How Much Does A Granny Annexe Cost In 2026? Full UK Price Guide

A granny annexe can provide practical and comfortable living spaces for your elderly relatives, adult children, guests or anyone who needs a little more independence at home. However before starting a project it is important to understand the costs involved.

So, how much does a granny annexe cost in 2026? Across the UK, prices can vary considerably depending on the size, design, specification, groundworks and connections required. Current published prices suggest that compact annexes can start from around £52,000, while larger two bedroom designs can cost £155,000 or more before certain site costs are added.

What Is the Average Granny Annexe Cost in 2026?

The granny annexe cost 2026 depends largely on the size and level of finish you choose. A compact studio style annexes may cost around £52,000 to £70,000, while bedroom annexes can range from approximately £70,000 to £115,000. Larger two bedroom properties can reach £95,000 to £155,000 or more.

For example, current prices from The Granny Annexe Company include turnkey designs starting at £67,000 for a 22 square metre studio and around £88,350 for a 36 square metre design. Larger options are available at higher prices depending on size and specification.

Granny Annexe Prices UK: What Affects the Cost?

There is no single price for every project. Several factors can influence granny annexe prices UK homeowners see when requesting quotes.

Size and Layout

The larger the annexes, the more materials, labour and fittings are generally required. A simple studio with an open plan living and sleeping area will usually cost less than a property with separate bedrooms, a larger kitchen and additional bathroom facilities.

Kitchen and Bathroom

A fully fitted kitchen and bathroom add to the overall cost. The choice of appliances, worktops, your sanitaryware, storage and finishes can also affect your final budget.

Groundworks and FoundationsGroundworks and Foundations

The condition and accessibility of your home garden annexes can make a very significant difference. Some of your projects require additional excavation, foundations, drainage work or preparation before construction can begin. Industry pricing information suggests groundworks and mains connections can add around £15,000 to £20,000 where they are not already included in the quoted price.

Utilities and Connections

All your garden annexes will normally need electricity, water, drainage and heating. The distance between all the garden home annexes and existing household services can affect connection costs.

Specification and Finishes

Flooring, insulation, windows, doors, heating systems, kitchen fittings and interior finishes all contribute to the final price. Choosing a bespoke design or premium materials can increase the budget further.

What Does a Garden Annexe Cost in the UK?

The garden annexe cost UK homeowners pay can therefore range from a compact project of around £50,000 to considerably more than £150,000 for a large, highly specified property.

For example, current turnkey examples from The Granny Annexe Company range from £67,000 for a 22 square metre studio to more than £150,000 for some larger designs. Their listed prices include many features such as foundations, electrical installation, bathroom and kitchenette fitting, insulation, delivery and installation.

This garden home annexe highlights why it is important to check exactly what is included in a quote rather than comparing headline prices alone.

Planning and Other Costs to Consider

Planning requirements depend on the property, location, proposed use and design. Self contained garden annexes may require planning permission, while some projects may follow a different legal route. Building regulations can also apply because an annexe intended for living accommodation is different from a simple garden room.

Planning application fees can also vary depending on your type of application. From April 2026, national planning fee categories include fees for different types of householder and building applications.

It is worth checking the planning position before committing to all design or ordering a building.

Is a Granny Annexe Worth the Investment?

All granny annexes can provide additional accommodation without moving to a larger property. It may offer privacy for family members while keeping them close to the main household.

The key is to create a realistic budget from the beginning. Look beyond your basic building price and consider foundations, utility connections, planning, interior specifications and any preparation your garden may need.

For more information about available designs, pricing and turnkey annexe options, visit The Granny Annexe Company.

Final Thoughts

Understanding all the costs before starting your project can make the process much easier. In 2026, UK granny annexes can range from around £52,000 for smaller designs to £155,000 or more for your larger properties, with the final cost depending on size, specification and site requirements.

Always request your detailed quotation that clearly explains what is included in your home garden annexe project. Comparing complete project costs rather than starting prices can help you create a more accurate  budget for your new annexe.