10 Inspiring House Extension Ideas That Transform Your Home

10 Inspiring House Extension Ideas That Will Transform Your Home


If you’re craving more space in your home but don’t want to go through the hassle of moving.  A house extension might be the perfect solution for you. Not only can it provide the extra room you need, but it can also completely transform the look and feel of your home. In this blog post, we will explore 10 inspiring house extension ideas.  That will not only enhance your living space but also add value to your property. So let’s dive in and discover the endless possibilities a house extension can offer to elevate your living experience!

Modern Glass Box Extension:

For those seeking a contemporary touch, a modern glass box extension is a show-stopping choice. The sleek lines and transparent walls create a visually stunning addition that floods your home with natural light. Whether used as a dining area, home office, or simply a place to unwind, this extension will make a striking statement.

Stylish Side Return Extension:

Maximize the potential of your narrow side alleyway with a side return extension. This popular choice opens up your kitchen and living space, creating a spacious and airy environment. The additional square footage allows for a larger kitchen island, dining area, or even a cozy seating nook. Say goodbye to cramped quarters and hello to a functional and inviting space.

Double-Height Extension:

If you’re looking to create a grand and impressive space, consider a double-height extension. This design feature adds a sense of drama and elegance to your home. With soaring ceilings and expansive windows, you’ll have a room that feels spacious and luxurious.  Perfect for a stunning living area or an awe-inspiring entrance hall.


Loft Conversion:

Unlock the hidden potential in your attic with a loft conversion.  Offering a cost-effective way to add extra bedrooms, a home office, or a playroom for the kids. Embrace the charm of exposed beams and skylights that bathe the space in natural light.  Creating a warm and inviting atmosphere. A loft conversion not only enhances your living space but also significantly increases the value of your property. Discover the possibilities of transforming your underutilized attic into a functional and stylish extension that meets your family’s needs and adds long-term value to your home.

Garden Room Retreat:

Create a tranquil retreat in your backyard with a garden room extension. Whether you envision a home gym, art studio, or a quiet reading nook, this extension offers a peaceful sanctuary away from the hustle and bustle of daily life. With large windows overlooking your garden, you can enjoy the beauty of nature while indulging in your favourite activities.

Wraparound Extension:

For those who desire a significant expansion of their living space, a wraparound extension proves to be an ideal choice. This design wraps around the side and rear of your home, resulting in a seamless flow between existing and new rooms. The wraparound extension offers a flexible layout, accommodating a larger kitchen, additional bedrooms, or a spacious open-plan living area. With its expansive design, this extension allows you to create a harmonious and cohesive living space.  That perfectly aligns with your lifestyle and preferences. Embrace the opportunity to enhance your home’s functionality and aesthetics with a wraparound extension that maximizes your property’s potential.


Basement Extension:

Optimize your underground space by choosing a basement extension, allowing you to make the most of your home’s potential. Whether you envision a home cinema, a wine cellar, or an additional living area.  A house extension adds valuable square footage without altering the exterior aesthetics of your home. With meticulous planning and thoughtful design, a basement extension can transform into the ultimate entertainment zone or a serene private retreat, providing endless possibilities for enhancing your lifestyle and enjoyment at home. Embrace the hidden potential beneath your feet and create a space that complements your needs and desires perfectly.


Sunroom Extension:

Embrace the beauty of natural light year-round by adding a sunroom extension to your home. This bright and airy space is meticulously designed to capture sunlight throughout the day, making it an inviting spot for relaxation or indoor gardening. From enjoying a book bathed in warm rays to cultivating your favorite plants, a sunroom extension brings the outdoors inside while providing a cozy sanctuary. Immerse yourself in the tranquil atmosphere and bask in the glow of nature’s gift, creating a harmonious connection between your indoor and outdoor living spaces. With a sunroom, you can savor the beauty of each season without leaving the comfort of your home.

Contemporary Orangery:

By opting for a contemporary orangery, you can combine traditional elegance with modern design. This extension is characterized by its brick or stone base and large glass panels, which offer a harmonious blend of classic and contemporary aesthetics. The result is a versatile space that can be used as a dining room, home office, or even a luxurious lounge area. Embrace the timeless charm of a traditional orangery while enjoying the benefits of modern design and functionality.

