Smartly Designed House Extensions in Chelmsford
Start your Chelmsford home extension with expert architectural plans, full planning support, and trusted local builder connections.
Chelmsfords's #1 house extension
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Chelmsfords's #1 house extension architectural design firm
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Based in Brentwood, Essex, we were also introduced to builders and tradespeople through Kirkwood, and they were excellent—professional, respectful, and a pleasure to work with. If we ever take on another project, we wouldn’t hesitate to use them again.
We now have an amazing extension, and would be happy to use the team again.
Very knowledgeable and contactable throughout the process.
Couldn't ask for a better outcome and value for money.
Will definitely be recommending and 100% will use again!
5 star!!!
Single storey house extensions remain one of the top choices for Chelmsford homeowners. They’re an affordable way to gain extra living space and come with plenty of layout possibilities. You might want to expand your kitchen, design an open-plan kitchen diner, add a utility room to free up space, or build a new office with a shower room. There’s a lot you can do. Most single storey extensions in Chelmsford fall under permitted development, but formal approval is still required. These types of Chelmsford house extensions are what we’re known for. Talk to us about your ideas and we’ll help you plan what’s achievable.
- Avoid costly build errors
- Access reliable builders
- Prevent council disputes
How a Single Storey Extension Can Transform Your Chelmsford Home
A single storey extension can completely change how your Chelmsford home works and feels on a daily basis. It’s hands down the best way to gain a larger kitchen. Most homeowners now want that open-plan kitchen diner setup, and with kitchens usually located at the back of the house, extending there makes perfect sense. Many Chelmsford homeowners use this kind of house extension to add a downstairs WC or make space for a utility room. As Chelmsford architects and experienced Essex architects, we know how the right kitchen design can transform a home. Add roof lights and wide glass doors, and you’ve got a house extension worth showing off.
For modern inspiration, take a look at our contemporary single storey extension guide.
Planning and build costs for single storey extensions in Chelmsford
Knowing how much a single storey extension in Chelmsford costs makes it easier to decide if the project fits your budget. That’s why we guide homeowners on build costs right from the start. We begin with a Zoom call to talk through your ideas, then give you our architectural design fees along with estimated build costs. A 3 metre house extension is one of the most popular choices, especially as it can fall under permitted development. Even so, every extension still needs accurate plans and the right approvals. Full planning permission isn’t usually required, but we always recommend applying for a Certificate of Lawfulness before building begins. As experienced Chelmsford architects and leading Essex architects, we’ll walk you through the planning process, council requirements, and typical timescales for Chelmsford house extensions.
Learn more about permitted development
Why single storey extensions are a smart choice in Chelmsford
Many homes in Chelmsford are ideal for a single storey extension, particularly those with good space at the rear or side. These properties often suit an open-plan kitchen diner or a 3 metre house extension that falls under permitted development. A carefully planned home extension in Chelmsford can completely change how the ground floor works. Chelmsford house extensions are most successful when tailored to how you actually use your space. Choosing the right local architect for extension planning in Chelmsford helps prevent costly mistakes and avoid issues with the council. Avoid full planning where possible and speak to our team for practical advice.
For more ideas, take a look at our Top 5 Inspiring Single Storey Extension Ideas for Your Home
Why choose Kirkwood for your house extension in Chelmsford
Every member of our team genuinely cares about delivering a 5-star service. It started with our founder and naturally brought in skilled professionals who share the same values. Our fees offer strong value, with competitive pricing backed by high-quality results. We’ve built up extensive experience working with councils across Essex, which helps secure approvals and avoid delays. From the start, we advise on build costs and provide every service needed for a smooth extension project. Not many Chelmsford architects do that, for more help, take a look at our article on finding the right architect for your Chelmsford home extension. We’re also careful about the builders we recommend. They need to be fairly priced, experienced, and reliable. When it comes to Chelmsford house extensions, we only work with trusted teams.
Planning Permission & Permitted Development
As full-service Brentwood architects, we design to suit your build budget and avoid surprises later. Our extension plans cover layout ideas, building regulation drawings, and structural calculations all in one.
