Double Storey Extension: Add More Space
Add significant space with a double storey extension. Explore design possibilities, costs, and planning permissions for expanding over two floors.
With space at a premium, the appeal of extending your home has never been greater. Double storey extensions are the solution for homeowners who want to add living space without moving.
A double storey extension adds two levels of living space to a property, usually the ground and upper floors. This type of extension is perfect for adding extra bedrooms, bathrooms or bigger living areas, and can improve the overall functionality and flow of your home.
Understanding the process and benefits will help you make better decisions about your property.
Two storey extensions are a game changer for adding living space to your home, perfect for growing families or extra rooms. A two storey extension to the side or rear of your property means you can add a lot of space without taking up your garden. These are especially good for terraced houses where space is limited and every inch counts.
Double storey extensions are different from single storey extensions in design, functionality and value to your property. They can enhance the look of your home and add vital space to your family life. As you weigh up your options, knowing the benefits, popular styles and costs is key.
This is The Ultimate Guide to Double Storey Extensions for 2024. From regulations to design, you’ll get all the information you need for your extension journey.
A double storey extension is a big home improvement project that adds living space vertically, an alternative to moving by adding a ground floor and upper floor to the original house. This type of extension is versatile and can serve multiple purposes – whether you’re adding extra bedrooms or a dedicated home office.
Before you start a double storey extension you need to consider planning permission. Depending on your local development rights the project may be Permitted Development; if not detailed drawings and applications will be required. A structural engineer will also be involved as they will ensure the safe connection to the existing structure and adjust the roof pitch and ridge height as needed.
Cost wise a double storey extension is value for money but will cost more than a single storey extension, around 50-75% more. Prices start at £40,000 and can go up substantially. Key factors that affect the cost are square footage, complexity and finishes.
A double storey extension adds space and allows for design creativity, brings in natural light and makes use of garden space. So when managed properly it can be a great investment for the homeowner.
When considering extending your home homeowners weigh up the differences between double storey and single storey extensions. A double storey extension gives you more living space, increases the area on both the ground and first floors, whereas a single storey extension adds space on one level.
From a cost perspective the excavation and roofing for a double storey is the same as a single storey extension so the investment is more cost effective per square metre for the extra space you get in the double. This is because the structural elements like roofing and foundations are the same for both types of extensions.
And double storey extensions can add extra bedrooms or bathrooms without sacrificing garden space, a big consideration for small garden properties. They make use of vertical space, not increasing the footprint of the original house as much as a single storey would.
In summary if you want to add space and value to your property with minimal impact on garden space a double storey extension is the better choice.
A double storey extension can transform the amount of living space in your home. These extensions add space on both the ground and first floors, potentially new open plan living areas, home offices and extra bedrooms or bathrooms. The extra space is flexible so you can reconfigure existing rooms and create special areas that suit the family’s needs or personal preferences.
For families that need more space a double storey extension is the better option as it gives you twice the extra space of a single storey extension without having to move to a new property. The change in the home’s functionality is significant with the added bonus of flexibility so you can adjust your living arrangements as your family dynamics change over time.
Adding a double storey extension to your home can also improve energy efficiency. More windows and doors means more natural light penetration and less reliance on electric lighting during the day. A well designed double storey extension that matches the existing house can help maintain the same level of insulation throughout the property so overall energy efficiency improves.
Heating and cooling the extra space allows for better energy zoning which means more efficient climate control. Having one roof for the extended space means materials are used more efficiently and thermal performance can be optimised over multiple single storey extensions. Good design can also promote better airflow which helps with temperature regulation and reduces energy consumption – another tick for sustainability.
Investing in a double storey extension can give you a significant increase in property value of around 12-20%. This is more than a single storey extension as you are adding more floor space. Although the cost of a double storey is about 50% more than a single storey, the cost per square metre is much more economical for the extra living space you get.
A double storey extension allows you to add living space without changing the original facade, keep the character of the property and modernise the functionality. The spatial dynamics within the home and energy efficiency can be a selling point, making the property more valuable and marketable. So homeowners see double storey extensions as an investment that gives you more space and a big return on investment.
Adding a double storey extension to your home gives you more living space and options in terms of style and functionality. Whether you want a rear, side or wraparound extension each type of double storey extension has its own benefits and can be tailored to your specific needs.
Gabled extensions are a popular option, they enhance the visual appeal of the property by extending the roofline on the first floor. Adding height, gabled designs give you more space and more light inside perfect for extra bedrooms or a home office. These extensions match the original house when you use the same materials and architecture style. For aesthetic and regulatory purposes it’s important that the roof pitch of the gabled extension matches the existing house.
Double storey rear extensions are the most popular option, they give you significant space increase especially for terraced and semi-detached homes with rear garden. While adding value to the property, these extensions give you extra bedrooms or living spaces. The cost of this type of extension varies but is usually between £1200-£2200 per square metre, depending on the design and build quality. Remember rear extensions have length restrictions under permitted development rights and while planning permission may not always be required, compliance is non negotiable.