Modern Studio Extension:

Transform your home into a creative haven by adding a modern studio extension. Whether you’re an artist, musician, or writer, having a dedicated space to pursue your passion is essential. This extension can be fully customized to meet your specific needs, offering ample natural light and a peaceful atmosphere that will inspire and enhance your creative work. Enjoy the convenience of having a private sanctuary right at home, where you can immerse yourself in your artistic pursuits and let your imagination soar.


Whether you’re yearning for more space, looking to increase the value of your property, or simply seeking a stunning transformation, these 10 inspiring house extension ideas are sure to capture your imagination. Ranging from modern glass box extensions to basement conversions, there’s an extension style to suit every taste and lifestyle. Embrace the opportunity to transform your home and create a space that truly reflects your vision and needs.

Remember, when planning a house extension, it’s essential to consult with a professional architect or builder who can expertly guide you through the process and ensure your ideas come to life seamlessly. Get ready to embark on a journey of expansion and transformation with a house extension that will elevate your living experience to new heights.

If you require assistance with any aspect of your house extension project, our team of expert architects is here to help. Contact us today to explore the possibilities and turn your dream extension into a reality. With our expertise and dedication, we’ll collaborate with you to design a space that enhances your home and enriches your lifestyle. Let’s bring your vision to life together!

Designing the Perfect Extension Part 1

Designing the Perfect Extension: part 1


Are you looking to design the perfect extension to your home in Harrogate, Kent or London? Discover expert advice from local architecture firms near you on designing a seamlessly blended extension that harmonises with your existing structure. Achieve the perfect balance between old and new with these tips and tricks:

Tip 1: Understand the Existing Architecture:

Gain insights into the architectural style of your home in Harrogate, Kent or London. Consider its unique features, materials, and design elements. This understanding will guide you in creating a cohesive design that respects the character of your local architecture.

Tip 2: Complement, Don’t Contrast:

Work with local architects near you to develop a design that complements the existing structure. Incorporate elements from the original architecture into the extension, such as matching rooflines, window styles, or materials. This approach establishes visual cohesion and a seamless transition between the old and new sections of your home.

Tip 3: Seek Proportional Balance:

Ensure a proportional balance between the existing structure and the extension. Collaborate with local architects in Harrogate, Kent or London to assess scale and massing, avoiding an overpowering or disproportionate design. Their expertise will help create a visually pleasing and harmonious integration.

new 3-bedroom single storey home in Upper Hopton

Tip 4: Material Selection:

Choose materials that seamlessly integrate with the existing ones in Harrogate, Kent or London. Work with local architects familiar with local materials and architectural styles. Consider matching or complementing original materials, such as brick, stone, or timber, for a unified aesthetic that blends old and new seamlessly.

oak cladding - Architecture and Design

Tip 5: Pay Attention to Details:

We understand the significance of small details in blending old and new. Focus on architectural details like cornices, mouldings, or decorative elements, ensuring a smooth transition from the existing structure to the extension. Consistency in these finer details enhances the overall coherence of your design.

designing the perfect Architectural house extension

Tip 6: Embrace Transitional Spaces:

Explore the inclusion of transitional spaces, such as atriums, courtyards, or glazed connectors, in collaboration with local architects. These areas serve as elegant bridges between the old and new, allowing natural light to flow through both sections while visually connecting them.

Tip 7: Seek Professional Expertise:

Consult local architects near you experienced in blending old and new architecture in Harrogate, Kent or London. Their expertise ensures a thoughtful and cohesive design that respects the integrity of the original structure while seamlessly incorporating your desired extension.

Ready to begin your extension project in Harrogate, Kent or London? Contact your local architecture firm to receive guidance and expertise in creating a harmonious, locally-inspired space that combines the best of both worlds. Start your journey towards the perfect extension today with our architecture firm near you in Harrogate, Kent or London!

