Builders in Swansea: the local rules
Swansea was Pelican Flat until 1887, when it took its present name, and it stands at the entrance to Lake Macquarie from the sea. Nearly all of Swansea sits in the Coastal Environment Area mapping, with large stretches of Coastal Use Area and coastal wetlands besides. The Swansea Hotel is its one heritage listing. A quarter of the suburb, in the south-west, lies inside the Swansea North Entrance subsidence district, and that corner also holds most of the bush fire mapping.
Two floors that don't line up
Extending a house usually means matching the old floor, so you walk from one room to the next without a step. At the lake entrance that isn't always possible. Council's waterway flooding policy sets a flood planning level for habitable floors, and an older Swansea house can sit some way under it. Where the new rooms have to meet that level, the addition ends up higher than the house it joins, and the difference is designed in from the start: a landing, two or three steps, or a change in ceiling height that makes the step feel intended.
The same policy points to flood resilient housing guidelines in council's development control plan, and under those a lower floor can sometimes be accepted. Which route suits your lot is a question for council's flood information, not a guess, so we read it before the drawings start.
When the Housing Code still works
A certifier can sometimes approve an extension under the state's Housing Code on a flood control lot, but only on the part of the land certified by council or a hydraulic engineer as outside the floodway, the flow paths and the high hazard areas. The addition must then meet extra standards: floor levels, flood-compatible materials, structural resistance, a way to take refuge and get out, and no worse flooding for anyone else. Acid sulfate land mapped Class 1 or 2, and Swansea has both, sits outside the code altogether. Where any of that rules the code out, council decides the addition through a development application.
The south-west corner
The quarter of Swansea inside the Swansea North Entrance district is mostly Guideline 8. That guideline puts no limits on the design, but it doesn't remove the approval step. Where the plan complies, council or a certifier may approve it and the agency never sees it. The Guideline 1 parcels there carry pothole risk, so footings are prescriptive or engineered and an officer inspects the steel before the pour. The bush fire mapping gathers in the same corner, so a lot there can need a bushfire assessment as well as a subsidence approval.
The structure, the price ranges and the order of work are on our extensions page. For the ocean side, where salt matters more than lake levels, see Caves Beach, and for the rest of the council area, start from Lake Macquarie.