ePrivacy and GPDR Cookie Consent by Cookie Consent Five ways to save money when building a 'granny flat'

Five ways to save money when building a 'granny flat'

5 min read
Oct '25 • by Heather

Quick summary

To save money building a granny flat, convert existing structures like a garage, which can cost around £10,000 to £30,000 for 10-30 sqm, avoiding new foundations. Planning changes are easier if used for recreation, and loft or rear extensions can be alternatives under permitted rights. Consulting a specialist broker can also help find affordable finance options.

Did you know that nearly a third of UK homes are now multi-generational? It’s no surprise then that with this new housing trend, many homeowners are looking to add an annexe - or ‘granny flat’ - to their property.

Now don’t let the name fool you, a granny flat can benefit a number of people in your household, not just the older generation. In fact, the rise in multi-generational living has actually been driven by adult children returning to the nest. It’s this flexibility which makes annexes such a desirable addition.

If you’re considering adding an annexe to your home, you might have wondered about cost-effective ways of going about this. Like most home extensions, with a bit of expert knowledge, you’ll find there are plenty of ways to save yourself some pennies.

Here are five our favourites…

Use an existing structure / outbuilding

One of the easiest ways to cut down costs is to avoid building from scratch. You can do this by converting existing structures, such as a detached garage. This allows you to skip the cost of expensive construction elements, like the digging of new foundations, and focus solely on making the space habitable.

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