Consider an extra tenant or two
Investment property owners wishing to boost their rental income can sometimes accomplish this by adding an extra bedroom.
The ability to add an extra living space - predominantly a bedroom, though having its own bathroom is a bonus - depends on the structure and layout of the existing rental property, and the block of land it sits on.
Generally speaking, the more you can offer an additional tenant - bedroom plus bathroom plus kitchenette plus lounge/dining, for example - the greater the increase in your income stream from that property might be.
Might any of the following be options?
Consider moving non-structural internal walls to make better overall use of the internal space
Consider turning the existing garage into self-contained living space. This could be a good option if the tenants are unlikely to need their own vehicles because of proximity to public transport.
Consider an extension to the existing property.
Consider building a granny flat.
Consider raising the house and building in the lower level.
Consider extending or raising the house and reorganising the original layout to create genuine shared accommodation.
All of the above require bringing in the experts – including building designers, builders, electricians and other trades – and meeting council, and any other, regulations.
If your investment property is well constructed, has good proximity to infrastructure and transport, and any changes you make will attract tenants and not detract from future capital gain, creating that additional rental stream might make more sense than simple wanting to put the rent up and up.