Call Free: 0800 334 5774
Call Free: 0800 334 5774


What are the expected costs of building a Granny Annexe

Constructing an outdoor building in your home’s garden is often seen as a great investment and a sure way to create added value to your property. An annexe is often created for a very specific need, usually for an elderly relative, or increasingly, for a younger relative who might not yet be able to afford their own home. In both cases, it is a fantastic way to create an independent living solution that will be an asset to your property for years to come.

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All of the buildings that we construct are bespoke and designed especially for each of our customer’s needs. No two annexes are the same. Having said that we can still provide an example of what a typical annexe might cost based on some of the base models that we construct.

Our most compact annexe starts from £55,162.85 inc VAT. The Tiree is a one bedroom annexe with 24 m2 external area (6m x 4m). Comprising of a kitchen-diner and a studio bedroom with en suite. It provides all of the essentials for a comfortable home, while also being small enough to fit into most gardens, either lengthways of longways.


The Tiree, like all of our annexes, comes fully fitted out with a high-end kitchen, shower room and all internal fittings. We offer a complete turnkey service, from design to construction to handing you the keys.

Planning Permission

All of our annexes require planning permission as they are permanent structures designed to be lived in. While a few companies offer annexes built under the ‘Caravan Act’ this is not something we would recommend as if the planning authorities deem the building to not be ‘mobile’ then you might be asked to remove the building. We believe in constructing quality buildings with proper foundations that will last a lifetime.

A full planning service for an additional cost of  £1672.00 inc VAT can reduce many of the stresses of starting a new building project, with us taking care of all or the planning and building regulations you can be sure that your annexe’s planning is in the best hands. Often these initial stages can be some of the most stressful parts of a project, but our team of highly experienced professionals can take the burden out of the process.


Larger Annexes

If you require a bit more space, then an annexe with a separate en suite bedroom normally starts from £59,896.31 inc VAT. With 28 m2 external area, there is capacity for a separate bedroom, kitchen diner and living room. An even larger 2 bedroom annexe with 58 m2 external area might typically start from £100,356.50 inc VAT.


A larger annexe can provide even more space and versatility, it is possible for us to design and construct a 2 bedroom annexe, but it is important to be aware that planning permission might be more difficult to get unless you can provide evidence that 2 bedrooms are required for the purpose of the building.

2 bedroom annexes have a lot of space and can easily accommodate a separate kitchen, study or have an en suite and a bathroom. How you configure your annexe is up to you, we will build your annexe to your specifications and be able to guide you as to what layout and floorplan would work best for you.


A full break down of our prices can be found on our website, with sizes ranging from 24 m2 to 60 m2 external area.


Optional Extras

The size of your chosen annexe, building materials and optional extras, can all affect the price that we send in the quote. Some of the most popular optional extras that we offer are engineered Oak flooring, underfloor heating, ramps and rails and external elements such as decking and lighting. The price for a newly constructed annexe usually varies a little from the list price on our website as many customers would like to make small changes to the shape, size and layout. We have our own team of in-house designers who are able to take care of all the design elements of the project free of charge. After discussing with you your requirements and design ideas we get to work in producing the first drawings, we then send you your quote with a 3-D drawing of your bespoke annexe with a floor plan and a garden aspect plan to help you visualise where everything is going.

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Adding value to your home

It is generally accepted that building an annexe will increase the value of your home at least by the amount that you have spent on its construction. These days many people who are searching for a new home are looking for flexible accommodation, either to accommodate relatives, occasional guests or to use as a home office. An annexe will remain a versatile and useful addition to any home, adding value, space and functionality.

How much does an annexe cost to maintain?

We feel that you will be pleasantly surprised at how little an annexe costs to maintain once it is constructed. We only use the highest quality materials in the construction of our buildings that are built to last. The walls are constructed using structural, thermally insulated panels with either render of wood cladding. This provides excellent protection to the elements and only requires general maintenance in order to keep in lasting order for years to come. Being made from SIPs (Structurally Insulated Panels) means that the cost to heat our annexes is very low compared to a typical house. The excellent thermal performance means that the annexes we build are cheap to heat in the winter yet remain cool in the summer. Modern regulations and building techniques also mean that we only utilise the most modern electrics, with eco-friendly LED lights that cost less to replace in the long term.

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How does the cost of an annexe compare to a similarly sized bungalow?

Costing from between £60,000 – £110,000 for a typical annexe you can expect to make a huge saving compared to the cost of a traditional bungalow, small house or flat in most regional areas. When you build an annexe in most cases the land is already paid for, which can be the most expensive part of a new build project. Utilising your garden to build can be seen as a sure investment with any structure adding value and versatility to your property. With housing in short supply (especially bungalows) it makes increasing sense to build in your garden as the costs of housing is continuing to rise and becoming unaffordable in a lot of areas. When you add this to the practicality and care benefits of having elderly relatives close by then an annexe can make a lot of sense to many families.


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