Trimble Architects

RIBA Architectural Services

Phone Number: 020 8538 9303

Mobile Number: 07785711635

Are you looking for single storey extension architects in London? Our RIBA local architect services works throughout Hounslow, Twickenham, Richmond, Kingston Upon Thames, Teddington And Throughout London.

Single Storey Extension

Suppose you've come to outgrow your current home, and you're desperately searching for ways to remodel or add value to your home to make it more inviting. 

The single-storey extension might be an excellent solution that ticks numerous boxes. Trimble Architects Ltd has fantastic architects working throughout South, North London and Surrey boroughs, such as Merton, Croydon, Kingston, Lambeth, Kensington and Chelsea, Elmbridge and Wandsworth. We'll complete wraparound builds and single-storey extensions of all kinds to suit your dream home and desires.

single storey extension architects

A single-storey extension may be precisely what you need to allow plenty more room to re-design your space, making for an excellent solution for those that want a dining room, kitchen or bathroom extension to expand your existing home. 

These additional spaces can bring friends and family together with more open living plans and thoughtful design with the help of our fantastic, qualified professionals to guide you through the process. 

A single-storey adaptation can become a statement asset of a home and create stunning transitions outside into your garden, fun areas to entertain and host parties with friends and family.

Our top-tier team of in-house professionals will work closely with you to design stunning single-storey extensions. They will provide all the essential advice on planning permission and building control to ensure all parts of your project match your local area's regulations for necessary approval. 

Ensure your desired flat pack extension build isn't within a conservation area or a listed building. You can still gain permission, yet it might be more challenging to obtain, as these areas are generally protected.

We have good architects on board who will act as dedicated project managers for the new build extension right through to completion with all the skills, equipment and high-tech tools. 

It will allow you and your local councils or planning consultants to observe your project as realistically as possible before the construction or even before you fully commit to it. We have the high-quality technology to transform your building drawings into 3D Visualisations so that we can genuinely see how the extension will look more immersively.

Regardless of the extension you're after or interested in adding to the side or rear of your London or Surrey house or property, Trimble Architects is here to provide apt house extension design ideas to adhere to your style and the guidelines of the area. 

Contact us today for a free quote. We'll discuss your ideas for building an extension and curate ideal and suitable building floor plans with a site visit to your home to better understand what you want, alongside the necessary measurements. 

A site visit is essential for architects, structural engineers and builders so that we can assess the area. If there is any uneven terrain or building constraints, we'll need to curate the most suitable groundwork plan and soil types so your project can be completed to a high standard.

How much is the total cost of building a Single Storey extension?


Extending your home can be a hefty job, especially when there are so many aspects to consider and decisions that will affect the entire process before proceeding with the new extension. 

There are a whole host of rules and regulations that we encourage you to follow so that you can go ahead and dive in. The house extension cost varies depending on various important factors, for example, the use and the extension size you desire. Much smaller and less complex site extensions are typically the most affordable.

Those wishing to implement single-storey extensions can expect the lowest end of the price range to cost approximately £1,000-£1,600, a mid-range might be around £1,700-£2,000, and the more luxury/high-end extension plans can expect to pay around £2,200-£4,000, alongside any additional costs for installations.

Ideas for Single Storey House Extensions

You can utilise a new single-storey extension for your original household in many ways, and our Trimble architects are blessed with immense creativity and innovation. They can provide all the best ideas to enhance your home project in a suitable, practical, stylish, and visually pleasing way.

Two of the most popular ways to go about a single-storey extension is to turn them into either kitchen or wraparound extensions.

Kitchen Extensions


The heart of the home is typically considered to be the kitchen, as many adults will spend at least an hour or more in this part of the property preparing food or chatting, as the kitchen is quite favoured among the other rooms of the property for most Brits. 

Its importance is often why kitchen extensions are one of the most popular uses of the single-storey rear extension for homeowners across the UK.

For those who wish to invest in a single-storey extension to expand your kitchen space, it will allow you to curate a brand-new, updated and vibrant design, enhancing the potential of your household overall. 

A single-storey house extension is a building type under the permitted development rights, making it incredibly easy to create an accessible open space that works best for you and your household, practically and visually.

However, before gathering builders and surveyors, you'll want to ensure you obtain a party wall agreement. Party wall agreements are vital for building any project affecting the adjoining properties, meaning any neighbouring buildings and individuals. 

In recent years, the rules of planning an extension have been relaxed; however, even those households and terraced houses with Permitted Development rights will still need proof of a party wall agreement. Warning those in your community about the new developments is essential so that they are aware of any off-road parking and disruptions.