Small Projects, Big Impact: Architecture Firms Transform Homes through Thoughtful Design

Small Projects Big Impact: Architecture Firms Transform Homes through Thoughtful Design

Architecture firms have the power to transform homes through thoughtful design, creating spaces that not only meet the functional needs of the residents but also enhance their overall quality of life. Here are some small projects that can have a big impact when it comes to transforming homes:

Open Floor Plans:

Experience the power of open floor plans, designed by skilled architects who can remove walls to create a sense of spaciousness and improve social interaction. With expertly crafted designs, architects can maximise natural light distribution, fostering a seamless flow between rooms.

Natural Light Optimisation:

Harness the beauty of natural light to enhance your home’s ambiance and energy efficiency. Architects leverage their expertise to strategically position windows, skylights, and light wells, inviting an abundance of natural light that radiates warmth and connectivity with the outdoors.

Functional Storage Solutions:

Architects craft custom storage solutions that elevate organisation while maintaining a clean and uncluttered aesthetic. Through innovative built-in cabinets, hidden storage spaces, and creative shelving options, your home can achieve optimal storage capacity without compromising style.

open plan ensuite - carter-designs

Outdoor Living Spaces:

Expand your living area with captivating outdoor spaces designed by architects. Engage in relaxation, entertainment, and appreciation of the natural surroundings on thoughtfully designed decks, patios, or terraces that seamlessly merge with your indoor spaces.

Energy Efficiency Upgrades:

Embrace sustainable design principles and reduce your environmental impact with the guidance of architects. By incorporating energy-efficient appliances, effective insulation, and passive heating and cooling strategies, architects help homeowners lower energy bills while prioritising eco-friendly living.

Universal Design:

Architects employ universal design principles, making your home accessible and inclusive for people of all ages and abilities. With wider doorways, no-step entries, lever-style door handles, and discreetly integrated grab bars, architects prioritize comfort and convenience for everyone.

Universal Design:

Architects employ universal design principles, making your home accessible and inclusive for people of all ages and abilities. With wider doorways, no-step entries, lever-style door handles, and discreetly integrated grab bars, architects prioritize comfort and convenience for everyone.

polished concrete house - Architecture and Design

Kitchen and Bathroom Remodels:

Unleash the true potential of your home’s focal points – the kitchen and bathroom. Architects reimagine layouts, update fixtures, and introduce modern design elements to create highly functional, visually appealing spaces that elevate your home’s value and living accommodations. We recommend heading to trade shows and showrooms for more inspiration.

Landscape Design:

Collaborating with landscape architects, architects craft outdoor spaces that harmonise with your home’s architecture, boost curb appeal, and foster a strong connection with nature. Elevate your home’s exterior through beautifully designed landscapes that complement and enhance its overall design. We personally like the work of Artisan Landscapes.

Adaptive Reuse:

Architects expertly transform underutilised spaces like basements or attics into functional areas tailored to your specific needs. Unlock the hidden potential of your home without extensive renovations or additions, adding both value and purpose to your living space.

Smart Home Integration:

Seamlessly integrate cutting-edge smart home technologies into your architectural design. Architects incorporate systems for lighting, heating and cooling, security, entertainment, and automated window treatments, providing unmatched convenience, security, and energy efficiency.

Architectural services - Marble Living room

In summary, architectural expertise can bring remarkable transformations to your home, enhancing both functionality and aesthetics. Let architecture firms unlock the full potential of your living space by creating designs that align with your unique needs and aspirations. Experience a truly transformative lifestyle through the power of thoughtful architecture and design.

Ready to transform your home? Contact our experienced architects today and let us bring your vision to life. Together, we can create a space that not only meets your functional needs but also elevates your quality of life. Don’t wait any longer – take the first step towards your dream home now!

Remember, the possibilities are endless when it comes to transforming your home with the expertise of skilled architects. Contact us today to get started on your exciting journey.

Small but Mighty: Maximising Space in Small-Scale Architecture Projects

Maximising space in small-scale architecture projects.


Are you looking to maximise space in small-scale architecture projects? Space optimisation is crucial for efficient design in such projects. By employing functional zoning, open floor plans, and multifunctional furniture, you can make the most of the available space. Incorporating built-in storage and utilising wall space are key strategies to enhance storage options and minimize clutter. Additionally, maximising natural light, utilizing mirrors for reflection, and strategically placing furniture help create a sense of spaciousness. Consider incorporating vertical gardening and using light colours to further enhance the perceived size of the space. By implementing these space-saving solutions, you can optimise the functionality and visual appeal of small-scale architecture projects.

