Are There Any Additional Costs When Building A Granny Annexe?

Multi-generational homes have become increasingly popular in recent years – either through adult children staying at home for longer or older relatives needing a bit of extra care.

One of the most popular solutions for such families is a prefabricated granny annexe. It can also be one of the most cost-effective options when you choose the right provider or builder.

Here are some average project costs and an explanation of any additional costs you may run into when building your granny annexe.

What Is The Cost Of Building A Granny Annexe?

If you set out to build your annexe, using separate contractors, there are many different costs to factor in, which may include; an architect, checking you are compliant with Building Regulations, planning permission services, and then the materials and labour required to build.

The beauty of prefabricated annexes, especially when you use a turnkey service like ours, is many of these costs are included in one overall package. This can save you money, and of course time and stress.

Prices for prefabricated annexes will also vary between providers but you can expect to pay upwards of £40,000.

Our high-quality annexes start at just £55,250 and go up to £105,250 for our largest two-bed model.

Will There be Any Additional Granny Annexe Costs?

As mentioned, the beauty of using an annexe builder is all your granny annexe costs will usually be wrapped up in on package meaning you can budget effectively and there won’t be any surprises.

Our turnkey service includes building plans, a site survey, planning permission service, and installation. Connection to utilities such as electricity and water are also included.  

This means once we have agreed what you want and hand over your plans and a quote, the price you see is the total cost for everything.

There are significant advantages to building your annexe this way; it’s often more cost-effective than sourcing separate contractors for each portion of your project, plus the process is more efficient and stress-free. Once you have signed your contract, you simply sit back and wait for your finished annexe.

Some families appreciate this hassle-free approach, especially when the need for an annexe is urgent. For example, if an older family member has become poorly and accommodation is needed sooner rather than later.

There are a few circumstances where you may incur additional costs with one of our packages, but most of them are voluntary.

For example, our annexes come with a standard specification, but you can upgrade any element of the design depending on your needs and budget. Step-in showers can be upgraded to wet rooms, a pitched rather than a flat roof can be added, and we can customise details such as cupboard doors and flooring. This will all be thoroughly discussed with you before we finalise your quote.

Groundworks are included in your package but there are some circumstances where additional works may be needed, and these can cost extra. Additional groundworks are sometimes required for a utility connection (water, for example) when your annexe is situated further away from your main property than is standard. This isn’t common in your average back garden though and would be picked up during our site survey.

Non-Build Costs To Bear In Mind

In addition to annexe building costs, there is some ongoing cost to bear in mind that are worth mentioning here.

Granny annexes are subject to separate council tax bills – if the annexe is used by the main house owner or a family member, this fee is reduced by 50%. However, the bill can be completely written off if your family member is classed as a ‘dependant’ (example include someone over the age of 65 or a family member with a substantial/permanent disability)

Annexe maintenance costs are minimal as our annexes are designed to be ‘weatherproof’ and last a long time, but you will need to factor in running costs for your annexe. This includes electricity, water, and internet/telephone bills. Most families have one bill for these utilities and then split accordingly but it is something you should discuss as a family before proceeding with your project.

Family Annexe

We hope this rundown of the basic prices and any additional costs has given you a better idea on the overall cost of building a granny annexe.

If you would like to ask us any questions about our annexes or prices, please give one of our friendly advisors a call on 0330 1332 668 or get in touch here.