Typical extension sizes
Understand what depths, heights, and layouts usually succeed in your area.
Typical Extension Sizes Insight helps you:
See commonly approved extension depths and heights near your property
Compare the sizes that succeeded versus those that failed
Make design decisions before paying for drawings
Understand local planning patterns, not just policy text
All based on real planning decisions from your area.
Know what tends to be approved in your local area
Before you design a home extension, one of the biggest questions is:
How big can it realistically be without risking refusal?
Planning policies give general size limits, but actual decisions often depend on local context — street patterns, distances to neighbours, rooflines, garden depth, and more.
Typical Extension Sizes Insight shows you what dimensions have actually been successful nearby, so you can plan with confidence.
What “Typical extension sizes” means for you
Instead of guessing or relying on broad policy language, this service looks at past planning decisions near your property and identifies:
Common depths and heights for successful extensions
Ranges that councils have consistently accepted
Outliers where applications were refused for being too large
Interpretations of the rules in real cases
That means you see what has worked locally, not just what the written rules allow in theory.
Why this matters to homeowners
Planning permission isn’t just about meeting a number on paper — it’s about:
How your extension affects neighbours’ light and privacy
Whether it fits into the pattern of development on your street
How council officers have interpreted similar proposals
Knowing typical extension sizes gives you:
Early design clarity
Rather than drafting plans that are likely too large, you have a realistic target before you spend on drawings or consultations.
Reduced risk of refusal
By designing within commonly accepted size ranges, you minimise reasons for refusal.
Better conversations with professionals
When you show your architect or designer the ranges that succeed locally, they can tailor your plans more effectively.
How it works
Tell us your address and project type
We start with where your property is and what kind of extension you’re considering (rear, side, loft, etc.).We analyse local planning history
We look at nearby planning applications with similar proposals and extract the dimensions that were approved and refused.You receive clear size guidance
A plain-English summary shows typical depths, heights, and other size metrics that have been approved near you.
No guesswork. No confusing regulations. Just evidence from real decisions you can apply to your planning.
How you can use this insight
Before you finalise drawings
Design within typical local size ranges to avoid unnecessary revisions.
To compare options
If your first idea is outside local norms, this insight helps you choose a more acceptable alternative.
To check feasibility
Understand early whether your goals align with what planning officers have approved nearby.
To validate your architect’s plan
Use this insight as a reality check before committing to architectural fees.
Who this is for
Homeowners planning extensions (rear, side, loft)
Anyone unsure how large their extension should be
People want context before detailed plans or applications
Homeowners seeking clarity before spending money
Real decisions. Relevant sizes. Informed planning.
Typical Extension Sizes Insight helps you design with confidence by showing what has worked near you, not what the rulebook merely suggests.