Can I rent out a garden annex?

This depends on your planning permission conditions. Some approvals restrict use to 'ancillary' accommodation for family only, while others permit independent letting. We recommend discussing your intentions with your installer at the feasibility stage.

How much does a garden annex cost?

Garden annexes typically start from £65,000 and range to £120,000+ depending on size, specification, and finishing level. While this is more than a standard garden room, it's significantly less than a traditional extension or buying additional property.

Can I rent out a garden annex?

This depends on your planning permission conditions. Some approvals restrict use to 'ancillary' accommodation for family only, while others permit independent letting. We recommend discussing your intentions with your installer at the feasibility stage.

How much does a garden annex cost?

Garden annexes typically start from £65,000 and range to £120,000+ depending on size, specification, and finishing level. While this is more than a standard garden room, it's significantly less than a traditional extension or buying additional property.

Harrow · Middlesex

Garden Annexe in Harrow

Serving the London Borough of Harrow planning area · Harrow-on-the-Hill (Metropolitan line)

Self-contained living spaces perfect for guests, family, or rental income. Built to our 2026 Part L standard — adding £30,000–£75,000 to your Harrow property. From £65,000.

0.15 W/m²K

U-value

£30,000–£75,000

Value uplift

25–40 days

Build time

£103

LDC fee

Trusted by homeowners in Harrow

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Matched to Harrow installers who know London Borough of Harrow planning requirements.

Garden Annexe in Harrow, Middlesex

Harrow is a major Middlesex suburb anchored by the iconic hilltop school and a town centre that serves a wide catchment across northwest London. Its residential streets range from Victorian terraces near the station to spacious Edwardian semis and 1930s detached houses on the upper slopes — a varied stock that produces equally varied garden room opportunities. Harrow's mix of property types means nearly every garden size and layout is represented in our local project portfolio. Particularly in the Harrow Weald and Hatch End areas, generous plot sizes support larger bespoke builds. Strong professional household demographics sustain robust demand for dedicated home workspaces.

Why Harrow Homeowners Choose This Build

Keep family close while maintaining independence and privacy

Cost-effective alternative to care homes or house extensions

Increase your property value significantly

Faster construction compared to traditional building extensions

Potential rental income stream (subject to planning)

2026 Technical Specification

Wall construction150mm SIPs panels

U-value (wall)0.15 W/m²K

GlazingA-rated argon-filled

Acoustic reduction40dB+ standard

Data infrastructureCAT6A (10Gbps ready)

ElectricsPart P compliant

FoundationsGround screws (no concrete)

Build time25–40 days

FSC-certified timber · Ground screw foundations · Just One Tree partner

Planning in Harrow — London Borough of Harrow

Harrow-on-the-Hill Conservation Area covers the historic school environs and requires particular sensitivity for any visible outbuilding. The wider borough operates standard Permitted Development rules. The Harrow Council planning portal is straightforward for LDC applications — the £103 fee applies borough-wide.

£103

LDC fee

2.5m

Max height (boundary)

50%

Max garden coverage

London Borough of Harrow Portal Full PD Guide 2026

How We Work in Harrow

Feasibility Assessment

Check planning viability, site suitability, and building control requirements for habitable space.

Planning Application

Full management of the planning permission process, including design and submit documentation.

Building Control

Ensuring all regulations for habitable space are met, including fire safety and accessibility.

Complete Construction

Full build including all utilities, plumbing, electrics, and interior finishes.

See Completed Projects Near Harrow

Real builds with specs, materials, and planning routes documented.

View Portfolio

Garden Annexe FAQs — Harrow

Yes. Garden annexes intended for sleeping or living accommodation almost always require planning permission. Our partner installers manage the full application process on your behalf and can advise on the likelihood of approval in your specific borough.

“The team connected me with a fantastic installer who built my garden office in under 10 days. It's warm, quiet, and I love working from it every day.”

Sarah J.

Wimbledon, SW London · Garden Office

“Quick, professional, and totally transparent. I compared three quotes and picked the best one. My music studio is perfectly soundproofed.”

David M.

Highgate, North London · Music Studio