We use essential cookies to run this site, and optional cookies only with your consent. Cookie policy AcceptReject Open 7 days · Hours vary by day · 25 years' experience Office: 01279 216 215 | Mobile: 07932 442502 Services Areas About Our Work Blog Reviews Contact 01279 216 215 Free Quote - Home - Blog - Extensions: When You Need Planning Permission and When You Don't Building # Extensions: When You Need Planning Permission and When You Don't Updated May 2026 8 min read By Jamie Pocock Most homeowners assume any extension needs planning permission. In reality, around 60% of the extensions we build go through Permitted Development — no full planning application needed, faster start, lower fees. Here's how to tell which route applies to your project, accurate for England in 2026. ## What Permitted Development actually allows Under the General Permitted Development Order, a semi-detached or detached house can extend without full planning permission within these limits: - Single-storey rear: up to 6m for semi/terrace, 8m for detached, max 4m height, max half the garden width - Side extension: single-storey only, max 4m high, max half the original house width - Two-storey rear: up to 3m projection, min 7m from rear boundary, matching roof pitch - Materials: must be similar appearance to the existing house ## What disqualifies you from PD Permitted Development is removed in: - Conservation areas (parts of Bishop's Stortford, Saffron Walden, Sawbridgeworth) - Areas of Outstanding Natural Beauty - Listed buildings (always need Listed Building Consent) - Properties where PD rights have been removed by an Article 4 direction - Any house created from a flat conversion or originally a maisonette ## The Larger Home Extension scheme (Prior Approval) Single-storey rear extensions between 4–6m (semi/terrace) or 4–8m (detached) need Prior Approval — a lighter-touch process than full planning. Council notifies neighbours; if no objections within 21 days, you're approved. Takes 6–8 weeks total. ## When you definitely need full planning - Two-storey extensions exceeding PD limits - Anything in a Conservation Area or AONB - Side extensions on a corner plot facing a highway - Any extension on a Listed Building (also needs LBC) - Building over the boundary or close to a public right of way Full planning takes 8–13 weeks in our local councils (East Herts, Uttlesford, Epping Forest) and costs £258 in application fees. ## Building Regulations apply either way Critically — even if you don't need planning, you still need Building Regulations approval. This covers structural, thermal, fire and ventilation compliance. As CRC-certified contractors we can self-certify most elements and coordinate the building inspector for you. ## What we handle for you On every extension project we manage: - Initial planning route assessment (free, on-site) - Architect introduction or working from your existing drawings - Planning or Prior Approval submission - Structural engineer coordination - Building Regulations submission and inspector liaison - Party Wall agreements where needed - Full build through to handover ## Realistic timeline 2026 From first conversation to keys-in-hand on a typical single-storey rear extension under PD: 4–6 months. Two-storey under full planning: 7–10 months. We give you a Gantt chart on day one so you can see exactly what's happening when. ExtensionsPlanning FAQs ## Frequently asked questions ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> How do I know if my house is in a Conservation Area? ### svg]:rotate-180 text-left font-bold text-base hover:no-underline py-5" data-radix-collection-item=""> Can you start work as soon as planning is approved? ## Thinking about an extension? Start with a free planning chat. We'll visit your home, tell you straight whether your project is PD, Prior Approval or full planning — and what realistic costs and timelines look like. See our extensions service 01279 216 215 More from the blog ## Keep reading Roofing ### Winter Roof Checklist: 12 Things Every Hertfordshire Homeowner Should Check Before December The 12 things that cause 90% of winter roof leaks in Hertfordshire — and how to spot them in 20 minutes from the ground. 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Open seven days. 01279 216 215 (office) 07932 442502 (mobile) info@jandco-contractorsltd.co.uk 1 Ugley Hall Cottages, Bishop's Stortford CM22 6JB Open 7 days a week - Sun 07:00–17:30 - Mon 07:00–17:00 - Tue 07:30–17:00 - Wed 07:00–17:30 - Thu 07:00–17:30 - Fri 06:00–18:00 - Sat 09:00–17:00 We accept VISAAMEX PayG Pay ### Roofing - All roofing services - Flat Roofing - Roof Repairs & Maintenance - Emergency Roof Repairs - Guttering, Fascias & Soffits - Chimney Repairs & Repointing ### Building & Construction - All building services - Building & Extensions - Loft Conversions - Renovations & Refurbishments - Brickwork & Masonry - Damp Proofing & Waterproofing - Plastering & Rendering - Patio & Driveway Installations - Fencing & Garden Walls - Property Maintenance ### Areas We Cover - Bishop's Stortford - Stansted Mountfitchet - Sawbridgeworth - Great Dunmow - Harlow - Saffron Walden - Epping - Ware - Hoddesdon - Broxbourne - Cheshunt - Welwyn Garden City - Stevenage ### Company - About J&Co - Our Recent Work - Blog - Customer Reviews - Contact Us © 2026 J&Co Builders Ltd · Trading as J&Co Contractors · All rights reserved. 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