Maximising space in small-scale architecture projects can be achieved through careful planning and strategic design choices. Here are some tips to help you make the most of limited space:

Tip 1: Functional Areas

Clearly define the different functions or activities that will take place in your space, such as living, sleeping, working, and storage areas. By delineating these areas, you can plan the layout accordingly and ensure that each area is optimised for its specific purpose. This helps prevent space from being wasted or used inefficiently.

Tip 2: Open floor plans

An open floor plan removes unnecessary walls and partitions, creating a more spacious and flexible environment. It allows for better flow and movement between areas, maximising the usable space. Additionally, an open layout enables natural light to penetrate deeper into the space, making it feel larger and more open.

Tip 3: Multifunctional furniture

In small-scale projects or tight spaces, selecting furniture that serves multiple purposes is crucial. For example, a sofa that can be converted into a bed or a coffee table with built-in storage compartments provides both comfort and functionality without occupying excessive space. Look for innovative designs and compact furniture pieces that can be easily adapted to different needs.  Utilise space over tall cupboards or kitchen units, essentially these spaces become dust traps, custom built-in storage over, looks more appealing and can really free up other areas. Which leads on to tip 4


Tip 4: Built-in storage solutions

To maximise space, consider incorporating built-in storage solutions wherever possible. Custom-designed shelves, cabinets, and drawers can be seamlessly integrated into the architecture. Utilise vertical space by installing tall storage units or floor-to-ceiling shelving. Make use of under-stair spaces, wall niches, eaves storage, or other overlooked areas for additional storage options.

A good carpentry firm should be able to assist, McClark Joinery has some really beautiful work.  In a. small child’s bedrooms, try installing a loft bed, this frees up space below and creates a playful area both above and below.  Built-in storage can be critical for maximising space in small-scale architecture projects.


Tp 5: Utilise wall space

Walls offer valuable real estate for storage and organisation. Install shelves, hooks, and racks to hang or display items such as books, decorative objects, or kitchen utensils. This not only frees up floor space but also adds visual interest to the walls.


Tip 6: Natural light and mirrors

Natural light plays a crucial role in making a small space feel larger and more inviting. Incorporate large windows, skylights, or glass doors to allow ample daylight into the space. Additionally, strategically placing mirrors on walls can reflect light and create an illusion of expanded space. Mirrors also add depth and make the room feel more open.  Mirrors work well for small gardens too, however, just be conscious of size and positioning for birds.  If you have the space, clever use of a water feature can add reflections whilst being more wildlife friendly than a mirror.

Tip 7: Optimal furniture placement

Carefully consider the placement of furniture to maximise space utilisation. Avoid blocking pathways or creating obstacles that hinder movement. Create a balance between comfort and functionality by selecting appropriately sized furniture pieces. Consider using compact or modular furniture that can be easily rearranged or folded away when not in use, providing flexibility and freeing up space.  Either draw up a floor plan or tape out furniture on the floor to avoid back-breaking repetition!.

Tip 8: Vertical gardening:

If you have limited outdoor space, vertical gardens or hanging planters can be a great way to incorporate greenery without taking up valuable floor space. Attach planters to walls or hang them from ceilings to add a touch of nature and aesthetic appeal to your small-scale project.  Remove any large shrubs or planting that can make a small garden feel more compressed.

Prior to removing trees check with your local authority for any T.P.O.’s (Tree Preservation Orders) in your area.  Push planting out to the perimeter and the use of raised planters will provide more useable space and interesting focal points that can also integrate bench seating and even an outdoor kitchen.

Tip 9: Use light colours

Light-coloured surfaces, including walls, ceilings, and furniture, help create an illusion of more space. Opt for neutral or pastel shades as they reflect more light, making the area feel airy and open. Light colours also contribute to a visually cohesive and harmonious atmosphere.

