Single Storey Extension
Finding your dream home is a huge achievement. But a dream home rarely remains that forever. Over time, our lifestyles change and our homes must adapt. A 21st-century home must be all things to its owners: a place to work, to entertain, to raise a growing family and to grow older. If you don’t want to move, your home must improve.
A single-storey extension is a way around these changes in your life. Adding more space to the side or rear of your home – or both – is a necessary luxury that will work hard to play different roles as your needs evolve. A skilled architect with knowledge of your way of life, your future plans and your neighbourhood will help develop your space to accommodate your present and your future.
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Your Single Storey Extension project
We launched Scenario in 2007 with a vision to adapt heritage architecture to 21st-century living. A highly functional home is the product of a deep understanding of the ways in which homeowners engage with their space. We work in close collaboration with our clients to make sure their needs sit at the forefront of every tailor-made design.
Our landmark project Scenario House demonstrates our commitment to the modern needs of homeowners today. The home was shortlisted for a RIBA London Award in 2018.
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
At Scenario, we tackle domestic projects of every scale and complexity, from single-storey extensions to full renovations and new-build homes. Our dynamic London studio offers a bespoke architecture service.
Our highly skilled architects collaborate closely with every client from the initial drawings, detail design and planning through tender and construction to completion – on time and on budget. If you are planning a single-storey extension, check out our portfolio of residential projects across London.
Real-time 3D design technology is the most efficient tool for seeing through a project, choosing fixtures and fittings and simulating natural light. We use innovative technology and virtual reality on all our projects. This Chartered Institute of Building case study, featuring a Scenario project, demonstrates the benefits of this advanced technology for domestic architecture.
Scenario is a RIBA Chartered Practice. We comply with the strict health and safety criteria of the country’s professional body.
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.
“Don’t move, improve,” goes the saying. And it works for most. If you love your location and find moving house a daunting proposition, there are measures you can take to expand and transform your existing home, and a single-storey extension is one of the least intrusive and least expensive options. These common home-extensions require fewer official hoops to jump through, less substantial foundations and minimal steelwork. And if they’re built well, they may also be able to accommodate a second-storey in the future.
At Scenario we design home extensions of every size and scope, within the planning constraints of the neighbourhood. We always recommend adding the most space to the home as permitted, without dramatically reducing the outdoor space. Generally speaking, the larger the extension, the more cost-effective it should be.
In a terraced house, a single-storey side-return extension is a popular way to gain valuable square footage and open up a warren-like layout. The addition of just a few square metres can allow for an open-plan kitchen-diner with a family room and separate bathroom and utility room that flows into the original lounge and hallway. A semi-detached house would benefit from a wraparound addition that occupies the side-return and reaches around into the rear garden. This would completely transform an old property into a functional home for generations.
Aside from space, one great advantage of a single-storey extension is the gaining of natural light. Single-storey additions can be glazed in any number of ways, from rooflights to Velux windows to bi-fold and concertina doors. Moreover, the redesigned layout will enable you to enlarge doorways and existing windows and push up your roof to allow in even more daylight. Enlarging windows and doorways also increases the sightlines throughout a home, making it feel bigger and safer.
If you have a garden, extending to the rear or side of your home creates an opportunity to connect indoors and out with walls of glazing and new flooring that can be carried through outside.
We also like to make sure a home-extension will allow the house to grow with the homeowners. As families progress and age, we expect generations to come and go, rooms to change function, bathrooms to work harder and people to require more assistance as they get older. This is where wider doorways, smooth transitions and large, highly functional kitchens and bathrooms to come in handy. After all, if you don’t want to move house now, you really won’t want to move house later.
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.
Single Storey Extensions: A Simple Way to Add Valuable Extra Space
It’s easy to understand why a single-story addition is a popular home renovation. It will provide crucial additional space that, when coupled with an interior redesign, can significantly enhance the layout of your house and the flow of natural light, and it can also (in many instances) be completed within the Permitted Development limits. It’s also a lot less expensive than moving house to gain more space, and will add value to your current home too. Read on for some useful information about why single storey extensions are a good idea and how to get started with yours.
