Home Extension Builders in Brentwood
Trusted local extension builders in Brentwood (CM13, CM14, CM15) offering complete home extension design, planning, and construction - all handled by Buildaway.
Your Local Home Extension
Specialists in Brentwood
Buildaway treats Brentwood extensions as a sequence: survey, drainage and consent, then structure, then finishes. Party wall notice is required on any semi-detached property here, and the notice periods are handled as part of the contract rather than left to you. Brentwood sits within Buildaway's established CM13 area, with extension projects completed around Brentwood High Street, Weald Country Park and Ongar Road.
Across Brentwood and CM13, Buildaway designs and builds extensions on substantial detached houses, Edwardian villas, and large commuter-belt properties around Shenfield. Regular streets include High Street, Shenfield Road and Kings Road, with Brentwood Cathedral and Brentwood School inside the area.
With a strong reputation for quality workmanship, Buildaway delivers extension design and construction across Brentwood and the wider CM13 area. Whether adding a single-storey rear extension or a double-storey addition, we explain the build cost and programme clearly and deliver structurally sound, well-finished results.
Our Home Extension Packages in Brentwood
Single-Storey Rear Extension
Ideal for expanding your living space. Includes structural survey, architectural drawings, groundworks and foundations, brickwork and roofing, bi-fold or sliding doors, heating installation, building regulation approval.
Side Return Extension (Most Popular)
Complete kitchen and living area transformation. Includes structural assessment, full groundworks, steelwork if required, brickwork and matching materials, glazing and doors, full insulation, electrics upgrade, flooring, building regulation approval, waste removal.
Double-Storey Extension
For those seeking maximum space addition. Includes architectural design, full structural alterations, steelwork and foundations, bespoke staircase, multiple room creation, bathroom or en-suite option, planning and building regulation handling.
Why Brentwood Homeowners Choose Buildaway
Experienced installation teams familiar with CM13, CM14, and surrounding areas
Based in your area with local expertise and reputation.
Bespoke extension designs for family homes, apartments, and countryside properties
We handle everything so you don't have to worry.
Transparent and honest pricing with no hidden fees or unexpected charges.
Clear upfront pricing with no surprises along the way.
Full project management from concept to flawless completion
Meticulous craftsmanship in every aspect of your extension.
Trusted locally, with work completed near Shenfield, Warley, and the Brentwood High Street
Professional consultation and detailed quotes at no cost.
What's Included in Your Home Extensions Services
Everything you need for a seamless, stress-free home extension - from structure to finish.
Full groundworks and structural build
Complete groundwork preparation and structural construction services.
Plumbing, electrics, and heating integration
Professional installation of all mechanical and electrical systems.
Roofing, windows, and external finish
Complete roofing, window installation and exterior finishing.
Plastering, flooring, and decorating
Professional plastering, flooring and decorating services.
Interior fit-out and finishing
Complete interior fit-out and professional finishing touches.
Project management and schedule control
Professional project management and timeline control throughout.
What Our Clients Say
Real reviews from our satisfied customers.
“In half an hour he was at the door ... he listened and then checked, measured and said to me it is doable. Cormac is very good with communication, listening, advising, a hard worker and an excellent team leader. I am extremely impressed, happy and proud of what his team delivered.”
Betty Lwanga
Verified Google review
“From the moment I contacted Cormac, I knew I was in good hands ... What really impressed me was Cormac's honesty. He was upfront about what would and wouldn't work with my space ... They were on-time every day and completed the job in the agreed two weeks.”
Nana A.
Verified Google review
“From start to finish the experience was smooth and well organised. Cormac was easy to deal with, communication was clear and everything ran to the agreed timelines ... The quality of the finish is excellent. The bathroom looks fantastic and the bedrooms feel completely refreshed.”
Helen Sivyer
Verified Google review
“From my first contact with Cormac, I was in good hands. His team turned my vision into reality, communicating with me every step of the way and offered helpful suggestions which turned my bathroom into an oasis. I could not be happier and would highly recommend their services.”
Jackie Brown
Verified Google review
“We've had a genuinely fantastic experience with Buildaway. Cormac was ultra responsive and excellent at communicating with us throughout our project. The quality of the work was excellent ... Friendly, reliable and also competitive.”
Kiran Collier
Verified Google review
“After meeting with Cormac, we were confident that he understood our requirements and could achieve the design we proposed. He gave a detailed and competitively priced quote ... He communicates well, and works with you, offering advice and suggestions. We now have a fantastic new bathroom.”
Garry Knight
Verified Google review
Frequently Asked Questions
Your questions about home extensions in Brentwood, answered.
Do I need planning permission for an extension in Brentwood?
Many single-storey rear extensions fall under permitted development, but that changes inside Brentwood Town Centre Conservation Area and Metropolitan Green Belt boundaries, where allowances are materially tighter. Buildaway establishes which category your CM13 property falls into before drawing anything.
What is a build-over agreement and will I need one?
If the extension crosses a public sewer you need written consent from the water authority before building over it. It is common in Brentwood because of how rear drainage runs. The application takes several weeks, so Buildaway starts it at design stage rather than letting it delay the build.
How long does a rear extension take to build?
A single-storey rear extension is generally ten to fourteen weeks on site once foundations start, depending on glazing lead times. Double-storey work runs longer. Buildaway separates the design and consent period from the build period on the programme so expectations are realistic.
Do you handle drawings and building control?
Yes. Buildaway coordinates structural calculations, the building control application and inspections, and manages the party wall process where a neighbouring wall is affected, which is frequent on Brentwood semi-detached properties.
Will an extension affect my neighbour?
On any semi-detached or terraced Brentwood property the Party Wall Act applies and notice must be served. Buildaway handles the notices and statutory periods, and factors them into the start date rather than discovering them mid-project.
Get Your Free Quote
Tell us about your project and we'll get back to you within 24 hours.
We Serve Brentwood and Surrounding Areas
Based locally and working across Brentwood and the neighbouring CM13 streets every week.
Ready to Transform Your Extension in Brentwood?
We’ve transformed extensions across Brentwood, from period homes to modern new-builds - always delivering high-end, lasting results.