Permitted Development Extensions in Harrow

We provide clear, professional guidance on permitted development extensions in Harrow and surrounding areas. Whether you’re planning a rear, side, or two-storey extension, understanding local planning constraints and national permitted development limits is essential before work begins.

Common Permitted Development Issues in Harrow

• Overlooking concerns from upper floor windows
• Materials not matching existing dwelling
• Rear extension exceeds permitted projection limits Harrow
• Incorrect measurement from original dwelling
• Extension covering more than 50% of garden area
• Extension built beyond original rear wall line

Property Types We Advise On in Harrow

• Townhouses
• Properties with outbuildings
• Properties within conservation areas
• Homes subject to Article 4 Directions
• New build developments

Frequently Asked Questions

What is the maximum rear projection allowed?

Detached houses may extend up to four metres under standard rules, or eight metres with prior approval. Smaller limits apply to other house types.

Are there restrictions on side-facing windows?

Yes. Upper-floor side-facing windows typically must be obscure-glazed and non-opening below a certain height.

Can I remove a chimney without permission?

External alterations may require permission depending on property type and location.

Can I convert my loft and add a dormer?

Dormer loft conversions are often permitted development within volume limits.

What measurements are used for height?

Height is typically measured from the highest ground level adjacent to the building.

Does my extension need to match existing materials?

While not always mandatory under permitted development, matching materials is often recommended for visual consistency.

If you're planning an extension in Harrow and want to confirm whether it qualifies under permitted development rules, request a free assessment today and get clarity before you build.