ePrivacy and GPDR Cookie Consent by Cookie Consent Resi | Research Hub

Research Hub

Browse real extensions, calculate costs and design your own extension, all in one place

Top extensions for you
Guides for your project
A side return or infill extension, featuring a glazed ceiling and sliding doors.
Costs And Financing

How much does a side return extension cost?

Published Feb '18 • Last updated Feb '26 • 7 min read →
A large kitchen diner with natural light coming from skylights and sliding glass doors.

Kitchen extensions: the ultimate guide for UK homeowners

Published Dec '21 • Last updated Oct '25 • 9 min read →
A woman uses her new country-style kitchen, made possible through permitted development rights and a rear extension.
Planning Permission

Do you need planning permission for a single storey extension?

Published Jan '22 • Last updated Oct '25 • 6 min read →
This rear extension project was financed under a remortgage and built in London.
Planning Permission

Can I add a rear extension under permitted development in the UK?

Published Aug '22 • Last updated Oct '25 • 8 min read →
Building an extension to your neighbours- boundary
Planning Permission

How close can you build your extension to your neighbours' boundary?

Published Jun '23 • Last updated Oct '25 • 3 min read →
A conservatory kitchen extension exterior shot, taken in London from a house extension project from 2019.
Planning Permission

House extension without planning permission: what are the rules?

Published Feb '22 • Last updated Oct '25 • 10 min read →
A single storey side extension with glass ceiling.
Costs And Financing

Single storey extension costs: what you need to know

Published Jan '22 • Last updated Oct '25 • 6 min read →
The grey flooring outside the home moves into the rich, warm material of the kitchen.
Costs And Financing

The cost of a rear extension in the UK and how to save some pennies

Published Aug '22 • Last updated Oct '25 • 8 min read →
A shovel goes into the soil of a property, ready to assess the foundations for a single storey extension.
Construction And Builders

What is the ideal depth of foundations for my single storey extension? 

Published Jan '22 • Last updated Oct '25 • 5 min read →
Most loved projects

Configure your own design

Browse examples, calculate costs and design your own extension with Resi Research Hub Get started
Budget friendly ideas
Dream big

Share your feedback

Would you recommend this tool to others?

Contact

+44 208 068 4811 [email protected]
Instagram
Youtube
TikTok
Houzz
LinkedIn
Facebook
X

Locations

Popular Locations

Design

Design & Planning

Connect

Building Contractors Structural engineers Building control approvers CCTV drainage surveyors Party wall surveyors

Finance

About Resi finance Find a loan

Portfolio

Kitchen Bedroom Bathroom Garden Facade Ground floor First floor Loft

Resources

Research hub Advice centre All advice articles FAQs House extensions: everything a homeowner needs to know The cost of a rear extension in the UK and how to save some pennies 5 things to know before doing a hip to gable loft conversion Loft Conversion Costs UK 2025: A Complete Guide to Budgeting Your Build All you need to know before starting your side return extension project

Free tools

Project cost calculator Permitted development quiz Home value estimator

Company

About us Careers Resi foundation Terms of use Privacy policy

Partners

Tradesperson sign up

Copyright © 2016-2026 Resi Design Ltd.

Resi Design Ltd. trading as 'Resi' | Company No: 10471125

We are proud to employ architects registered with the Architects Registration Board and were awarded the mark for The Mayor's Good Work Standard for fair pay & conditions, wellbeing, skills, progression, diversity and recruitment.