not be able to get the right materials onto the property if access is limited.
Hiring a crane will increase the final cost of the project, and the price of hiring one could vary depending on the size of the crane and how long it is hired for. The builder or team you speak to will talk you through crane costs before the build begins.
Architect and Structural Engineering Fees
A structural engineer mainly focuses on looking at the weight of a building and what structural support is necessary to keep the building’s stability intact. They will specify what steel beams and other supporting elements may be needed for the project.
An architect, on the other hand, works closely with the homeowner to turn their dream development project into a reality. This means they will look at both the aesthetic design of a project and the structural side of it.
An estimated hourly fee to hire a structural engineer is between £100-£200.
An estimated hourly fee to hire an architect is between £150-£300.
Planning Permission and Building Regulations Approval
The cost of submitting a Building Regulation application can vary from £150-£300, whilst inspections can cost from £200-£650 depending on the regularity and number of inspections required.
These costs are separate from the costs of applying for planning permission, as planning permission is required for larger projects that are not covered by permitted development rights.
A planning application in England costs £206 and you should contact your local planning authority to find out their planning application fees if you are located in Wales, Scotland or Northern Ireland.
You should also be aware that planning permission application costs can and will increase depending on the size and nature of the project.
How Can I Save Money on a Glass Extension?
The best way you can save money on a glass extension is to plan carefully. Knowing the details of your project inside and out will help to minimise any mistakes that could be very expensive to fix.
Glass is typically cut to bespoke sizes when it comes to extensions, as it is an expensive and difficult material to work with, and if you haven’t planned extensively and need to make adjustments, it will be expensive to have this rectified.
A framed style is likely to cost less than a frameless style, as a frameless style will need to be made specifically and is going to be more complicated to work with than a framed style. This is a good choice of design that is very popular and gives a modern and clean-cut appearance to a glass extension.
One of the best ways to save money is to compare quotes from tradespeople to find the best deal for you. Use HouseholdQuotes to quickly and easily search for quotes from our reputable and vetted tradespeople!
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How Do I Find and Hire a Builder?
We always advise seeking recommendations from family, friends and neighbours who may have recently had a glass extension installed or know of someone who has.
Using recommendations from family, friends and neighbours can help you have peace of mind that about who you’re hiring and may even be able to see their work first-hand.
HouseholdQuotes offers you a quick and easy way to compare quotes from vetted builders, with the potential to save you 40% on your project quote. Use our website to search for the right builder for your glass extension.
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Ensuring the Professional Is the Right Fit
It’s a good idea to make sure you have a list of questions ready to verify that the professional you are hoping to hire is the right fit for you.
- Ask them for a written quote. Most contractors will be more than happy to provide a written quote and this way you can see exactly what you will be paying for.
- Ask for their experience. Glass installations are not easy to instal and you need to make sure you hire a builder who has the right experience.
- For their references. If they can provide you with references you can be sure of their ability and may even be able to see some of their previous work.
- For any photos of their previous jobs. This will offer you the opportunity to see the quality of their work and could also provide you with some good references for your own project designs.
- If they and their tools are insured. This can protect you from lawsuits if they or your property is damaged when they come to your home.
Use this checklist to make sure you’ve got a good idea of the necessary steps to take when hiring a builder for a glass extension.
- Plan your glass extension carefully.
- Decide what type of windows, doors and roof you want to be installed and budget accordingly.
- Use HouseholdQuotes and let us help you find a professional builder.
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Frequently Asked Questions:
Will I Need Planning Permission or Building Regulations Approval for a Glass Extension?
There are a series of requirements that must be met for an extension to be built, and you can read more about these requirements, here.
Should I Choose Double or Triple Glazing?
Double glazing refers to a window with two panes of glass whereas triple glazing has three panes of glass.
Triple glazing a window serves to be very energy efficient as well as achieving superior noise reduction. However, triple glazing can be tricky to instal and if not done in a specific manner could cancel out the benefits of the material.
Triple glazing is also more expensive than double glazing, with the price varying depending on the size and style of the window.
Double glazing is a cheaper option and may seem like it’s less beneficial than triple glazing, but this isn’t necessarily the case. A specialist will be able to let you know how double glazing can be installed to be as effective as triple glazing at a cheaper price.
What Are Some Alternatives to Glass Extensions?
Check out HouseholdQuotes’ guide to extensions to get a better idea of what type of extensions are on the market and their typical estimated costs.
If you’re interested in installing a conservatory and want to know a little bit more about their installation prices and benefits, HouseholdQuotes has a useful guide you can read here, on the average costs of a conservatory so you can compare the two and find out which is likely to work best on your property.
If you’re looking for a bit more living space but are hoping to minimise the structural changes involved in your property, a garage conversion might the perfect alternative for you. We’ve compiled a handy guide on garage conversions, that walks you through the estimated cost of installation as well as any additional costs you may need to be aware of before the project begins.