Brentwood Architects
We’re your first step to starting your house extension journey. As a family-run Brentwood architecture firm, we specialise in extensions, offering Building Regulation drawings, structural engineering, and planning support. We can also connect you with trusted, fully insured contractors.
Brentwood's #1
architectural design firm
with the highest number of
5-star Google reviews
A secure home extension design company you can trust
Architectural design services in Essex, packaged just for you
No matter where you are in Essex, we’re ready to assist
Precision-driven architectural design that delivers.
With 5,000+ projects to our name
No fluff, just well designed home extensions
As trusted architects in Brentwood we are known for giving upfront advice you can rely on especially when it comes to build costs and all before you have spent a penny. We offer a complete architectural design service handling everything from house extension plans and planning permission to structural engineering. As your local Brentwood architects we guide you through the entire process and can also connect you with reliable local builders. If you are looking for a team that genuinely cares about getting it right we are here to help.
- Avoid costly build errors
- Access reliable builders
- Prevent council disputes
See what our customers are saying on
Google Reviews
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!!!
Our architectural design services in Brentwood
Kirkwood are experienced Brentwood architects that offer complete architectural design services for homeowners planning to extend or improve their property. From the first sketch to structural calculations and Brentwood planning permission, our house extension planning package covers it all.
Architectural plans & drawings
We create detailed architectural plans tailored to your house extension build budget. Some projects need full building regulations drawings (builder’s working drawings), while others just require house extension plans for planning approval. All our extension drawings are to scale, clearly detailed, and easy to read. Every set of architectural plans is designed to meet Brentwood Council planning requirements.
Planning permission & permitted development
We’ll tell you what kind of application your house extension needs. It could be full planning, a householder application, permitted development or prior approval. Permitted development is the most common in Brentwood, but it still needs council approval and a Certificate of Lawfulness. We sort all the paperwork and speak to Brentwood Council for you.
Building regulations & structural calculations
Every house extension must meet building regulations. We prepare all the technical drawings needed and include structural calculations to support them. These house extension drawings are used for council approval, builder quotes, and the build itself. Building regulations drawings can also be created if needed, but they’re not always required.
Extension planning in Brentwood
We offer a complete extension planning in Brentwood service, covering all your house extension needs. It starts with a quick Zoom call where we advise on what’s possible and give you upfront design and build cost estimates. Think of us as your own human house extension affordability calculator, and the local planning advice is completely free.
Types of house extensions we design
Every extension starts with a smart design and planning, here are the most popular types we work on.
Single storey extensions
A single storey extension is one of the most popular types of home extension in Brentwood. It’s a great way to create a bigger kitchen, add a utility room, or open up the back of the house for that open plan vibe. These house extensions usually don’t need major structural work, which keeps costs down and makes the build quicker. Most fall under permitted development, but they still require house extension drawings and council approval to get a Certificate of Lawfulness. As your Brentwood architects, we design to suit your budget and your needs.
Double storey extensions
A double storey extension in Brentwood gives you serious extra space without doubling your build costs. The ground and first floor share the same foundations and roof, so for twice the square footage, you’re not paying twice. Most people extend the kitchen and living room downstairs, often adding a separate utility room. Then upstairs, you get an extra bedroom, ensuite, maybe even a home office. We design all kinds of layouts, including wrap arounds and side returns that work perfectly with a double storey extension. We’re house extension architects who know the process and the costs inside out — let us help.
Loft Conversions
A loft conversion in Brentwood is a smart move if you’ve got the right loft space. You can add bedrooms, home offices or bathrooms without losing any garden space. We design dormer lofts, Velux loft conversions, and hip to gable layouts depending on your roof and how you want to use the space. Most loft conversions in Brentwood fall under permitted development, but we still submit for a certificate of lawfulness so you’re fully covered. As Brentwood architects, we’re here to make your house extension cost-effective and stress free.
Garage conversions
A garage conversion in Brentwood is a cost-effective way to add usable space. Most garages are too small for modern cars and better used as a bedroom, office, WC, or utility room. These small house extensions are quick to build and fall under permitted development in most cases. As Essex architects experienced in house extension planning in Brentwood, we handle everything to get your garage conversion approved and ready to build.
Kitchen extensions
A kitchen extension is probably the most requested house extension in Brentwood, so we’ve got loads of experience designing both the new extension and adapting the existing layout to make room for it. We’re that experienced with kitchens, we even work closely with Howdens to provide free 3D kitchen designs and big discounts on units and fittings. If you’re looking for advice on open plan kitchen layouts for wrap around, rear or side extensions, our team of Brentwood architects and designers can help.
