Single & Double Storey Extension Builders in Harrow
We design and build single and double storey house extensions for homeowners in Harrow who need more space and long-term flexibility. Whether extending at ground level or adding an extra floor, our extensions are planned for structural safety, compliance, and practical use.
Trusted by local homeowners for well-constructed single and double storey extensions in Harrow.
Service Overview
Single and double storey extensions increase your home’s floor area either at ground level, across two floors, or both. The right approach depends on plot size, planning constraints, and how you want to use the space.
Single and double storey extensions are suitable for:
Terraced houses – often rear or loft-aligned double storey layouts
Semi-detached homes – rear, side, or wraparound double storey extensions
Detached properties – larger extensions with flexible layouts
Common uses for side extensions include:
Ground-floor kitchens and living areas
Additional bedrooms or bathrooms upstairs
Home offices or guest rooms
Reconfigured layouts to improve flow and storage
Double storey extensions are often chosen where garden space is limited but additional rooms are required.
Our Single & Double Storey Extension Process
Site Visit & Feasibility
We assess foundations, existing load paths, roof structure, and ground conditions to confirm whether a single or double storey extension is viable.
Design coordination & approvals
Architectural drawings and structural calculations are reviewed to ensure the extension can be built safely and complies with planning and building regulations.
Construction & inspections
Work is phased carefully, particularly for double storey extensions, with inspections at foundations, steelwork, floor structures, and insulation stages.
Completion & sign-off
All finishes are completed, building control approval is obtained, and the extension is handed over fully compliant.
Planning Permission & Building Regulations
Single storey extensions may fall under permitted development, depending on size, height, and location.
Double storey extensions usually require planning permission, with key considerations including:
Distance from boundaries
Impact on neighbours’ light and privacy
Overall height and roof design
All single and double storey extensions must comply with Building Regulations, covering:
Structural safety and load-bearing elements
Fire protection and escape routes
Thermal efficiency and sound insulation
Drainage, ventilation, and damp proofing
We ensure inspections are booked and approvals are obtained at every stage.
Local & Trusted Builders
Serving Harrow & surrounding areas
Proven experience with single and double storey builds
Strong understanding of structural sequencing
Expertise in steelwork and floor construction
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 Choose Us for Your Single & Double Storey Extension
Trusted Builders in Harrow
Structural expertise
We understand how to extend safely across one or two floors.
Planning-aware builds
Layouts are delivered in line with approved drawings and conditions.
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 Single and Double Storey Extension Cost ?
Typical costs in Harrow are:
Single storey extensions: £2,000 – £3,000 per m²
Double storey extensions: £2,200 – £3,200 per m²
Costs are influenced by:
Number of floors and structural complexity
Foundation depth and ground conditions
Steelwork and floor construction
Roofing and insulation requirements
Internal finishes and fittings
All pricing is project-specific and based on a detailed assessment.
NEED MORE INFORMATION?
Frequently Asked Questions
Answers to some of the most common questions we’re asked about Single and Double Storey extension .
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 single and double storey extensions need planning permission?
Single storey extensions may not, but double storey extensions usually require planning permission.
How long does a single or double storey extension take?
Single storey extensions typically take 10–14 weeks, while double storey extensions take 14–22 weeks, depending on complexity.
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 Single and Double Storey Extension Quote
Leave your details and we’ll get back to you to arrange a free site visit.
Our Service Areas
We build single and double storey 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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