Double Storey Extension
Scenario Architecture is a London-based practice founded on home extensions and renovations. Our creative solutions to the space constraints of urban living transform period homes into luxurious, hard-working spaces with smart storage and fluid layouts.
Our portfolio tends toward the high end of the market, yet we know all homeowners have concerns about extension costs. Scenario works with top architects, builders and cutting-edge technology to tap the potential of every home we approach, creating luxury – and the luxury of space – at competitive prices.
At Scenario, our architects take communication seriously. Good communication and the technical knowhow to efficiently carry out our clients’ wishes are what keep costs in check. When we design a loft extension, basement, side return or rear extension, we make sure our clients have control over every decision and every material. Our client-led process is what has made Scenario so successful since our first residential project in 2007. Scenario homes are tailor made to the needs of each of our clients, and every finished project tells their story – not ours.
Our landmark residential project Scenario House, located in Stoke Newington, East London, demonstrates the potential of a fully expanded and renovated Victorian home delivered on time and on budget for a growing family. Still as fresh and efficient today as when we put it to paper, it merges contemporary steel, glass, reclaimed wood, antique brick and eco-friendly elements that look extravagant but don’t cost the earth.
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Your Double Storey Extension project
As a tool for homeowners thinking about extending into the loft, basement, garden or side return, we’ve compiled some handy research. Click here to read our illustrated overview, outlining the various stages. Remember: most residential architecture projects in and around London require planning permission from the local council. A good architecture practice will have built a successful record securing planning permission with various local councils.
To discover whether or not your architect has had success steering planning applications through your local council, visit the “planning applications” page of your local council’s website and enter the architect’s name in the search criteria.
Scenario is an established architecture practice focusing on contemporary residential design. We take on projects of every scale and scope, from home refurbishment, renovation and expansions to new-builds.
Working with Scenario Architecture
Our boutique architecture practice focuses on residential extensions, new-builds and renovations for budgets at the higher end. Our bespoke service tackles projects of every scale and scope, making city-living more accessible, comfortable and enjoyable for the future.
Our clients are kept in the know every step of the way. We consult with them regularly, from the drafting phase through moving day. In between, we work on site with all our contractors and builders with the goal that each project finishes on time and on budget.
Scenario architects adopt cutting-edge design technology as soon as it’s made available. In our experience, real-time visualisations are efficient, cost-saving tools when choosing fixtures and fittings and simulating natural light. State-of-the-art 3D design and visualisation tools are standard on all our projects.
Before breaking ground, we always produce reliable construction information with up-to-date 3D building information modelling (BIM) technology. We mine all our data from accurate 3D models to save our clients costs at every stage. The Chartered Institute of Building (CIOB) published this case study featuring a project in our portfolio. It demonstrates the benefits of advanced technology for domestic architecture.
Scenario is a RIBA Chartered Practice complying with the strict criteria of the Royal Institute of Chartered Architects. Our relationship with RIBA helps to protect our clients against health and safety issues with quality-management systems.
In our client's words
Great ideas and vision to help with our substantial improvement of a Victorian terrace. In our experience Scenario's method prioritises the final result. That may mean more professional fees or higher quotes from contractors, as they understand the exact requirements.
Great, professional service. Good drawings and models and ultimately passed planning at the first attempt with Hackney Council. Would certainly recommend!
Scenario Architecture have created an outstanding design and space that was beyond my expectations. The design was through their unique process of understanding the client’s daily scenarios and collaborating with the client to come up with a unique design. The design process is one of the most memorable parts of the process and they also stretched my existing ideas to help create this unique space. A stress free journey throughout the whole process which Scenario were indispensable by giving advice on many difficult design and build decisions.
We wanted to renovate our house in a conservation area in central London. Given this involved a complete demolition and new build with an extra floor on top, getting planning approval was always going to be tricky. Scenario did an amazing job on the new house 'envelope' and throughout the planning phase. We couldn't have wished for better from them and having succeeded in gaining planning approval owe them a very big 'thank you'.
Scenario were great at thinking imaginatively and coming up with a design for a ground floor extension that was more ambitous than other architects we spoke to. They also helped us find a contractor who was able to complete the project working within timescale and our tight budget. I would recommend for mid to large sized projects with sufficient budget to allow for full utilisation of their creativity.
So you’ve bought a home. In London and beyond, that’s a huge move. Nearly any property you purchase in Britain’s southeast will retain or accumulate value. When and if it turns out you need to grow your living space, you’ll want any enhancements you make to your home’s footprint to enhance the value of your asset, too. A good architect will factor in your home’s location, layout and structural integrity as well as the size of your family to make your desired project work for you and your budget. After all: house extension cost shouldn’t cancel out the benefits of a house extension.