Architectural Design & Extension Plans
As full-service Chelmsford architects, we design around your build budget to help avoid unexpected costs later. Our extension plans include layout options, building regulation drawings and structural calculations all in one.
Build Costs & Trusted Builders
Before you spend anything on your Chelmsford house extension, it’s important to understand the full costs, especially the build cost. We arrange a Zoom call early on to talk through what to expect and how everything adds up.
Popular types of house extensions in Chelmsford
There’s no one-size-fits-all when it comes to Chelmsford house extensions. Everyone’s needs are different, and that’s where our experience as Chelmsford architects comes in. We’ve designed every type of home extension, from compact 3 metre rear extensions to large double storey builds with loft conversions above. We advise on build costs, planning permission, and all extension planning in Chelmsford. If your project needs permitted development approval, structural calculations or building regulations drawings, we’ve got you covered.
Single storey extension Chelmsford
A single storey extension in Chelmsford is still the go-to choice for many homeowners—and it’s easy to see why. It’s fast to build, cost-effective, and ideal for adding a new kitchen, home office, utility room or WC. We’ve helped families across Chelmsford transform their homes with single storey house extensions. Most fall under permitted development, but we handle all the paperwork to make sure your approval is secure. If you’re asking how much a house extension costs per metre squared, we can give you realistic estimates early on so you avoid overspending. As trusted Chelmsford architects, we support you with building regulations and full extension planning in Chelmsford.
Double story extensions Chelmsford
A double storey extension in Chelmsford gives you the kind of extra space that feels like a whole new home—without the hassle of moving. Whether built to the side or rear, these house extensions add serious square footage, often allowing for a larger kitchen, open plan living, utility room and an extra bedroom with en-suite. As experienced Chelmsford architects, we’ve worked on every type of double storey extension, including side returns and wrap arounds. They offer great value by sharing the same foundations and roof across two floors. We guide you through everything from initial house extension ideas to full extension planning in Chelmsford, ensuring your design meets building regulations and is well set up for approval. If you’re asking how much a house extension costs in Chelmsford, we’ll give you clear answers and expert advice early on.
Rear extensions Chelmsford
Rear house extensions in Chelmsford are one of the most popular home extension types we design, especially when there’s a decent sized garden to work with. These house extensions are ideal for building a large open plan kitchen diner, and if the house is wider than 8 metres, you can usually fit in a living room extension too. Most kitchens sit at the back of the house, so it makes sense to extend from there. A lot of our Chelmsford house extensions fall under permitted development rights, but we still submit the paperwork for approval. As experienced Chelmsford architects, we design to match your current layout while also bringing in new ideas that suit how you live. If you want to know how much a rear extension costs in Chelmsford, we go through realistic figures with you on a free consultation.
Not sure which roof style suits your project? Read our pitched roof vs flat roof extension guide to help you decide
Kitchen extensions Chelmsford
A kitchen extension is one of the most popular types of Chelmsford house extensions we design. Since most kitchens are at the back of the house, it makes them ideal for single storey kitchen extensions that open out into the garden. With more people working from home, the kitchen has become the heart of the house, so making it bigger and more enjoyable to be in is a smart move. That’s not just our opinion, it’s what we hear from homeowners we’ve worked with on house extensions in Chelmsford. We’ve designed hundreds of kitchen extensions in the area, often using rear or wrap around layouts to get the most from the space. As trusted Chelmsford architects, we provide a full design service that covers everything from layout ideas to building regulations and Chelmsford council approvals. We also guide you through kitchen extension costs and give honest advice based on your home and budget.
Loft conversions in Chelmsford – Use every corner of your home wisely
A loft conversion is a smart way to gain extra living space without needing to build outwards. In Chelmsford, many detached and semi detached homes with pitched roofs are perfect for this type of house extension. As experienced Chelmsford architects, we design all kinds of loft conversions including dormer, Velux, and hip to gable layouts. We handle everything from your home extension plans to submitting the application to Chelmsford Council under permitted development or planning if needed. If you want to know how much a loft conversion costs in Chelmsford, speak to our Essex architects for expert advice.
Do You Need Planning Permission?
