Excavate down into the ground to get additional head height for a Queenslander

We've been quoted (ballpark, over the phone with the lifting company looking at the property on google earth) with roughly $90k to disconnect services, lift and slide a few metres sideways and forward, slab underneath, reconnect services, build new steps front and back.

We have battens under the house now, so no loss of what already is there. With this house, you lose everything on the ground floor. So you pretty much have to rebuild it.

The same job we were quoted about $90k will (according to the draftsman who drew up the plan for the lift) cost about $300k to do the total job, build under to make it habitable.

You'd need to work out what this house would be worth if it was legal height, what it might cost to make it legal height, and what sort of rental or resale return you would get for the money spent to make it legal height. I'd be guessing it isn't worth doing.

You can still rent it out but have to call the downstairs rooms "store room". That won't stop a family from using those rooms for whatever they want to use them for.

If you call a local builder, you could get a ballpark figure and then find out from a local agent what it would be worth once done. That will tell you whether it is worth doing.