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.

Northwood · Middlesex

Garden Annexe in Northwood

Serving the London Borough of Hillingdon planning area · Northwood (Metropolitan line)

Self-contained living spaces perfect for guests, family, or rental income. Built to our 2026 Part L standard — adding £40,000–£95,000 to your Northwood property. From £65,000.

0.15 W/m²K

U-value

£40,000–£95,000

Value uplift

25–40 days

Build time

£103

LDC fee

Trusted by homeowners in Northwood

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Matched to Northwood installers who know London Borough of Hillingdon planning requirements.

Garden Annexe in Northwood, Middlesex

Northwood is an affluent Middlesex suburb of large detached and substantial semi-detached homes, many set on generous plots with mature trees and established gardens. Its Metropolitan line connection to Baker Street and the City makes it a popular choice for professional families who want space and quiet without sacrificing London access. Northwood's property stock consistently features the largest gardens in the northwest Middlesex corridor — frequently 100 feet or more in depth. This creates genuine scope for architectural garden room builds with separate zones for work, fitness, and creative use. The premium household profile here sustains demand for the highest specification builds.

Why Northwood 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 Northwood — London Borough of Hillingdon

Northwood falls within Hillingdon's planning area. No significant conservation restrictions apply across most of Northwood's residential streets, though some tree preservation orders (TPOs) on mature garden specimens may affect foundation positioning. Your installer will identify any TPOs at the site survey.

£103

LDC fee

2.5m

Max height (boundary)

50%

Max garden coverage

London Borough of Hillingdon Portal Full PD Guide 2026

How We Work in Northwood

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 Northwood

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

View Portfolio

Garden Annexe FAQs — Northwood

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