Open plan kitchen diner extension with a vaulted ceiling and a glazed gable opening onto the patio

House Extensions in Chelmsford

Extensions designed around how you use the space, built by a team that handles the whole job from start to finish. Working in Chelmsford and the surrounding area.

Tell us about your project Call 07792 625391

SET Building & Brickwork builds house extensions in Chelmsford and the surrounding parts of Essex. We price every job after a visit to the property.

The extra space you have in mind

Whether it is a bigger kitchen diner, a playroom or a bedroom downstairs, we can help you get the space your family needs. We help with the planning and drawings, and with over 15 years in the trade we will tell you straight what works on your house.

Planning and drawings sorted with you
Building control inspections booked
A written quote, priced from a site visit

Extension builders in Chelmsford

Moving costs more than most people expect, and the right extension buys you the room you are short of. Whether you are in Chelmsford itself or nearby in Great Baddow, Springfield or Broomfield, we will look at what your house and plot allow, price it properly, and build it so it looks like it was always there.

What your extension can include

Single storey and double storey extensions
Side return and wrap around extensions
Kitchen extensions and open plan kitchen diners
Structural steels and load bearing openings
Brickwork, blockwork and matched facing brick
Flat and pitched roofs, rooflights and roof lanterns
Bi-fold doors, sliding doors and windows
Plumbing, electrics and first and second fix carpentry
Plastering, flooring and decoration
Building control inspections through to sign off

Extensions and open plan rooms from our recent jobs.

Open plan kitchen and lounge under a skylight — Open plan kitchen and lounge

Single storey brick extension with black bi-folds and a roof lantern at dusk — Brick extension, bi-folds and roof lantern

Open plan kitchen diner with a dark island, glass pendant lights and a roof lantern — Kitchen island and roof lantern

Black sliding doors across a rendered back wall at dusk — Sliding doors at dusk

Sage green island with rattan bar stools, black pendants and a roof light — Island with bar stools

Back of a white rendered house with bi-fold doors opening onto a new lawn — Bi-fold doors onto the garden

Planning rules in Chelmsford

Planning applications in Chelmsford go to Chelmsford City Council. The council has 26 conservation areas, nine of them in the city itself, including Moulsham Street and the West End.

If your house is in a conservation area, such as Moulsham Street or the West End, side extensions and two storey rear extensions are not permitted development and need a planning application.

Some jobs need a full application and some fall under permitted development. We tell you which applies before you pay for drawings, and build to your architect's and structural engineer's drawings.

Building control in Chelmsford

Building regulations are signed off separately from planning. Where your extension needs building regulations approval, we book the inspections with Chelmsford City Council or an approved inspector and see it through to the completion certificate.

Speak to us about your project today or call 07792 625391

Questions about house extensions in Chelmsford

How do I get a quote?

Whichever suits you best: call us on 07792 625391, message us on WhatsApp, or fill in our short enquiry form. We will arrange a time to come and see the property, then put a written quote together.

Do I need planning permission for an extension?

It depends on your property, its position and what has been built there before. Some extensions fall under permitted development and others need a full application. We will talk you through which route looks likely before you commit to anything.

How long does an extension take?

It depends on the size of the build and the specification. We give you a realistic programme before work starts and keep you updated if anything changes during the project.

Recent projects

Clips and photos from our own jobs across Essex and east London. See all our work.

Oak framed porch and driveway — Oak framed porch

Black weatherboarded bungalow with clay tiles, an oak framed porch and a block paved driveway — Black weatherboarded bungalow with an oak porch

Steels, brick piers and joists in place

White rendered detached house with clay tiles, black sash windows and an oak framed porch — Rendered house with an oak framed porch

Double vanity on a rustic timber washstand, with arched mirrors and a walk-in shower behind — Double vanity and walk-in shower

Blockwork, steels and new joists going up

Oak shaker kitchen with a hob island, marble-effect worktops and brass pendant lights — Oak shaker kitchen with a hob island

Walk-in shower with twin rain heads, a lit niche and a pebble floor — Walk-in shower with twin rain heads

Palm print feature wallpaper above white wall panelling, with a toilet and bath — Feature wallpaper and wall panelling

Rendered detached house lit up at night behind a rendered front wall — Rendered house lit up at night

Dark oak kitchen with a curved ripple island — Dark oak kitchen with curved island

Walk-in shower and oak vanity in a marble tiled room — Marble bathroom

White fluted tiles and a rain shower against a green wall — Tiled wet room

Green herringbone tiles, an arched mirror and an oak shelf — Herringbone tiled cloakroom

More clips on our Instagram

What our customers say

Reviews left on our Google profile.

We couldn’t be happier with the work Shaun and his team done for us! From the extension through to the internal refurbishments, everything has been completed to a really high standard with great attention to detail…

Casey Whitlock July 2026 Posted on Google

Shaun and his team have carried out a large extension for me at Chelmsford over the last 5 months. Was impressed at how quick his team completed the work. Skilled and experienced on groundworks, brickwork, structural steelwork, roofing and driveways. Has managed the project well and given us honest advice throughout. Very grateful to have found a building company we can trust, at a competitive price. Recommend 100%

Steve Massey September 2026 Posted on Google

We had a fantastic experience with Set Building and Brickwork during our house renovation. From start to finish, they were professional, supportive, and always willing to provide helpful guidance. Their experience and expertise were evident…

Madison Harris July 2026 Posted on Google

We couldn’t be happier with the work Shaun. He completed a self-contained annexe, and a single storey extension on our main house reconfiguring the downstairs layout of our home, and clearing and levelling the garden…

Jamie Harbour September 2026 Posted on Google

Shaun completed a double storey extension on our house and couldn’t recommend SET builders enough, great communication throughout the process and we’re very happy with the outcome of our build.

Sarah Perfect September 2026 Posted on Google

We recently had renovation and alteration work done at our home, and I can’t recommend this team highly enough. From start to finish they did a fantastic job. The lads were polite, respectful, and kept everything clean and tidy throughout…

Rita McGee September 2026 Posted on Google

I honestly couldn’t recommend Shaun at Set Building and Brickwork enough. He was…

Zoe Tate September 2026 Posted on Google

Quality job, tidy and competent

Lewis Barr September 2026 Posted on Google

House extensions near Chelmsford

We also take on loft conversions in Chelmsford, kitchen renovations in Chelmsford and house renovations in Chelmsford. For everything else we do locally, see builders in Chelmsford.

Talk to us about your extension

Tell us about the property and what you are looking to do, and we will arrange a visit.

Tell us about your project Call 07792 625391