House Extension Builders in Harrow
We design and build house extensions for homeowners in Harrow who need more space and a better layout without moving. From single storey extensions to larger structural builds, our work is carefully planned, properly managed, and built to last.
Trusted by local homeowners for compliant, well-built house extensions across Harrow and North West London.
Service Overview
A house extension increases the internal floor space of your home by building outward, upward, or both. Extensions allow you to adapt your property to changing needs while retaining the character of the existing building.
Homeowners choose extensions to:
Create larger kitchens and living spaces
Add bedrooms or bathrooms
Improve layout and flow
Increase property value
Extensions can be built to the rear, side, or over multiple storeys, depending on the property type and planning constraints.
Types of House Extensions
Homes across Harrow vary significantly in layout, access, and permitted development rights. We design each house extension around how your property is built, how you live in it, and how much space you need to gain — not a one-size-fits-all solution.
Rear extensions are the most popular option for Harrow homes, particularly terraced and semi-detached properties. They are ideal for homeowners looking to extend kitchen and dining areas or create open-plan living spaces without altering the front of the property.
Rear extensions can often be built under permitted development, depending on depth and height limits, and are well suited to properties with reasonable garden space.
Side extensions are a versatile option for increasing space by extending into unused side areas, replacing garages, or infilling between existing structures. They are well suited to improving ground floor layouts without significantly reducing garden space.
Planning requirements depend on size and boundary distances, which we assess during your site visit.
Wrap-around extensions combine rear and side extensions to maximise ground floor space. These are suitable for homeowners looking for a substantial layout change and are often chosen when creating large kitchen-living areas.
Due to their size, wrap-around extensions usually require planning permission, which we can manage as part of the project.
Single-storey extensions are ideal for expanding ground floor living areas, while double-storey extensions allow additional bedrooms, bathrooms, or home offices to be added above.
Double-storey extensions require careful planning and structural design, particularly where neighbouring properties are close, which is common across Harrow.
Our House Extension Process
Site Visit & Feasibility
We assess your property layout, access, and ground conditions, and advise on the most suitable extension options based on your goals and budget.
Planning & Design Coordination
Where required, we coordinate drawings, planning submissions, and structural calculations to ensure your extension complies with local authority and building regulations.
Managed Build Stages
Your extension is built in clearly defined stages, with inspections arranged at the appropriate points and regular progress updates throughout.
Completion & Handover
We complete all finishing works, carry out final checks, and ensure building control sign-off before handover.
Planning Permission & Building Regulations
Some house extensions fall under permitted development, depending on size, height, and location.
Planning permission is required when:
Extensions exceed permitted development limits
Building near boundaries or over multiple storeys
Properties are in conservation areas or are listed
All extensions must comply with Building Regulations, including:
Structural safety and foundations
Fire protection and escape routes
Thermal insulation and ventilation
Drainage and damp protection
We manage inspections and compliance throughout the project.
Local & Trusted Builders
Serving Harrow & surrounding areas
Proven experience delivering house extensions in Harrow
Strong understanding of structural alterations
Expertise in steel installation and load-bearing works
Careful management of occupied homes
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 Homeowners Choose Us
Trusted Builders in Harrow
Clear Build Stages
Structured extension builds with defined stages, timelines, and inspections.
Designed Around Your Home
Structured extension builds with defined stages, timelines, and inspections.
Fully Compliant Builds
All work carried out to current building regulations and inspected where required.
Transparent Pricing
Clear quotations following a site visit, with no hidden costs.
Our Projects
We take pride in delivering high-quality building projects across Harrow and surrounding areas.
Recent house extension projects in Harrow
How Much Does a House Extension Cost ?
The cost of a house extension in Harrow depends on size, specification, access, and structural requirements. Property type and ground conditions can also influence pricing.
As a general guide:
Rear extensions: £1,800 – £2,500 per m²
Side extensions: £2,000 – £2,700 per m²
Wrap-around extensions: £2,200 – £3,000 per m²
Costs are affected by:
Extension size and number of storeys
Structural steel and foundation requirements
Drainage alterations
Roofing design and glazing
Internal finishes and fittings
All quotes are project-specific and based on a site assessment.
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.
How long does a typical house extension take?
This depends on the size and complexity of the extension, but most single-storey extensions take 8–12 weeks once work begins. We’ll give you a clear timeline before starting and keep you updated at every stage.
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.
What types of house extensions do you build?
We build a wide range of extensions, including:
Rear extensions
Side extensions
Wrap-around extensions
Single storey extensions
Double storey extensions
Kitchen extensions
We’ll advise on what works best for your property and budget.
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?
In many cases, rear extensions in Harrow can be built under permitted development, meaning planning permission may not be required. This depends on factors such as the size of the extension, the height, proximity to boundaries, and whether the property has existing extensions.
How long does a single-storey extension take?
A typical single-storey house extension takes 10–14 weeks to build, depending on size, design, access, 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 Extension Quote
Leave your details and we’ll get back to you to arrange a free site visit.
Our Service Areas
We build house 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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