Extensions
We build extensions from the first dig to the final coat of paint, one contractor for groundworks, structural work, roofing, first and second fix, and finishing. That covers single and double-storey extensions, rear, side and wraparound additions, garage conversions and loft conversions. Most of our extension clients come to us because they've outgrown their house but don't want to move.
What's included
How we approach it
One contract, start to finish
No handing off between separate groundworkers, bricklayers and finishers. We manage the trades and the programme so you have one point of contact throughout.
Planning and building control handled
We work with your architect or ours, and deal with building control inspections and sign-off as part of the job, not as an extra.
Matched to the existing house
Brick matching, roofline and window proportions are agreed up front so the extension looks built, not bolted on.
Wondering what your extension might cost?
Use our calculator for a rough price range based on jobs we've actually built.
What this covers
The types of work this includes
Single-storey extensions
Kitchen-diners and garden rooms, usually finished with bifold or sliding doors onto the garden.
Double-storey extensions
The most efficient way to add a bedroom while also extending the ground floor beneath it.
Rear extensions
Opens the back of the house onto the garden without touching the front elevation or off-street parking.
Side extensions
Fills the gap down the side of the house for a wider kitchen, utility room or downstairs WC.
Wraparound extensions
Combines rear and side into one L-shaped, open-plan kitchen and living space.
Garage conversions
Turns an underused garage into a proper room, insulated and damp-proofed as standard.
Loft conversions
Adds a bedroom or two in the roof space without extending the footprint of the house at all.
Recent work
Related projects
Upper Caldecote, Bedfordshire
Rear extension, kitchen & bathroom, Taddy Close, Upper Caldecote
Ayot St Lawrence, Hertfordshire
Extension, Ayot St Lawrence
Biggleswade, BedfordshireOn site
Single-storey rear extension, Holly Close, Biggleswade
Sandy, Bedfordshire
Rear extension and garage, All Saints Way, Sandy
From the blog
Related reading
Extensions
Lawful Development Certificate: is it worth getting for your extension?
If your extension is permitted development, a Lawful Development Certificate gives you that in writing. Here is when it is worth it.
Extensions
Building regulations approval explained: full plans, building notice and inspections
Building regulations are separate from planning. Here is how approval works, what gets inspected and why you need the completion certificate.
Extensions
The Party Wall Act explained: what to do before you build an extension
If your extension touches or sits close to a neighbour's wall, you may need to serve notice. Here is how the process works.
Extensions
Can you build an extension over winter? What an autumn start looks like
An autumn or winter start can work well if the programme is planned around the weather. Here is how it usually goes.
Extensions
Get a rough price for your extension with our new cost calculator
We've built a calculator that gives you a rough price range in under a minute, built from rates we actually charge, not generic industry averages.
Extensions
Extend or move? The costs people forget when they compare
An extension looks expensive until you add up what moving actually costs. Here is how to compare the two properly.
Advice
How to choose a builder in the UK: 10 checks before you sign
Ten checks worth making before you sign anything, from insurance and trade body membership to payment stages and visiting a finished job.
Extensions
Planning permission for extensions in Bedfordshire, explained
What permitted development actually covers, when you need full planning permission, and how long each route realistically takes.
Extensions
Loft conversion or extension: which adds more space for your money?
Both add a room without moving house. Here's how they actually compare on cost, disruption and the space you end up with.
Extensions
How much does a single-storey extension cost?
A realistic breakdown of what drives the price of a single-storey extension up or down, based on jobs we've actually quoted and built.
Questions
Frequently asked questions
Do I need planning permission for an extension?+
Many single-storey rear extensions fall under permitted development and don't need full planning permission, but it depends on the size, your property's history and whether you're in a conservation area. We check this with you before any design work starts, and can apply for a Lawful Development Certificate if you want it in writing.
Do double-storey extensions need planning permission?+
Almost always, yes. Double-storey extensions rarely qualify for permitted development because of overlooking and privacy rules for upper floors. We prepare and submit the application as part of the project.
How long does a typical extension take?+
A single-storey rear extension is usually 10 to 14 weeks from groundworks to completion. A double-storey extension or one with a more complex roof can run to 16 to 20 weeks. We give you a realistic programme before work starts, not a best-case guess.
Can I stay in the house while the extension is built?+
Yes, most of our clients live in the house throughout. We agree access, dust control and working hours with you up front, and keep you updated as the job progresses.
Can you match the extension to our existing brickwork?+
In most cases, yes. We source matching or close-matching brick and agree this with you at quote stage, particularly important on older properties where the original brick is no longer made.
What happens if the extension is built over a drain?+
We carry out a drainage survey before the quote is finalised. If a manhole or run needs relocating, building control has specific rules for building over drains and we design to meet them.
How much head height do I need for a loft conversion?+
Building regulations generally require at least 2 metres of head height above the stairs, though a lower ridge can sometimes be raised or a dormer added to achieve this. We measure this on the first site visit.
Where we work
Where we have done this work
Get in touch
Request a quote
Tell us about your project and we'll come back to you to discuss it in more detail.
Prefer to talk it through first? info@jlsbpd.com