For homes with side space, a double storey side extension can be an option to expand the home. Planning permission is required here as permitted development rights do not cover side extensions at two storey level. These extensions are scrutinised for their impact on the appearance and balance of the adjacent properties. So design considerations such as a setback from the front elevation and a lower ridge height than the original house are important to make the extension subordinate not dominant. Side extensions can increase the space and functionality of the home by adding width that can serve multiple purposes – as long as there is still enough garden and parking space left.
A double storey extension is a big investment in your home, you get the extra space without the cost and hassle of moving. As of 2024 the average cost of a double storey extension in the UK is between £1200-£2200 per square metre but this can vary greatly depending on several factors. For example in the high demand area of London the cost of building a double storey extension can be between £3000-£3500 per square metre due to higher labour rates and material costs.
When you plan a two storey extension storey extension costs can vary greatly depending on design, size and materials. Flat roofs are popular for their modern look and cost effectiveness while pitched roofs can give better integration with the original house design. Thinking of two storey extension ideas that match your house architecture can increase functionality and visual appeal.
For a small double storey extension of around 30 square metres homeowners could be looking at an estimated cost of £40,000-£60,000 for a new build. This is a rough guide but costs will vary depending on the size and specifications of the project.
Professional and planning fees to be added to the overall cost which can be 10% of the construction cost for architects, 4% for structural engineers and a mandatory planning application fee of £206 in England. The cost per square metre for double storey extensions isn’t much higher than single storey extensions so it’s a cost effective option if you need more space.
Several factors can affect the total cost of a double storey extension. The size of the project is one; bigger extensions will cost more in materials and labour. Design and build quality is also critical – high end finishes and bespoke features will increase the cost.
A basic double storey extension of around 30 square metres can cost from £40,000-£60,000, prices will increase for refurbishments. If you want higher quality a medium sized build of around 50 square metres can cost between £60,000-£90,000. Costs will vary depending on internal features and local building costs throughout the UK.
Additional costs to consider are the professional fees such as architects which are generally 3-7% of the construction cost. Planning application fee is £206 and if you’re involved in a party wall agreement you’ll need to add to your budget the cost of the agreement which can be between £700-£1,000 per affected neighbour.
When planning your double storey extension you need to budget for the unknown. Disputes with neighbours over the party wall agreement may require the services of a surveyor which can cost between £1,000-£1,800 per neighbour. This should be added as a contingency to the budget.
Building control fees are also an overhead, around £950. You will need to get a building control certificate to confirm your extension meets current building regulations – you can’t skip this step.
You may need additional consultancy services depending on your property and location. These can include (but are not limited to) surveys on the existing structure, tree reports, flood risk assessments, ecology reports and reports on historic buildings which can impact on the final cost.
Given the cost range for a double storey extension from £2,000-£3,500 per square metre it’s important to budget for a contingency in your budget for these unknowns. Finally the mandatory planning fee of £206 for a residential double storey extension in England should be added to your initial budget to avoid any shortfalls.
First things first you need to navigate the regulations and permits for a double storey extension. You need to understand the difference between planning permission and building regulations as both are often required but for different reasons. Planning permission is about the look, impact on the neighbours and major structural changes to your property. Building regulations is about the detail of the build, safety, energy efficiency and functionality.
Planning restrictions and local planning rules need to be considered before starting a two storey extension. Some extensions can be done without planning permission but more significant projects will require approval. You need to check with your local planning authority to find out what’s required and avoid any issues. By following these guidelines and designing an extension that matches the original building you can create a double extension that will increase your home’s functionality and value.
Even if a double storey extension falls under Permitted Development rights, specific conditions need to be met to bypass planning permission. These rights set out parameters for things like height and footprint of the extension. If you don’t meet these conditions you’ll need to apply for full planning permission. A Full Plans application for Building Regulations approval may also be required which involves the local authority assessing your plans in depth. Compliance is usually validated within 5 weeks of submission so you need to lay the groundwork for the project ahead.
Planning permission is key when considering a two storey extension especially in a restricted city like London. Council guidelines vary so it’s best to get to know your local council’s requirements. As a rule of thumb extensions that increase the original house’s footprint or are not in-keeping with the area will require planning permission.
Following the Party Wall Act is another important consideration. This means if the extension affects a shared wall or boundary homeowners need to notify their neighbours and often need to agree a party wall agreement. Special attention needs to be given to homes in conservation areas or listed buildings as planning permission is required regardless of the size or scope of the extension. Once the work is done getting a certificate of lawful development can be useful as it confirms the project is within permitted development.
Building regulations are crucial for the structural and operational integrity of any double storey extension. These regulations are in place to make sure any new build is safe, structurally sound and energy efficient. Compliance is monitored by the local authority and covers various areas from fire safety and ventilation to waste disposal and drainage.
A Building Inspector may visit the site at multiple stages to ensure the work is in compliance with the regulations. A party wall agreement is also required by building regulations when shared walls are involved and can be as complicated as getting the planning permission itself.
For homes in conservation areas or listed buildings building regulation compliance is even more complicated. Special permissions are required and any breach can lead to serious legal issues. In these cases builders and architects need to be aware of the extra restrictions and requirements to make sure the extension is compliant and doesn’t incur penalties.
