Transparent pricing guides to help you plan and budget your project with confidence.
Planning a house extension, loft conversion or renovation in London? Our free cost guides give you real 2026 prices, typical project timelines, and honest guidance on what drives costs — so you can budget accurately before speaking to a builder.
Every guide is written by Alstruct, an active London construction company. The figures reflect what we actually quote and charge, not estimates pulled from national averages.
How much does a house extension cost in London? Detailed costs for single-storey, double-storey, side and wraparound extensions — with price per square metre, what's included, and what drives the cost up.
Read Guide →Dormer, Velux, hip-to-gable and mansard loft conversion costs in London. Understand which type suits your property, typical price ranges, planning requirements and how to get the best value.
Read Guide →The side return extension is one of the most popular transformations for Victorian terraces in London. This guide covers typical costs, design options, planning rules and how to maximise the space.
Read Guide →Do you need a party wall agreement? How much does a party wall surveyor cost in London? This guide explains when you need one, what the process involves, typical surveyor fees and how long it takes.
Read Guide →