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, consider converting existing structures like a garage or outbuilding, which can cost around £1,000 to £3,000 per sqm for essential updates, avoiding full new build costs. Planning ahead by building recreational spaces first can also spread costs over time, while using permitted development rights can help avoid planning fees.

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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