Granny over Double Garage Brick Veneer: Build Cost

Hi OZBs, friend is building a granny flat over double garage 120 sqm (all inclusive) brick veneer on a flat piece of land

60sqm garage and 60 sqm granny flat , metal stairs It is a basic build for granny.
Garage is with basic motorised garage doors. No bells and whistles.
Granny flat is 2 bed & 1 bath with laundry attached in bath plus kitchen. BASIX inclusions
electric meter, water meter , rain water tank installation included
paper work and CDC approval included
How much do you think would plan , paper work including plans to key handover cost ?

We are not owner builders asking for input to help a friend

Thank You for your time.

Poll Options expired

  • 10
  • 1
    211 - 230K
  • 3
    231 - 250K
  • 9
    251K - 280K


  • Depends on if you're in the middle of the desert or closer to a capital city.

  • Location?

  • we are building a granny over double garage 120 sqm

    This doesn't sound legal.

  • please measure again, most double garages are closer to ~6m x ~6m = 36sqm.
    further, please confirm your take on 'brick veneer' - is that just a single course of bricks as both interior/external walls, or is there something additional on the inside.
    too many variables. photos may help.

  • +13 votes

    Member since 7 hours. Welcome to OzB free consulting service.
    It is a pretty poorly structured request, insufficient and inaccurate information. So, is you are not an owner builder, then are you the builder, or asking for a friend?
    I would suggest first do some more research then make another post. Happy to help, just don’t look to take advantage of anything free.

  • +10 votes

    we are building a granny over double garage

    Is granny ok with that?

  • Need MS Paint diagram

  • You can build a whole house for less than 250k… or could pre-covid.

  • We are building a 4mx4m room on our 3rd story. It's basically adding 3 walls and a roof plus power (it was a store room).

    We are doing this across 4 residences.

    So far it's been $24k in "development" costs. I think it will top out at $45k including our project manager costs. The actual build to lock-up will be ~$250k. Carpet, paint, etc will add a little more.

    It works out at $75k per room.

    Why hasn't the granny flat got a kitchen?

    • Probably granny gets meals on wheels or Uber Eats. Well the location makes better sense now, closer to the cars to get meals.

  • Why hasn't the granny flat got a kitchen?

    My first thought on reading the post.

  • Ao you’re building the granny flat AND the garage?

  • be careful that garage has plenty of ventilation, and that living areas over and next to it have carbon monoxide alarms

    so many accidental deaths from cars left running by accident in garages that are attached to houses

  • Cost per sq meter will be between $2,000 to $2,200, as such price range for a 120m2 two level build will be between $240,000 to $264,000 inclusive off all designs, approvals, building costs, builder's profits and margins.

  • Where are you located? Have you had a preliminary chat with local council? Some councils are positive or neutral on granny flats, whilst others are anti and obstructionist.