Tip 10: Minimise clutter:

Probably my biggest pet peeve is clutter.  Clutter can quickly make a small space feel cramped and chaotic. Regularly declutter your space and adopt smart storage solutions to keep things organised. Consider utilising hidden storage compartments, such as ottomans with storage space inside or beds with built-in drawers, to hide away items and maintain a clean and uncluttered environment.  Under stairs and eaves storage can help to store items that typically you don’t need on a regular basis.


By implementing these tips, you can maximising space in small-scale architecture projects. and create functional, visually appealing, and efficient living or working environments.  If you have project you need help with get in touch, we can provide full joinery designs and detailed drawings and even recommend carpenters for you.

Planning a House Extension in several steps

Planning a House Extension in several steps


Planning a house extension involves several important steps to ensure a successful outcome. Follow this comprehensive step-by-step guide to effectively plan and execute your house extension project.

Step 1: Determine Your Goals

Start by clearly defining the purpose of your extension. Identify specific goals such as creating more living space, adding bedrooms, expanding the kitchen, or building a home office. Understanding your objectives will guide the entire design process.

Step 2: Assess Feasibility

To ensure the feasibility of your extension project, it’s essential to consider several factors. Start by evaluating local regulations, as they may dictate specific limitations or requirements for your planned extension. Additionally, take into account any site constraints, such as available space, existing structures, and environmental considerations.

Budgetary factors are equally crucial in determining the feasibility of your project. Analyze your financial resources and align them with the scope of your desired extension. It’s essential to be realistic about what you can afford and plan accordingly.

As you assess the practicality and potential challenges of your project, seeking professional advice from architects or designers is highly recommended. Their expertise can help you navigate the complexities of your project, identify potential obstacles, and provide innovative solutions to achieve your vision within the given constraints. By taking these steps, you can approach your house extension with a well-informed perspective, increasing the likelihood of a successful and satisfying outcome.

Step 3: Set a Realistic Budget

To ensure a successful house extension project, it’s crucial to establish a realistic budget that encompasses all associated costs. This should include design fees, construction expenses, materials, permits, and any additional services required. By clearly defining your financial limitations from the outset, you can ensure that your project aligns with your budgetary constraints.

We are here to assist you in determining what budget is realistic for your house extension. Our expertise and experience in architectural projects can help you make informed decisions and prioritize your spending to achieve the best possible outcome within your financial means. Together, we can work towards creating a well-planned and cost-effective extension that meets both your vision and budgetary requirements.

carter designs & architechture harrogate

Step 4: Hire Experienced Professionals

Engage with reputable architects, designers, or builders experienced in house extensions that can recommend a designer. They will assist you in developing a design that meets your needs, complies with regulations, and maximizes the potential of your space. Professionals can also help with obtaining necessary permits and approvals.  You can use the RIBA or CIAT’s website to find a professional chartered practice.

open plan ensuite - carter-designs

Step 5: Design Development

Collaborate closely with your chosen professional to develop a detailed design for your extension. This includes creating architectural plans, 3D renderings, and considering material selections. Incorporate your preferences while considering functionality and aesthetic appeal.


Step 6: Obtain Necessary Approvals

Indeed, depending on your location, obtaining planning permission or building permits may be necessary for your house extension project. To navigate this process effectively, your architect or designer can provide valuable guidance in preparing and submitting the required documents to the relevant authorities. However, it’s important to remember to factor in the time required for the approval process, as it can vary based on local regulations and the complexity of your project.

By proactively addressing these requirements and diligently working with your architectural professional, you can ensure a smoother and more efficient planning process. This proactive approach will significantly contribute to the timely realization of your house extension project, allowing you to enjoy your extended living space without unnecessary delays or complications.

Step 7: Select a Reputable Contractor

To ensure the success of your house extension project, it is essential to solicit quotes from reputable contractors and select the one that best fits your project requirements and budget. They should provide a detailed and itemized list of what is included in their quotation. Additionally, make sure they possess the necessary licenses, insurance, and sufficient experience in undertaking house extensions.

Furthermore, thoroughly review their previous work and request references from past clients to ensure their reliability and craftsmanship. By conducting a comprehensive evaluation of potential contractors, you can confidently choose the right team to bring your house extension vision to life. This careful selection process will help you avoid potential issues and guarantee a smooth and successful construction journey.

