Rear Extension Builders in Harrow
We design and build rear house extensions for homeowners in Harrow who want more space without moving. From extending kitchens to creating open-plan living areas, our rear extensions are planned, managed, and built with full control from start to finish.
Trusted by local homeowners for high-quality rear extensions across Harrow and North West London.
Service Overview
A rear extension extends the back of your property into the garden, creating additional living space while keeping the existing layout intact. It is one of the most practical ways to increase space and value without altering the front of the house.
Rear extensions are suitable for:
Terraced houses – often built to the full permitted depth to maximise space
Semi-detached homes – single or double-storey rear extensions
Detached properties – larger extensions with greater design flexibility
Common uses for rear extensions include:
Larger kitchen-diners
Open-plan kitchen and living spaces
Family rooms with garden access
Utility rooms and ground-floor WCs
We focus on structural integrity, natural light, and smooth integration with the existing house.
Our Rear Extension Process
Site Visit & Feasibility
We inspect your property, review access, drainage, foundations, and neighbouring constraints. This ensures the extension is practical, compliant, and buildable before work begins.
Design coordination & approvals
We work alongside architects or approved drawings to confirm layouts, structural details, and specifications. Planning and building control requirements are checked before construction starts
Construction & inspections
All structural work is carried out in stages with scheduled inspections for foundations, drainage, steelwork, and insulation. You receive clear updates throughout the build.
Completion & sign-off
Final finishes are completed, building control approval is secured, and the extension is handed over clean, compliant, and ready to use.
Planning Permission & Building Regulations
Many rear extensions fall under permitted development, depending on property type and size:
Terraced houses – up to 6 metres depth
Semi-detached and detached houses – up to 8 metres depth
Older limits of 3 metres (terraced) and 4 metres (others) may apply without prior approval
Planning permission is required if:
The extension exceeds permitted development limits
The property is listed or in a conservation area
Height, boundary, or design rules are breached
All rear extensions must comply with Building Regulations, covering:
Foundations and structural safety
Drainage and damp protection
Thermal insulation and ventilation
Fire safety and glazing standards
We ensure inspections are booked and approvals are obtained at every stage.
Local & Trusted Builders
Serving Harrow & surrounding areas
Rear extension specialists with hands-on construction experience
Strong knowledge of Harrow property styles and ground conditions
Structural steel, brickwork, and drainage expertise
Clear communication throughout the build
Fully insured and building control compliant
Trusted by Homeowners in Harrow
5★ rated on Google by local customers
"LA Construct did a great loft conversion for my family home. Professional from the start, would highly recommend."
- Adrian D, Harrow
"I couldn’t be happier with the work done by LA construct on my bathroom fit-out. From start to finish, the entire process was smooth, professional, and hassle-free. The team was punctual, tidy, and their attention to detail was second to none."
- Darren S, Pinner
"Overall it was top quality with a positive experience and wouldn’t hesitate a minute to recommend Ari!"
- Chandra M, Pinner
Why Choose Us for Your Rear Extension
Trusted Builders in Harrow
Rear extension specialists
We focus on extensions, not general building, ensuring structural accuracy and efficient sequencing.
Controlled build stages
Foundations, steels, drainage, and inspections are managed methodically to avoid delays and issues.
Local knowledge
We understand Harrow planning expectations, property layouts, and access challenges.
Clear communication
You deal directly with the build team, with regular progress updates and site access.
Our Projects
We take pride in delivering high-quality building projects across Harrow and surrounding areas.
Recent rear extension projects in Harrow
How Much Does a Rear Extension Cost ?
Most rear extensions in Harrow typically cost between £1,800 – £2,500 per m², depending on specification.
Costs are influenced by:
Size and depth of the extension
Structural steel requirements
Ground conditions and drainage alterations
Roofing type (flat, lanterns, or pitched)
Level of internal finishes
We provide clear, itemised quotes based on your specific project.
NEED MORE INFORMATION?
Frequently Asked Questions
Answers to some of the most common questions we’re asked about rear extensions.
Do you help with planning permission and drawings?
Yes. We can guide you through the planning process and work alongside architects, structural engineers, and building control where required. If planning permission isn’t needed, we’ll still ensure the extension complies fully with building regulations.
Are you fully insured and building regulations compliant?
Yes. We are fully insured, and all work is carried out in line with current building regulations. Required inspections are arranged and completed at the correct stages of the build.
Will I need to move out while the extension is built?
In most cases, no. Many clients stay in their homes while the extension is being built. We plan the work carefully to minimise disruption and keep the site safe, tidy, and organised.
Do you provide a written quote and clear stages?
Yes. After a site visit, we provide a clear, detailed quote outlining what’s included. We explain each stage of the build so you know exactly what to expect — no surprises
Do rear extensions need planning permission in Harrow?
Not always. Many rear extensions fall under permitted development, but planning permission may be required depending on size, location, and property type.
How long does a rear extension take?
Most single-storey rear extensions take 10–14 weeks, depending on complexity and weather conditions.
How do I get started?
Simply contact us to arrange a free site visit. We’ll discuss your ideas, assess your property, and give honest advice on the best way forward.
Get a Free Rear Extension Quote
Leave your details and we’ll get back to you to arrange a free site visit.
Our Service Areas
We build rear extensions across Harrow, including surrounding areas in North West London.
Call or WhatsApp for a free quote.
Harrow
Stanmore
Northwood
Edgware
Watford
Wembley
Pinner
Ruislip
Greenford
Northolt
LA Construct Ltd
Trusted builders serving Harrow & surrounding areas.
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