Trimble Architects Ltd has a fantastic extension architecture team skilled at designing open spaces and can bring all your ideas to life. We'll work with you to ensure your new build layout plans and drawings match the criteria to gain the necessary planning permission and your budget whilst adding luxurious touches to enhance your vision. 

We're experts in kitchen design and extensions; with our collaborative team's professional experience, we're guaranteed to deliver high-quality, top-tier services.

Wrap Around Extensions


We would encourage you to take your single-storey rear extension perhaps a step further and begin designing a wraparound extension for your household or property. 

Such extension will allow you to create more flexible living spaces to suit any occasion and incredible openness. Generally, the wraparound extension wraps itself around the existing structure to form an 'L-Shape.' 

However, please be aware that you, the householder, must complete planning applications and receive approval from your local council or authority before proceeding with construction.

Contact us at Trimble today if you require assistance filling out your planning application or need any plans assessed to see whether they would be approved based on your area's criteria and building regulations. Our trusted professionals can visit and look at your plans, giving in-depth advice and any help you need.

London and Surrey wraparound single-storey extensions are one of the most innovative ways to create more space in your home and add further value to your household without fear of financial burdens. 

It provides homeowners with lots of natural light and sufficient open living arrangements, considered two of the potential buyers' and homeowners' top 10 most desirable living features for those moving home, alongside loft conversions and other home improvements. 

It can offer many benefits; it adds significant value to your building at lower construction costs. Still, compared to loft extensions or double-storey extensions, the number of space per square metre you can gain from a single-storey wraparound is truly impressive.

Frequently Asked Questions about Single Storey Extensions

Deciphering the general build cost of your single-storey rear extension is one of the most challenging aspects of any new build or extension project. You'll find the other aspects, like planning and designing, can be pretty fun and exciting. The overall price will typically depend on many factors within your briefs, such as labour, square metres and material costs.

However, various general costs of building a single-storey extension at the rear can be summarised within the following price ranges:

UK Average Square Metres: £1,200
London Average Square Metres: £1,400

These are examples of the general costs for a standard extension within the UK and London; the capital cities of any country or continent will always be costly no matter the service you're after, which explains the excessive London costs. Higher-end extensions in London and the surrounding areas can go up to around £2,300 square metres.

Much like any other build, its use will dramatically impact the costs involved, so it's best to have a general idea of the class or use of build your extension fits into. 

During the planning stage, you want to curate an idea of how much you wish to spend on a brand-new kitchen, bathroom, living room or bedroom extension for your single-storey. Typically, the kitchens and bathrooms are the most challenging to budget as you must consider and implement the final costs of drainage plumbing, all the appliances and fitted joinery. 

The cost of installing kitchen compartments, plumbing and appliances like gas meters into your extension will be around £10,000 for the cheapest designs.

The final price will typically depend on the overall quality of the appliances and materials you wish to have installed, such as bespoke flooring like engineered wood floors, light fittings, brand-new appliances, or simply painted walls. Often, the most cost-effective ways of extension are a tad more costly than the generally cheaper options but offer an incredibly long lifespan.

To add a bathroom to your extension project will mean the cost is significantly increased by approximately £5,000, yet the price could get higher depending on the finishes you desire.

The general rule of thumb for budgeting any extension, whether one or two-storey extensions:

Architects throughout London typically take up 10% of your budget. The administration and other professional fees will often take up 1%, and your structural engineer will take approximately 4%. 

Your quantity surveyors will, on average, take around 3%, and your contractors will take up 30% of the budget. The materials used will amount to 20% of the final budget, with the fittings and glazing of windows and doors taking up 5% and 15%, leaving a final 20% for the VAT. 

You must assess your desired building works against the final budget finish, as this will often help decipher which extension style and bespoke options are best for your household and the costs you can afford.

You can extend along the side and separately at the rear without receiving any planning permission, as this is considered under permitted development.

It's paramount that any single-storey rear extension cannot simply extend beyond the rear wall of your current home by any further than 3 metres for a semi-detached house or, if your current home is a detached house, no further than 4 metres. 

Similarly, the maximum height of your single-storey rear extension must not proceed further than 4 metres; otherwise, you'll find that you will require planning permission.

Any side return extensions tend to fall under permitted development, as long as they do not extend more than half the width of the existing house. As long as it is a single-storey extension, you can extend to a maximum of around 3 metres but cannot pass the front elevation.

Nationwide has conducted a lot of research showing us how home extensions and other home improvements can drastically add value to your property that you may not have even considered. 

Single-storey household extensions can add approximately 23% value to your initial existing property. 

Trimble Architects

Based in Twickenham

South West London

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If you require help and advice from our single storey extension architects get in touch today. Trimble Architects are based in Twickenham and work across south-west London.

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