buy with granny flat or build one?

i see a few properties selling with granny flat (dual living) for premium price 100k over median. they both rented separately so CF is quite good and they on same title, so rates are "normal". so last one was advertised for 500k with 520 a week rent combined. same houses sell for ~ 380-400k with ~ 400-420 a week rent.

is it worth buying the house with GF or better to build one yoursef (not a builder, so would need to hire obviously)

thoughts?

 

Just be mindful that construction costs have risen significantly so you need to factor this in.

Construction is Sydney right now isn't fun - not saying one way or another but just consider these when deciding options.