Most Chelmsford loft conversions fall under permitted development, but we still apply for a Certificate of Lawfulness.
How Much Does a Loft Conversion Cost?
Dormer loft conversions in Chelmsford start at £45,000. We guide you on costs from the start.
Types of Loft Conversions in Brentwood
We design dormer, hip to gable, and Velux loft conversions in Chelmsford to suit your layout and roof.
Garage conversions in Chelmsford
Affordable extension
If you have a garage that’s not being used properly, converting it could be one of the most affordable ways to add extra space. Most garages aren’t much use for parking these days, especially with the size of modern cars. A garage conversion in Chelmsford turns that wasted space into something practical, like a home office with a shower room, a snug, a gym, a spare bedroom, or a utility area to free up space in the kitchen.
Garage conversion costs
Usually, garage conversions in Chelmsford fall under permitted development rights, so it’s rare to need full planning permission, but it still depends on the property. If your home is in a conservation area or if the front of the garage is being extended forward, a different type of application may be required. We check all of this for you and deal with Chelmsford City Council on your behalf. The build usually takes around four to six weeks, and garage conversion costs typically start at around £15,000, rising to £25,000 or more depending on the size and specification. An experienced Chelmsford architect can prepare your garage conversion plans and submit them for approval if needed.
House extension planning in Chelmsford
When planning a house extension in Chelmsford doesn’t need to be complicated. For us, it’s a clear process that follows steps we’ve handled many times before. It takes a solid understanding of planning permission, permitted development rights, building regulations, build costs, and more. These are all things an experienced Chelmsford architect should be confident with. We seek approval for all Chelmsford house extensions, even a 3 metre house extension under permitted development, as every project still requires some form of permission. Whether it’s a single storey extension or a larger double storey build, the process can still be simple when you’ve got the right team on your side.
How much does a house extension cost in Chelmsford?
The first things Chelmsford homeowners want to know is how much a house extension costs, and for good reason. It’s smart to understand the affordability before investing in architectural plans. As experienced Chelmsford architects, we guide you on build costs right from the beginning. Our process starts with a free Zoom consultation where we talk through your ideas and provide estimated build costs and exact design fees. Whether you’re planning a 3 metre house extension under permitted development or a larger two storey extension, we make sure you have clear, realistic figures before taking the next step.
Cost per square metre for house extensions in Chelmsford
On average, the cost of a house extension in Chelmsford starts from around £1,900 per square metre. That figure usually covers the main build but doesn’t include finishes like flooring, decorating, or a new kitchen. For a 3 metre single storey extension measuring 3 by 5 metres, you’re looking at roughly £30,000 to £35,000 plus VAT. If you add features like electric roof windows, external lighting, or a full kitchen installation, costs will go up. We guide you through all of this early on to make sure your Chelmsford house extension matches both your budget and your goals.
What affects the price of a house extension?
Multiple things impact how much a house extension costs in Chelmsford. Size is one of the biggest factors. Extensions over 20m² usually sit around £2,000 per square metre, while smaller builds can push that rate higher. Foundation type can also affect cost—piled foundations for house extensions might add £10,000 or more depending on the scale of the project. As experienced Essex architects handling extension planning in Chelmsford, we talk you through all the key factors so you don’t get caught out by unexpected costs.
Home extension cost calculator
Still wondering how much an extension costs in Chelmsford? Use our free design cost calculator. It gives us the key details we need to send you an estimate based on your extension size, type, and location. It only takes a few minutes to complete and helps us give accurate build cost advice for house extensions in Chelmsford. For more tailored guidance and a quote, book a free call with one of our Chelmsford architects today.
Ready to start your home extension in Chelmsford?
If you’re planning a home extension in Chelmsford, Kirkwood is here to help. The experienced team provides guidance through every stage, from architectural design to securing planning permission with Chelmsford City Council. Whether it’s a loft conversion, garage conversion, or kitchen extension, designs are created to maximise space, comply with building regulations, and enhance the home.
Get in touch by emailing info@kirkwoodbuild.co.uk or phoning 01268 944233 to schedule a free consultation. Let’s turn your ideas into a well-designed, approved, and beautifully planned extension.