Wrap around & side return extensions
If you have the space, then a wrap around extension can completely change your Brentwood home. These house extensions open up the whole ground floor, enabling us to rework the layout for things like bigger kitchens, open plan diners and living rooms, and wide glass doors to bring in more natural light. We’re experts when it comes to designing wrap around extensions and adjusting the ground floor area to meet your specific requirements. We already have plenty of wrap around projects under our belt in Brentwood and a long list of satisfied customers.
Local planning permission advice in Brentwood
Planning permission in Brentwood can be straightforward when you’ve got an architect who understands local rules, permitted development, and what paperwork’s actually needed.
Planning permission for house extension
Planning permission rules can vary depending on where you live and what you’re building, but in Brentwood, many house extensions fall under permitted development. That said, certain designs and sizes may still require full planning approval. We check this early and handle the application process for you, making sure your house extension plans meet Brentwood Borough Council requirements without unnecessary delays.
Do I need an architect for an extension?
Brentwood Council require architectural drawings that clearly show your existing property and the proposed house extension layout, along with to-scale elevation drawings. The right type of planning application needs to be selected from the start, and the design should be created around your build cost budget. If the drawings aren’t to scale, builders could make costly errors, leading to disputes or delays. A Brentwood architect will handle all of this, but ultimately, it’s up to the homeowner to decide. You don’t legally need an architect for an extension, but without one, who’s going to produce the plans that meet Brentwood Borough Council’s requirements?
Brentwood Borough Council
We deal directly with Brentwood Borough Council to secure approval for your house extension, handling all drawings, forms, and communication from start to finish.
Permitted Development Rights
Many house extensions in Brentwood fall under permitted development rights. We assess your property, prepare the architectural plans, and submit the right application for approval.
Lawful Development Certificate
Even if planning isn’t needed, we apply for a lawful development certificate so your Brentwood extension is officially approved and protected for the future.
How much does an architect cost for a house extension in Brentwood?
Architect costs for house extensions in Brentwood start at around £1,400 and can reach £3,000 depending on the size and complexity of the job. A small single storey extension under permitted development will usually fall between £1,400 and £1,700. Detached houses are slightly more due to the extra site survey time. The cost of house extension plans is minor compared to the full build, but arguably the most important part. If the design is wrong at the start, the rest of the project can turn into a nightmare, we’ve been called in to fix enough of them. Find an experienced Brentwood architect and start your project on the right foot.
Architect costs for house extensions
Architectural design costs will vary depending on the type and size of your property. Larger homes take more time to survey and produce accurate architectural plans, which affects the overall price. Double storey extension plans tend to be the most expensive, while garage conversion plans are usually the cheapest. If you’re making internal alterations as part of your house extension, this can also increase the cost due to the extra design time involved. As experienced Brentwood architects, we provide clear house extension plans tailored to your layout and budget.
What’s included in our architectural design services
Our architectural design services for Brentwood house extensions include everything you need to get started with confidence. We begin with a full measured site survey of your home, inside and out. Then we create detailed existing and proposed house extension plans, along with any required plan amendments. You’ll also get a design revision consultation to refine your ideas, plus full planning application submission and ongoing management with Brentwood Borough Council.
It don’t stop there
As experienced Brentwood and Essex architects, we handle all council liaison on your behalf to take the stress away. We also offer a free build cost estimate upfront and can connect you with trusted, competitively priced local builders. Whether you’re planning a single storey extension, garage conversion or full double storey project, we make sure every service is tailored to your needs and delivered to the highest standard.
Need help finding a good local builder near you? This guide shares what to look out for and how to avoid costly mistakes.
Kirkwood articles: Expert home extension & renovation insights
Ready to begin your Brentwood project?
Book a Zoom consultation, get free expert advice, and move forward with the next stage – your architectural plans.
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.
Brentwood | Architectural Design & Planning
Postcodes we serve in and around Brentwood
CM13 CM14 CM15 CM5 CM4 RM14 RM3 RM2 RM11 RM12 CM7 CM77
Frequently asked questions
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What services do your Brentwood architects provide?
We offer complete architectural design services for house extensions in Brentwood, including architectural plans, planning permission applications, extension drawings, and structural engineering. We also connect you with trusted local builders.
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Can you help with all types of house extensions?
Yes, we design rear extensions, side extensions, loft conversions, garage conversions, and more. Our plans are tailored to your space, goals, and Brentwood Council’s planning guidelines.
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Do I need to have planning permission before contacting you?
No. In fact, it’s better to speak with our Brentwood architects early. We assess your project, advise if planning permission is needed, and guide you through the entire process from start to finish.
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Can you give advice on house extension costs in Brentwood?
Absolutely. We’re known for giving upfront, honest advice about build costs and potential planning issues before you commit to anything. It’s part of our job to help you avoid costly mistakes.