Always use a contract, for smaller works this may not be feasible but for anything over the value of £30,000 we recommend a JCT Homeowner Contract.  We will write another post on contracts soon.

house bungalow extension canterbury

Step 8: Develop a Construction Schedule

Work with your contractor to establish a detailed construction timeline, including milestones, deadlines, and an estimated completion date.  Allow flexibility for unexpected delays or changes during the construction phase.

Step 9: Prepare for Construction

Make any necessary arrangements before construction begins, such as notifying neighbours and managing utilities. Clear the construction area and protect existing structures or landscaping.

Step 10: Construction Phase

Maintain regular communication with your contractor to monitor progress. Visit the site frequently to ensure work is on track and address any concerns promptly. Maintain open lines of communication with the contractor to address issues or changes that may arise during construction.

Step 11: Finalize the Project

After construction is complete, conduct a thorough inspection of the extension with your architect and contractor to ensure adherence to plans and your expectations.  Address any outstanding items or deficiencies before officially accepting the project as complete and releasing final payment.


Remember that the process of planning a house extension can vary based on specific requirements and local regulations. Additionally, there is a lot more to planning and completing a successful building project. To achieve the desired results, it is essential to work closely with professionals, adhere diligently to applicable rules and regulations, and maintain open communication throughout the process. By doing so, you can ensure a seamless and successful outcome that meets your expectations and complies with all necessary standards.

To re-cap the key to a successful project is:-

  1. Hire a professional to obtain planning permission, draw up detailed information for builders to price from
  2. Set a realistic time scale
  3. Listen to the advice you are paying for
  4. Always obtain detailed written quotations
  5. Never be rushed or bullied into starting works if you are not comfortable
  6. Check references and if the projects were completed on time and on budget
  7. Always use a contract
  8. A hired professional to oversee the work can ensure you are not overpaying for work, carry out regular inspections, hold back money with a JCT contract to cover any defects, provide a certificate at the end of the project and be on hand to guide you through the project.

How much does a house extension cost?

How much does a house extension cost?

When considering a house extension, the cost can vary depending on factors such as the type of extension.   material finishes, project location, access to the site, market conditions, decision-making process, and the amount of information provided. While there is no exact science to determine the cost, it’s crucial to plan and manage the project effectively to stay within your budget and achieve your desired outcome.
During the initial meeting with your architect or designer, they may ask about your budget. This information is kept confidential and helps establish if your budget aligns with the design brief. It’s important to assess not only the affordability of the extension but also its potential impact on the overall property value. If the build costs, when combined with the purchase price, exceed the market value of similar properties in the area, it could result in negative equity.

house extension cost - carter designs - architect Harrogate

Several factors influence the cost of a house extension:

Architectural services - Alwoodley house extension

Type of Extension:

Standard extensions with pitched or flat roofs and common materials like brick, render, or timber cladding tend to follow the normal cost trend. Irregularly shaped extensions or those using unique materials may require additional expenses due to the need for specialist subcontractors or extra time for completion.

Material Finishes:

The choice of material finishes can significantly impact costs. Opting for high-end finishes can quickly consume your budget, but alternatives that deliver a similar high-end appearance at a lower cost are available. Keeping an eye out for sales and deals on materials can also help reduce expenses.

Project Location:

While project location ideally should not affect costs, it has been observed that more expensive areas tend to have higher build costs. Affluent neighborhoods often attract higher-priced projects, leading to a potential increase of 30-50% in costs compared to less privileged areas. Analyzing tender returns and having a good understanding of build costs can help identify any overcharging.

Access to the Project:

The builder needs sufficient access to safely transport materials and equipment to the site. If access is limited, such as in mid-terrace properties without separate rear access, additional time and labor costs may be incurred. Foundations may need to be dug manually, and certain materials could require careful handling or alternative entry points. Clearly defining and agreeing on these costs upfront, along with well-prepared drawings and a contract, help ensure smooth progress.

Architectural services in harrogate & london
carter designs & architechture harrogate

Market Conditions:

In a busy market, builders can be selective about the projects they undertake. Waiting periods of up to 18 months for a recommended builder can occur, emphasizing the need for early project planning. Builders may provide higher estimates to secure projects, even if they are not genuinely interested in taking them on.

