Guides
Rear extension guides
Straight answers on depth limits, approvals, costs and building, written for homeowners and checked against official guidance.
How far can you extend at the back without planning permission?
Rear extension permitted development limits in England, Wales, Scotland and Northern Ireland, explained with depths, heights and the exceptions.
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The larger home extension scheme: 6 and 8 metre rear extensions in England
How England's prior approval route for 6 m and 8 m single-storey rear extensions works: eligibility, neighbour consultation, the 42-day decision and fees.
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Planning permission for a rear extension: when you need it and how to get it
When a rear extension needs a householder planning application, what the council looks at, what it costs and how long it takes.
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Building Regulations for rear extensions: what gets checked and when
What Building Regulations approval covers for a rear extension, full plans versus building notice, inspections, energy rules and the completion certificate.
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The Party Wall Act and rear extensions
When the Party Wall etc. Act 1996 applies to a rear extension in England and Wales, notice periods, surveyors and costs, and what happens in Scotland and Northern Ireland.
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Single-storey or two-storey rear extension: which should you build?
An honest comparison of single-storey and two-storey rear extensions: cost per square metre, planning, disruption and value.
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Flat roof or pitched roof for a rear extension?
How flat and pitched roofs compare on a rear extension: appearance, cost, light, lifespan and the planning height limits.
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Bifold or sliding doors for a rear extension?
Bifold versus sliding doors for a rear extension: sightlines, opening width, thresholds, security and cost.
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Side return or rear extension for a Victorian terrace?
How a side return infill compares with a rear extension or a wraparound on a period terrace: space, light, cost and planning.
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How long does a rear extension take?
A realistic timeline for a rear extension from first visit to completion: design, approvals, party walls, the build stages and sign-off.
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Does a rear extension add value to your house?
What the evidence says about how much value a rear extension adds, and how to judge it for your own street.
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How much glass can a rear extension have? The 25% rule explained
The 25% glazing guidance for extensions in England, how rooflights and doors count, and how heavily glazed rear extensions comply.
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Living at home during a rear extension build
How to stay in your house while a rear extension is built: the temporary kitchen, dust, noise, security and the knock-through week.
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Questions people ask
Are these guides legal advice?
No. They are general guidance checked against official sources; we confirm the rules for your house at the survey.
Do the rules differ across the UK?
Yes. England, Wales, Scotland and Northern Ireland each set their own permitted development and building rules.