How Much Does A Single Storey Extension Cost?
Before you begin planning the design of a single-story extension, you must first establish a budget and verify that you can afford what you’re planning. Begin with construction expenses, which can be broken down as follows:
- If you’re on a tight budget, you can construct a single-story addition for about £1,500 to £1,900 per m2 for low quality (e.g., 4m × 5m expansion would cost around £30,000).
- Expect to spend between £1,900 and £2,200 per m2 for good quality (e.g., £38,000 for a 4m x 5m extension).
- A high-spec extension will cost between £2,200 and £2,400 per m2 (eg up to £44,000 for a 4m x 5m extension).
As well as these costs, you’ll need to think about:
- Architect’s fees (these will be somewhere between 3 and 7 percent of the cost of construction, plus drawings)
- Structural engineer (between £500 to £1,000)
- Surveyor (between £500 and £1,500)
- Project management (between 3 and 7 percent, of a fixed fee)
- VAT (20 percent)
- Planning fees (£206 in England)
- Building control charges (usually between £200 and £900)
- Party wall agreement (up to £1,000 per neighbour affected)
Depending on your project, you may not need all of these additional experts to help you. For example, you can manage your own project, and you will only need a structural engineer if roof joists of foundations have to be moved, removed, or added.
Is Planning Permission Required For A Single Storey Extension?
A single storey extension that: covers more than half of the land surrounding your home; extends towards a road; increases the overall height of the building; extends more than 6m from the rear of an attached house; extends more than 8m from the rear of a detached house; is taller than 4m; or uses more than half of the land surrounding your home (or a combination of these things) will require planning permission.
A competent architect or builder will be aware of these restrictions, but it’s best to double-check to prevent multiple planning applications and to ensure that planning isn’t neglected entirely. Remember, if the extension’s height and footprint satisfy permitted development requirements, you may be able to construct it without obtaining planning permission.
Never assume anything, though, particularly if you reside in a Conservation Area. You should apply for a certificate of lawful development from your local authorities even if you don’t need planning permission, just to be sure.
Single Storey Extensions And Building Regulations
Any kind of extension must adhere to building regulations, even if you don’t technically need planning permission for it. You must apply for the work via your local authority’s building control department. Each authority has its own set of fees, or you may prefer to use a private licenced building control company. Some contractors are building control certified, which means they can do work without contacting the building control department.
What you choose is always going to be down to you, your circumstances, and your personal choices, but the end result must be an extension that meets all necessary building regulations.
Do I Need A Party Wall Agreement?
Depending on the relationship you have with your neighbours, you may be able to convince them to sign a party wall agreement waiver form. No matter what the situation, you’ll need to show them your plans and take them through all your ideas for your single storey extension so that they fully understand what you are thinking of doing.
If they’re not close friends, or you think it would be better to go through more formal channels, you will need to employ a surveyor to establish party wall agreements. Remember, your neighbours have the right to find their own surveyor if they do not wish to share yours, and you’ll need to bear the cost of this.
How Big Can The Single Storey Extension Be?
The size of your single storey extension will be limited by planning permission restrictions, such as how much your home has previously been expanded, but keep in mind that the bigger the extension, the more cost-effective it will be. However, an extension that significantly decreases the size of the garden may have a detrimental effect on the attractiveness of your house to potential purchasers. The key thing to think about is whether or not you should go big just because you can.
Designing A Single Storey Extension
Here are some things to think about whether you’ve hired an architect or are designing your extension yourself with the help of an experienced builder. The kind of extension design you select will depend on the style of home you are working with, even though it’s sometimes mandated by planning permission or permitted development regulations too.
When planning an extension, it is easy to forget about how the remainder of the home will sit alongside the new area. In the early planning stage, consider carefully how to integrate the new single storey extension with the existing areas of the property.
Before you begin planning, think about your requirements. What are you using the extension for, and how will it work with the rest of your property? You might be extending your kitchen to create a kitchen diner, for example, in which case you’ll be looking for a more open-plan layout. Or you could be adding a home office, which means you’ll need it to be enclosed. Once you know your reasons behind the extension, you will have a much better idea of how it will need to look.