It’s always difficult to project the cost of extending without evaluating the home itself, the homeowners and their plans. But it’s likely you can nearly double the size of your home’s original floor area at a fraction of the cost of the home’s value, even at upwards of £2,000 per square metre. Plus you will, of course, gain a nearly new living space without paying the stamp duty and agents’ fees associated with moving house – although you may need to purchase renovations insurance.
As with most construction, it is wise to source a few quotes for extending your house. With a range of budgets at hand, you’ll be able to assess which seem low, high and just about right, and choose accordingly. The foundation, walls and roof will suck up about 15 per cent of your costs, followed by Velux windows and rear glazing. You’ll want to price fixtures, fittings, appliances and any upgraded materials separately, so as not to be shocked when you receive your last invoice – new kitchens are particularly pricey, so keep your eyes out for deals and floor sales in the months leading up to a project.
In some neighbourhoods around London, home extensions are classified under “permitted development”, meaning they don’t require planning permission from the council in question if the final plans heed the extended volume requirements of the area. Avoiding time-consuming planning applications will save you money in the short run.
Once you’ve agreed on a budget, set up a payment plan with your architect and builders that works for everyone. A great architect should be a problem-solver first and foremost: fitting the rhythm of your life into a physical shape and making sure every element of your home can be achieved structurally legally and financially. The professional you choose should create a bespoke space deeply attuned to your needs – not just today but in the future. He or she will be able to design special touches that make your life more efficient and pleasurable.
Less a costly investment or superfluous expense, a great architect is a value-adder, paying for him or herself over and over. Many homeowners, in an effort to cut costs, end up spending much more to fix the mistakes they make themselves or entrust to a layman.
Frequently Asked Questions
- As a dynamic practice operating in London’s premium residential market, managing projects remotely and conducting virtual meetings was a very familiar territory for us, long before the pandemic began and ‘working remotely’ became the norm.
- Our clients have very busy lifestyles and may move between several different locations, both within the UK and beyond, during the lifecycle of a typical project.
- To accommodate such client needs and enable us to run their projects smoothly we had all the technology and know-how associated with remote working in place for several years.
- Read our full (Virtual) Process
- Scenario based design – We start each and every project with a meticulous analysis of our client’s vision, requirements and aspirations. We do this by asking our clients to imagine their everyday scenarios living in the completed house and describe their desired interaction with it.
- Uniquely interactive - Our client’s deep involvement in the process does not stop with completion of the brief. Our design meetings are highly interactive, informal and fun.
- Designed to reflect you – Based purely on your lifestyle, aspirations and requirements and free from externally imposed concepts, metaphors and pre-conceptions, a completely fresh and unique design will gradually emerge and it will tell your story not ours.
- Collaborative – We start the conversation with planners early and advise most of our clients to seek pre-planning advice prior to submission of a full planning application. Our experience shows that when properly consulted and liaised with, most planning case officers will be receptive to conduct a professional dialogue, increasing chances of successes.
- Strategic – We tailor a custom planning strategy for each project based on its circumstances such as planning history, local context and specific challenging elements. We sometimes split applications or introduce minor tweaks to the scheme during the consideration period in conversation with the officers to prevent one contentious element from jeopardising approval of the main scheme.
- Professional – Our experience shows that the quality and clarity of the submission in terms of background research, planning history of the property and context, precedent and of course the arguments presented to support the case has a tremendous effect on success rate.
- The decision period clock only starts ticking once the application is validated by the Council, This requires then to check that the forms are completed correctly and that the submission contains all the necessary drawings, statements and reports.
- Although required by law to provide a decision within the statutory eight weeks period, it is not uncommon for councils to miss the deadline of the consideration period, normally only by a few days, sometimes longer.
- In some cases the council may ask us as your agent for an extension of time, this may be requested due to internal reasons or as an acceptable result of a professional discussion that we are conducting with them about certain aspects of the application that they are not sure about.
- Our experience shows that planning officers respond better to projects when they feel consulted and collaborated with. We find that when we truly listen to their often helpful and valid feedback and treat them as consultants for the projects and not representative of an evil enforcing authority, they tend to collaborate well with us and demonstrate increased flexibility.
- Although the council in theory have eight weeks to consider your application, in practice they are constantly overloaded. They will only look at your application in the last few days of the consideration period. If this is the first time that they come across a scheme that they were never consulted about, our chance to secure permission for you in a single attempt is significantly compromised.