Keeping open communication with the local authority and using experienced professionals is the best way to ensure regulatory compliance for a double storey extension.
When designing a double storey extension homeowners can tailor the design to their needs and wants. A two storey extension is versatile so designs can range from modern open plan living to more segmented traditional layouts. By adding more windows and patio doors an extension can make the most of natural light and create a bright and welcoming space for relaxation and socialising.
A big benefit of a double storey extension is the amount of living space it adds. This extra volume can be used for extra bedrooms, en-suite bathrooms, home offices or additional living areas to host family and friends. Compared to a single storey extension a double storey extension gives a higher return on investment. It uses the existing roof and foundation so you get more space without the proportional cost of extending these elements.
Before finalising the plans homeowners should consider the functional use of the extra space. This forward thinking will ensure the new extension feels part of the existing home and meets the homeowner’s long term goals.
Blending the new double storey extension with the existing property is key to a cohesive look and feel. This can be achieved by matching the floor and ceiling heights and selecting interior design elements that match the original house. An extension with a completely different aesthetic like a modern kitchen against a historic home could create a jarring atmosphere.
To maintain continuity in the home thought should be given to the transition areas between the new extension and the existing property. Selecting fixtures, fittings and materials that match the original decor is essential. And when adding new rooms on the upper floor the upstairs hallway may need to be reconfigured to create a smooth and natural flow without disrupting or diminishing existing spaces.
When it comes to the aesthetics of a double storey extension design features that add visual appeal and functionality are key. A gabled extension not only gives an architectural nod to traditional design but also provides space for an office or extra bedroom and makes the extended area more usable.
Natural light can transform a double storey extension and features like glazed windows and patio doors are especially valuable. They give an unobstructed view and a bright and welcoming space which is even more beneficial when the extension looks out onto a garden or other scenic areas.
For detached homes with a central entrance a fully glazed extension can be a real showstopper that looks out onto the garden and floods the interior with light. And bi-fold or sliding doors can be game changing and merge the inside with the outside and open up the living space.
Green roofs are practical from a planning point of view and can help with meeting local requirements. And beyond that they help a new double storey extension blend with the natural environment making it an eco friendly choice with aesthetic benefits. This sustainable option adds to the aesthetic and benefits the local environment.
One of the considerations when designing a two storey rear extension is the loss of light to the existing rooms. Careful planning and structural calculations can mitigate these effects and ensure the new extension blends in with the original building and doesn’t overshadow the existing living spaces. And the external walls and rear wall of your home should be assessed to accommodate the new structure.
Double storey extensions can be a great home improvement for those who want to increase their living space and potentially add value to their property. Depending on the style and quality of materials matching the original house a well designed and built double storey extension can add 12% to 20% to the property value. A two storey extension improves the layout of the home and introduces a sense of space which is very attractive to future buyers. While the cost of a double storey extension is about 50% more than a single storey extension it adds significantly more space across both floors so better value per square foot.
Compared to moving house extending up with an extra storey can be a more budget friendly option for those who need more bedrooms or living space. Double storey extensions add space and are often more cost effective than alternatives like loft conversions. This extra space will give you a big return on investment when you come to sell the property as double storey extensions add more value than single storey extensions.
The value of a property can increase significantly with a double storey extension. This type of extension increases the appeal of a property by adding more living space which in turn will attract buyers looking for more space without having to move. Homeowners get a double benefit of financial return and lifestyle improvement.
However the final sale price is influenced by the desirability of the area and the values of the surrounding properties. So even if the extension adds value to the property to a certain threshold (say £300,000) it doesn’t mean the property will sell at that price if it’s way above the average values of the area. But a double storey extension is bespoke so you can tailor it to your family’s needs and add value not just functionality but also perceived value to the property.
When designing a double storey extension you need to consider not just the design and structural engineer requirements but also the neighbourhood dynamics. Being open about your plans and talking to your neighbours early on is polite and can create a good relationship. It may even inspire others in the area to upgrade their own properties if they see the benefits and how the development rights have been used without conflict.
Keeping your neighbours informed is a legislative requirement when the extension requires a party wall agreement under the Party Wall Act. And considering your extension’s orientation is not just important for your natural light but also for your neighbour’s. Thoughtful planning can prevent unwanted shadows falling on their garden or windows.
Having these conversations will make the project management smoother and neighbours who are informed and see the benefits of the extension are less likely to object. Keeping the lines of communication open means concerns about the changes to the roof pitch or ridge height which may affect their view or privacy are addressed and mitigated.
A double storey extension therefore needs careful planning not just in design and build but also in community relations to make sure the project benefits the area as a whole.
Choosing the right builder is key to a successful home extension. At Danesfort we deliver quality on time and on budget. We have extensive experience working on home extensions in the London area.
Danesfort ensures all projects comply with planning permissions and building regulations. We offer clear contracts that outline scope, timelines and payment terms so you’re fully informed from start to finish.
What we offer
Get in touch today to book your free consultation.
.svg)