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Sareth Build Journal

Plain-English guides to extending, renovating and self-building a UK home

Latest guides

Do You Need Planning Permission for an Extension? Permitted Development Limits Explained Planning & Permissions Do You Need Planning Permission for an Extension? Permitted Development Limits Explained Do I need planning permission for an extension? Often no, thanks to permitted development. Here are the exact UK size limits, rules and exceptions. 10 min read How to Serve a Party Wall Notice: Step-by-Step Template and Timeline Planning & Permissions How to Serve a Party Wall Notice: Step-by-Step Template and Timeline How to serve a party wall notice in the UK: the steps, a free template, exact notice periods and the timeline from service to award. 11 min read Planning Permission Refused: Your Options for Appeal and Resubmission Planning & Permissions Planning Permission Refused: Your Options for Appeal and Resubmission Planning permission refused? What to do next: read the refusal reasons, fix and resubmit a revised scheme, or appeal to the Planning Inspectorate. 10 min read Building Regulations vs Planning Permission: What's the Difference and When You Need Each Building & Regulations Building Regulations vs Planning Permission: What's the Difference and When You Need Each Building regulations vs planning permission explained: what each covers, when you need one, both or neither, and how to apply in the UK. 10 min read How to Get Building Control Sign-Off for an Extension (Full Plans vs Building Notice) Building & Regulations How to Get Building Control Sign-Off for an Extension (Full Plans vs Building Notice) Get building control sign off for your extension: full plans vs building notice, inspection stages, and how to get the completion certificate. 8 min read How Much Does a Single-Storey Extension Cost in 2026? Real UK Prices per m2 Costs & Budgeting How Much Does a Single-Storey Extension Cost in 2026? Real UK Prices per m2 Single storey extension cost in 2026, explained per m2: what drives the price, what is included, and the fees most quotes leave out. 9 min read Single-Storey vs Two-Storey Extension: Cost, Value and Which to Choose Extensions & Conversions Single-Storey vs Two-Storey Extension: Cost, Value and Which to Choose Single storey vs two storey extension compared on cost, value, planning and disruption, so you can pick the right one for your UK home. 9 min read The Complete UK House Extension Guide: Planning, Regs, Costs and Timeline Extensions & Conversions The Complete UK House Extension Guide: Planning, Regs, Costs and Timeline A practical house extension guide UK homeowners can actually use: planning permission, building regs, party wall, real cost ranges and a realistic timeline. 11 min read Extension Cost Calculator Tools Extension Cost Calculator Free extension cost calculator UK: estimate single-storey, two-storey, side-return and wraparound build costs by floor area, spec and region. Brick & Mortar Calculator Tools Brick & Mortar Calculator Free brick calculator for the UK: work out bricks, blocks, mortar bags and an indicative material cost for any wall from its size and skin type. Party Wall Notice Checker Tools Party Wall Notice Checker Do I need a party wall notice? Answer a few questions about your works and get the notice type, notice period and a starter notice to adapt.

Plain-English guides to extending, renovating and self-building a UK home. Sareth Build Journal is an independent UK resource covering UK home extensions, renovations and self-build: planning permission, building regulations, party wall, and project costs. We lead with practical how-to and troubleshooting guidance, back it with calculators you can actually use, and keep everything researched from primary sources.

Browse by section: Planning, Building Regs, Costs, Projects.