- The standard practice is for the council to consider the full planning application as submitted and then issue a yes or no decision. Case officers are not required or even encouraged to enter a discussion with us or accept resubmission of minor changes to the proposed scheme during the consideration period.
Double Storey Extensions: Guide to Planning, Design and Build
Building a double storey extension can be an exciting and rewarding experience. Making the right decisions during the planning stage will ensure that you get exactly what you want within your budget. This guide will take you through some of the most important considerations when designing and building a new two-storey extension to your home or office.
Double story extensions are effective because:
- They are cost-effective
- It improves the layouts of existing structures
- They are more sensible than moving houses
What Is a Double Storey Extension?
A double storey extension is a second-floor level added to the top of your home. It can be an excellent way to add more space without moving houses and make more efficient use out of the room you already have.
You can achieve a double storey extension with several different materials, but the most common is brick or concrete blockwork on the exterior and plasterboard lining on both sides of interior walls.
They are often combined with additions to living spaces such as kitchen extensions to make them more functional for families. This arrangement also provides plenty of space for storage and utilities.
It is worth noting that a double storey extension will increase the weight of your home, which can impact the foundations depending on where you live. If there are any questions about whether this would be suitable in your area, it is best to consult with a structural engineer before undertaking any work with an architect or builder.
Adding a Double Storey Extension to the Rear
A double storey extension to the rear is an excellent way of adding space without moving house or changing your existing home’s layout. The first thing you need to consider when designing and building this type of addition is how it will connect with other parts of the house, such as stairs – if there are any at all. For instance, to connect the extension with the upper floors of an existing home, you’ll need a staircase.
One advantage of adding the extension to the rear is that you will be adding square footage to the back of your house rather than at the front. As a result, there should be less traffic going up and downstairs in this part of the house.
If there is no upstairs access, it may make sense to run your stairs down one side or along the back for easy movement between rooms. It’s also worth considering how you want the space in your new extension – do you want more bedrooms with en-suites or a living room with enough space for the whole family?
Adding a Double Storey Extension to the Side
If you are considering adding a double storey extension to the side of your home, it is essential to consider how this will affect light. For example, the orientation and inclination of windows in an existing property can be affected by extending one side. As well as that, extra rooms created with a two-storey extension on either side may not receive natural light at the same time of day, which will make it difficult to use.
A two-storey extension on one side may not be possible, depending on your home’s orientation and weight rating. If you are unsure whether this would work for you, consult with an architect or builder beforehand.
An advantage of this setup is that it can be a good opportunity to add more living space if your home is in an urban area where houses are close together.
Why Are Two-Storey Extensions So Popular?
It is difficult to add an extension to the front of your property and would increase traffic on stairs.
The number one reason why double storey extensions are so popular with homeowners is their space-efficient design. In addition to being an excellent way for families or those living alone to make better use of rooms they already have, it can be a great way to add extra living space in urban areas where there is not much room for new homes.
Most people opt for brick or concrete blockwork on the exterior with plasterboard lining. Still, you can also get an extension built using timber frame and clad with weatherboard, asbestos cement boards products like Reynobond® Fleece-backed metal sheets or a mix of materials.
Permitted Development Rights for Two Storey House Extensions
In England, a two-storey extension is permitted development. This means that there are no planning requirements for an individual building inspector to approve this type of construction – as long as the householder follows certain rules and regulations.
A permit is required in Wales if you’re extending on more than 25% of the original floor area or if the extension is less than 0.25 metres from a boundary line – but in England, this isn’t necessary unless you are applying for planning permission because of other considerations
There Are Certain Rules and Regulations Which You Must Follow When Adding On Two Storeys
– It can’t be taller than the highest part of your house
– It can’t exceed a height and width greater than half that of your home extension. For example, if you have an existing 100m² floor space on three storeys, then it would not be possible to add a two-storey extension with more than 50m² in area
– It can’t be any closer than 0.25 metres to a boundary line
– You must tell your neighbours about the planned extension and give them written notice of when it will start
Planning Permission To Build a Two Storey Extension
You will need planning permission for any two-storey extension which is more than 25% of the original floor area or if it’s less than 0.25 metres from a boundary line.
To get planning permission in England, you must submit an application to your local authority that includes:
- A site plan (showing where the extension will be)
- A maximum floor plan (showing the size of the extension, including internal stairs and landings)
- The height, width and area of any new extensions. You must also show these details on a site plan if possible
If you are building an extension that is less than 25% of your original floor space, it is unnecessary to submit an application.
