Side Extension Builders in Harrow
We design and build side house extensions for homeowners in Harrow who want to unlock unused space at the side of their property. Our side extensions are carefully planned to improve layout, add floor area, and integrate seamlessly with the existing house.
Trusted by Harrow homeowners for well-managed, structurally sound side extensions.
Service Overview
A side extension extends your property into unused side land, typically where there is a garage, alleyway, or wide side access. Side extensions are an effective way to increase internal space without reducing garden depth.
Side extensions are suitable for:
Semi-detached houses – the most common type for side extensions
Detached homes – allowing for wider or wraparound layouts
End-of-terrace properties – where side access is available
Common uses for side extensions include:
Enlarged kitchens or kitchen-diners
Additional reception rooms
Utility rooms and storage spaces
Downstairs bathrooms or WCs
Side extensions are often combined with internal reconfiguration to improve flow and usability.
Our Side Extension Process
Site Visit & Feasibility
We assess boundary positions, access width, drainage runs, and neighbouring structures to confirm what can be built and how it will affect the existing house.
Design coordination & approvals
We review architectural drawings, structural details, and planning constraints to ensure the side extension meets local requirements before work begins.
Construction & inspections
Work is carried out in defined stages, with inspections for foundations, structural steel, drainage connections, and insulation. Progress is clearly communicated throughout.
Completion & sign-off
Final finishes are completed, building control sign-off is obtained, and the extension is handed over fully compliant and ready for use.
Planning Permission & Building Regulations
Side extensions are more likely to require planning permission than rear extensions, particularly where they:
Extend close to the boundary
Alter the appearance of the side elevation
Reduce gaps between neighbouring properties
In some cases, limited side extensions may fall under permitted development, but this depends on width, height, and location.
All side extensions must comply with Building Regulations, covering:
Foundations and load-bearing walls
Structural steel and roof construction
Fire separation and escape routes
Insulation, ventilation, and damp protection
We ensure inspections are booked and approvals are obtained at every stage.
Local & Trusted Builders
Serving Harrow & surrounding areas
Proven experience delivering side extensions on Harrow properties
Strong understanding of boundary and neighbour constraints
Structural alteration and steel installation expertise
Clear build sequencing and site management
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 Side Extension
Trusted Builders in Harrow
Side extension specialists
We understand the structural and planning challenges unique to side extensions.
Boundary-aware construction
Careful management of foundations, walls, and access near boundaries.
Local knowledge
Experience working within Harrow’s planning and inspection processes.
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 extension projects in Harrow
How Much Does a Side Extension Cost ?
Side extensions in Harrow typically range from £2,200 – £3,200 per m², depending on layout and complexity.
Key cost factors include:
Width and length of the extension
Structural steel and wall removals
Drainage diversions and services
Roofing design and insulation levels
Internal finishes and fittings
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 house 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 side extensions need planning permission?
In most cases, yes. Side extensions often require planning approval due to boundary and visual impact considerations.
How long does a side 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 Side Extension Quote
Leave your details and we’ll get back to you to arrange a free site visit.
Our Service Areas
We build side extensions across Harrow and 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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