Designing a house extension often comes with more questions than answers—especially when it comes to detailing. Every existing building tells a different story, and navigating planning, sustainability, construction techniques, and client expectations can quickly become overwhelming. That’s exactly why House Extension Details: An Architectural Guide was created.

Authored by architect Aida Rodriguez Vega and architectural technologist Emma Walshaw, this new book is a comprehensive and practical resource aimed at professionals who are actively working on—or looking to specialise in—residential extension projects.

Designed with Practice in Mind

Rather than offering abstract theory or overly simplified summaries, this guide dives into the realities of designing and detailing extensions in the UK. It brings together over 200 construction details supported by contextual analysis, sustainability considerations, and a step-by-step breakdown of the extension process—from understanding the existing building to navigating building regulations.

A Wealth of Ready-to-Use Construction Details

At the heart of the book is an extensive library of over 200 construction details, carefully developed to reflect the realities of working on UK house extensions. These aren’t generic textbook diagrams—they’re clearly annotated, context-aware details that address the nuances professionals face on site and in practice.

Each example is presented in both 2D and 3D, with accompanying notes to explain the logic behind material choices, layering, junctions, and sequencing. You’ll find details for typical wall build-ups, roof intersections, thresholds, foundations, service layouts, and more—tailored to the kinds of situations that arise on real projects, not just idealised ones.

What You’ll Find Inside

• Guidance on assessing existing buildings and context
• Planning, permissions, and party wall processes explained clearly
• Sustainable design principles for extensions
• Design approaches for different extension types and massing
• Detailed design by element: foundations, walls, roofs, drainage, services, and more
• A full section dedicated to 200+ annotated 2D and 3D construction details
• Materials guidance, budget considerations, and building regulations summaries

The structure is intuitive and intended for dipping in and out—useful whether you’re deep in technical drawings or reviewing early design options with a client.

A Practical Companion for Everyday Practice

If you’re working solo, or as part of a small team, having reliable, well-researched resources at your fingertips can make a real difference. This book won’t make the decisions for you, but it will give you a solid foundation to build on—backed by research, tested experience, and architectural rigour.

If you’d like to take a closer look, you can preview the contents or learn more via the First In Architecture shop.