Do I Need Building Regulations Approval To Build a Double Storey Extension?
Building Regulations Approval is unnecessary for a two-storey extension if it falls under the ‘Permitted Development Rights’ section of the Building Act (England).
Two Storey House Extension Ideas: How To Design Yours?
Two-storey extensions offer a great way to make better use of rooms you already have at home or add extra living space. But, how do you design them?
Internal Layout Ideas for Downstairs and Upstairs Rooms
Downstairs: The downstairs design can be flexible, but here are some ideas for a two-storey extension concerning the layout of rooms.
- You might want to use your ground floor as an office or a craft room – which could also work well with kids’ games and messy activities like cooking do their best.
- You might want to use the first floor as bedrooms – which could be great for younger children who need their own space.
Upstairs: There are many ways you can design a two-storey extension upstairs, but here are some ideas and considerations that may come in handy.
- It’s essential to consider your family’s needs and how you want to use the new space.
- Put bedrooms on either side of a central stairway, with one designated as an en suite bathroom – this could be great if there are older children sharing rooms who need privacy from younger kids.
- Separate bedrooms by gender or age group, which would make it easier for parents to keep track of their children.
- Consider the size and layout of rooms because this may affect your living space on ground level – for example, if you place an ensuite upstairs, there will be less room downstairs in a two-storey extension design.
Bi-Folding vs Sliding Doors for Double Storey Extensions
When putting in a two-storey extension, you may want to consider the doors.
- Bi-folding doors will give you more space and make it easy for people to walk through – but they require lots of width on your staircase or new hallway
- Sliding doors are great if there’s no room on the stairs, as they don’t need a lot of width. But, they can be tricky to use if you’re not used to them
Exterior Materials for the Extension
Don’t forget to think about the materials you will use for your exterior, as these could also affect how much light comes into the extension.
- Brick and stone are solid but can be expensive – they’re suitable in two-storey extensions that have been around a while
- Tiles or cladding create a clean look with lots of natural light but can be expensive
- Timber cladding is lightweight and relatively inexpensive, making it a popular choice for two-storey extensions in the UK
Adding a Two Storey Extension to a Detached House
A two-storey extension to a detached house can have many benefits, either for the home or its occupants. First, you must get an architect involved in the planning stages – they will help with all aspects of design and construction.
Adding a Two Storey Extension to a Semi-Detached House
A two-storey extension to a semi-detached house can be a great way to increase the living space, but you must get an architect involved in design and construction – they will help with all aspects of planning.
Adding a Two Storey Extension to a Terraced House
A two-storey extension to a terraced house can be great for increasing the living space, but it’s essential you get an architect involved because they will help with all aspects of design and construction.
Adding a Double Storey Extension to a Listed Building
A two-storey extension to a listed building can provide you with much-needed living space without compromising the character of your home. It’s important that you get an architect involved in planning – they will be able to help with all aspects of design and construction.
Adding a Double Extension in a Conservation Area
A two-storey extension in a conservation area can be great for adding living space to your home, but it’s important you get an architect involved because they will help with all aspects of design and construction.
How Do You Find and Choose the Right Extension Architect?
- Ask friends, family and neighbours for recommendations – then ask them what qualities the architect they recommend has
- Talk to extension architects in your area; you may want someone who lives close by or one that is willing to travel. Find out how big their team is (building an extension can be a very time-consuming process)
How Do You Find and Choose a Good Reliable Builder for Building a Two Storey Extension?
- Make sure your builder has experience in building extensions – it’s important that they can adapt their plans and ideas if something goes wrong
- A cheaper quote may tempt you, but some builders will use inferior materials or cut corners
What Is The Cost of a Two Storey Extension?
- A two-storey extension on a standard detached house should cost around £65,000 – £95,000
- A two-storey extension on a semi-detached house should cost around £70,000 – £85,000
- A two-storey extension on a terraced house should cost around £65,000 – £95,000.
How Long Does It Take to Build a Double Storey Extension?
The time it takes to build a two-storey extension will depend on many factors, including the size of your extension and whether or not you’re building from scratch. It can take anything from six to eighteen months for an average-sized double storey extension in either a detached or semi-detached house with no planning issues.
How Can Scenario Architecture Help?
- We offer free consultations so you can find out what your options are and how much it will cost
- You must be clear about the layout of your extension before work begins – so you can get help with all aspects of design.
By following the above considerations, you will be able to get the results you need.