Decision Making:

Taking the time to make decisions during the planning phase rather than on-site can prevent delays and additional costs. Changing room proportions or reconsidering electrical positions after construction has started may result in extra labor and material charges. Clear visualization aids provided by architects, such as detailed plans, mood images, and 3D renderings, can assist in decision making.

Information Provided:

Providing comprehensive detailed information to the builder is crucial. Hiring an architectural professional who can develop the entire design package, rather than just providing designs, ensures that the concept can be accurately executed on-site. Basic planning drawings may leave gaps that require additional decisions on-site, potentially leading to delays and budget overruns. Agreeing on costs beforehand encourages competitive quotes and avoids unexpected expenses during the project.

new build house - Architecture and Design

So how much does a house extension cost?

It’s important to note that there is no fixed formula for the cost of a house extension due to these various factors. As a general guideline, most clients are advised to work with build costs of around ¬£1950/m2 (excluding VAT) for a basic finish. However, it’s unrealistic to expect a ¬£30,000 budget to cover a 50m2 house extension. It’s essential to consider that this estimate does not include professional fees, planning application costs, or any additional expenses specific to your project.

Our Free Extension Cost Calculator estimates extension costs to help you plan. Here’s how it works:

Step 1: Size and Finish

Enter your extension’s size (m²) and pick a finish level: Standard, Medium, or High.

Step 2: Calculate

Click “Calculate” for an estimated breakdown:

  • Build Costs: Core construction expense, excluding VAT.
  • Professional Fees: 7% – 12% of Build Costs.
  • Permissions and Regulations: Factor in permits and rules.
  • Contingency: 15% of Build Costs.
  • Total Costs: Range of all factors combined.


Important: VAT Not Included

Remember, VAT isn’t included. Factor it into your budget separately.


Accurate Estimates

This calculator is purely a guide and is based on prices we have seen across the country over the last 12 months.  The best way to obtain precise prices is to consult an architect or architectural technician who can provide detailed drawings that allow a builder to price from.  Your project is unique, and professionals tailor costs to your needs.


Ready to explore costs for your dream extension? Fill in the details and get started!

Extension Cost Calculator

Extension Cost Calculator

6 Tips for a more accurate estimate for your house extension,:

1. Define your requirements:

Determine the purpose of your extension and outline your specific needs. This could include adding extra bedrooms, expanding the kitchen, creating a home office, or enhancing living space. Clearly defining your goals will help you communicate your needs to professionals involved in the project.

2. Consult with professionals:

Engage with an architect, designer, or a reputable building contractor experienced in house extensions. They can guide you through the process, offer expert advice, and provide an estimate based on your requirements. Ensure they understand your budget constraints to avoid any unrealistic expectations.

3. Obtain detailed quotes:

Request detailed quotes from multiple builders or contractors. These quotes should include the cost of materials, labor, and any additional services or features specific to your project. It’s crucial to compare quotes to ensure you’re getting a fair price and to identify any variations in the services being offered.

4. Consider additional costs:

Keep in mind that there may be additional costs beyond the build itself. These can include planning application fees, building regulations approval fees, party wall agreements, professional fees (architect, structural engineer), and potential costs for services like plumbing or electrical work. Factoring in these expenses from the beginning will help you avoid surprises later on.

5. Allow for contingencies:

It’s wise to allocate a contingency budget of around 10-15% of the overall project cost. This will account for unforeseen issues or changes that may arise during construction. Having a contingency fund will give you peace of mind and ensure you’re prepared for unexpected expenses.

6. Balance cost and quality:

While it’s important to work within your budget, be mindful of the quality of materials and workmanship. Opting for the cheapest options may result in lower-quality construction, which could lead to issues in the long run. Find a balance between cost and quality to ensure your extension is durable, functional, and adds value to your home.

Remember, house extension costs can vary significantly depending on your location, the complexity of the design, and your choice of materials. The best way to get an accurate estimate is to consult with professionals who can assess your specific requirements and provide tailored costings for your project.  Contact us for a free no obligation quotation today!