A house extension is one of the best ways to create more space without moving home. Whether you’re planning a kitchen extension, creating an extra bedroom, adding a utility room or transforming your existing home with a larger living area, choosing the right extension builders is essential.
The best house extension company UK homeowners choose will have extensive experience, excellent communication, a skilled build team and a proven ability to deliver projects on time and within budget. From single storey extensions to double storey extensions, loft conversions and complete house renovation projects, selecting the right build company can make the entire process far less stressful.
If you’re planning a project in Scotland, working with a specialist Glasgow house extensions company gives you access to local knowledge, experienced professionals and guidance on planning permission and building regulations.
What Makes a Great House Extension Company?
Not every builder specialises in home extensions. While many contractors carry out general building work, experienced extension builders understand the structural work involved when altering an existing home and can overcome issues before they become expensive delays.
A reputable company should offer:
- Extensive experience delivering house extension projects
- A dedicated project manager
- Full project management from design through to completion
- Fixed-price quotations
- Public and employer’s liability insurance
- Positive Google reviews
- A portfolio of completed projects
- Warranty options for added peace of mind
Many homeowners now choose a full design-and-build service because one company manages everything from initial drawings and structural calculations through to planning permission, construction and final handover. This simplifies communication and keeps the project moving efficiently.
Popular House Extension Options
Every property is different, which is why there are several house extension options available depending on your budget, available space and long-term plans.
Single Storey Extensions
Single storey extensions remain one of the most popular choices across the UK.
A single storey rear extension can completely transform the rear house by creating a spacious open-plan kitchen extension, dining area or family room. Many homeowners choose this option to gain more living space without moving home.
Many single storey extensions can be built under permitted development rights, although this depends on the size and location of the extension.
Double Storey Extensions
Double storey extensions provide excellent value by increasing floor space across two levels.
A double storey extension can enlarge the kitchen downstairs while creating an extra bedroom and additional bathroom upstairs. Double storey extensions are particularly attractive for a growing family looking to maximise space without sacrificing too much garden.
Although they involve a larger investment, two storey extensions often provide a better return than extending only the ground floor.
Rear Extensions
Rear extensions are one of the most common forms of home improvements.
A rear house extension creates valuable new space while allowing large glazed doors and rooflights to introduce more natural light into the property. Rear extensions are suitable for everything from kitchen extensions to family rooms and open-plan living areas.
Many rear extensions can also improve the overall property value.
Side Return Extension
A side return extension makes use of the narrow passage found beside many Victorian and Edwardian homes.
Return extensions are especially popular for house extensions in London where outdoor space is limited. A side return extension can significantly enlarge a kitchen while improving the layout of the entire ground floor.
Wraparound Extensions
Wraparound extensions combine rear and side extensions to create one large extension.
These return house extension designs maximise space while creating flexible layouts with excellent natural light. They are becoming increasingly popular for larger family homes.
Ground Floor Extension
A ground floor extension offers flexibility for homeowners who need more usable space.
Whether it’s a utility room, home office, playroom or larger lounge, extending the ground floor often improves everyday life while making the property more attractive to future buyers.
Loft Conversions
Loft conversions continue to be one of the most practical ways to create an extra bedroom without increasing the footprint of the house.
Many extension in London projects combine loft conversions with rear extensions to maximise every available square metre.
Garage Conversions
Garage conversions are another practical option for creating new space. They work particularly well alongside a house extension project or complete renovation, allowing homeowners to create offices, gyms or guest accommodation.
Understanding House Extension Cost
House extension cost depends on several factors including size, specification, location and complexity.
As a general guide:
- A single storey rear extension usually costs between £40,000 and £80,000
- Double storey extensions generally cost £70,000 to £150,000
- A side return extension typically costs £35,000 to £65,000
Costs vary depending on the design, structural requirements and the overall size measured by square metre.
When budgeting, don’t forget that extension cost isn’t limited to the main construction work. Additional cost items often include:
- Planning and engineering fees of around £1,900 to £3,200
- Structural calculations
- Building Control fees
- Drainage alterations
- Landscaping following completion
House extensions are also generally subject to 20% VAT, so this should be included when calculating your total budget to avoid hidden costs later in the project.
Planning Permission and Permitted Development
Planning permission is one of the first things homeowners consider before starting building work.
Fortunately, many single storey extensions fall within permitted development rules, meaning a formal planning application may not be necessary.
However, planning approval is normally required if an extension exceeds permitted development limits, is located within a conservation area or involves more complex designs.
Obtaining a Lawful Development Certificate can provide reassurance that permitted development rights apply.
Planning requirements also vary between local authorities, particularly for house extensions in London, so it’s important to work with professionals who understand local regulations.
If neighbouring properties could be affected, party wall agreements may also be required before construction begins.
A reputable build company should explain planning permission, building regulations and the entire process before work starts.
House Extension Companies Worth Considering
Several companies have built strong reputations for delivering high-quality home extensions across the UK.
Examples include:
- Designer Garden Rooms
- Resi
- Plus Rooms
- Extendahome
- Simply Extend
- Absolute Lofts
- Touchstone Lofts
- Baufritz UK
These companies offer a comprehensive range of services including bespoke house extensions, loft conversions, rear and side extensions, wraparound extensions and complete renovation projects.
Rather than choosing purely on price, compare each company’s experience, completed projects, communication, warranties and customer feedback.
How to Choose the Right Extension Builders
A home extension project is a big project, so taking time to research builders can save money and reduce stress.
Before appointing a contractor, you should:
- Obtain at least three detailed written quotes.
- Confirm the builder has public and employer’s liability insurance.
- Ask about memberships with organisations such as the Federation of Master Builders (FMB) or National Federation of Builders (NFB).
- Review previous extension projects.
- Read Google reviews.
- Seek personal recommendations where possible.
- Check how many years the business has been operating.
- Ask whether a dedicated project manager will oversee your build.
- Confirm whether the quotation is fixed price.
- Check what warranty is included after completion.
The best extension builders also maintain excellent communication, keep sites tidy, minimise disruption and work proactively to overcome issues before they become expensive problems.
Conclusion
Whether you’re planning a kitchen extension, rear extensions, wraparound extensions, loft conversions or a complete house renovation, choosing experienced home extension specialists is one of the most important decisions you’ll make.
The best companies combine quality workmanship, strong project management and transparent pricing with expert knowledge of planning permission and building regulations. By comparing credentials, reviewing completed projects and understanding the likely extension cost before work begins, homeowners can create their dream extension with confidence while adding valuable new space and improving long-term property value.
Frequently Asked Questions
Do I always need planning permission for a house extension?
No. Many single storey extensions are covered by permitted development rights. However, larger extensions, homes in conservation areas and projects exceeding permitted development limits usually require planning permission.
How long does a house extension take?
Most single storey extensions take around 10 to 16 weeks to complete, while larger double storey extensions generally require a longer construction period.
What does a design-and-build company do?
A design-and-build company manages the project from planning and design through to construction and completion. Having one team responsible for the whole project usually improves communication and coordination.
How can I check whether a builder is reputable?
Look for experience in house extensions, read Google reviews, review completed projects, check insurance, confirm memberships with organisations such as the FMB or NFB and ask for a detailed fixed-price quotation.
Will a house extension increase my property’s value?
A well-designed extension that creates more living space, improves natural light and enhances the functionality of your existing home can increase property value, although the exact increase depends on the location, quality of construction and local housing market.
