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Granny Flats and Extensions in Rouse Hill: Why Adding Space Now Adds Serious Value

Adding a granny flat or extension in Rouse Hill can boost your property value and rental income. Here's what you need to know about rules, costs, and timing.

TL;DR If your Rouse Hill property has a backyard you are not fully using, a granny flat or rear extension could be the best investment you make this year. Granny flats up to 60 square metres can be approved in as little as 10 to 20 days via complying development on lots of 450 square metres or more. With the new Rouse Hill Hospital creating hundreds of permanent healthcare jobs, rental demand in the area is set to increase. The 2026 tax changes preserve negative gearing for new builds — including granny flats — making them one of the most tax-efficient ways to generate rental income. Construction costs are rising at 4 per cent a year. Build now, not later. Introduction Rouse Hill homeowners are sitting on more value than many realise — not in the house itself, but in the unused space aroun…