Granny flat prices advertised online often look simple. The real cost depends on your site and what is included. Here is what drives the price of a granny flat in Sydney.
Size and design
Under the NSW complying development rules, a secondary dwelling can be up to 60 square metres internally. Bigger is not always proportionally dearer, but more bedrooms, bathrooms and kitchen joinery add up. Simple rectangular designs cost less than complex roof forms and lots of corners.
Site costs (the usual surprise)
- Slope: cut, fill and retaining walls on sloping blocks.
- Access: narrow side passages mean smaller machines, pumps and more labour.
- Slab and footings: reactive clay or fill needs a stiffer slab or piers. See concrete slab cost.
- Trees and demolition of sheds or old structures.
Services connections
- Sewer: the distance and depth to the sewer, and sewer lines running through the site.
- Power: switchboard or supply upgrades for a second dwelling.
- Water and stormwater connections and drainage.
Approvals and compliance
CDC or DA fees, certifier costs, BASIX, engineering, surveys and any reports such as bushfire or flood. See granny flat requirements in NSW.
Kit home vs custom build
Kit granny flats can look cheaper, but site works, slab, connections, approvals and assembly are often extra. Compare like with like: ask what is included from the ground up to handover.
Finishes
Kitchens, bathrooms, flooring, windows, air conditioning and outdoor areas vary enormously in price.
Questions to ask every granny flat builder
- Is the slab, site cut and retaining included?
- Are sewer, power, water and stormwater connections included, and how far?
- Are approvals, certifier, BASIX and engineering included?
- What is excluded?
Granny flats in Sydney
We price granny flats from the ground up after a site visit, so you know the full cost. See our granny flat service or call 0415 840 500.
Frequently asked questions
How big can a granny flat be in NSW?
Under complying development, a secondary dwelling can be up to 60 square metres internally.
What are the hidden costs of a granny flat?
Usually site works on sloping blocks, slab upgrades, sewer and power connections, approvals and anything excluded from kit prices.
Is a kit granny flat cheaper?
Sometimes, but site works, slab, connections, approvals and assembly are often extra. Compare full scopes.
