Buying a sloping block might sound scary. Foundations, drainage, retaining walls, yikes. But with the right builder? It’s an opportunity.

A builder’s price list only tells part of the story. An inclusions list covers the standard fixtures, fittings and finishes included in the base price, while anything outside that range is usually an upgrade. With custom selections, each item is specified and priced for your home before you sign. Always compare what is included, not just the headline price.

Prime cost items and provisional sums are allowances in a building contract for costs that cannot be finalised when you sign. A PC item covers products you will choose later, such as tapware or appliances. A provisional sum covers uncertain work, such as excavation. If the actual cost exceeds the allowance, you usually pay the difference plus the builder’s margin.

A spec home is built before a buyer is found, a project home uses a preset builder plan on your land, and a custom home is designed specifically for your block and lifestyle. Spec homes are usually quickest, while custom homes offer the most flexibility, especially for sloping, unusual or view-facing sites.

Building a 4 bedroom house in NSW in 2026 typically costs $2,000–$3,800 per m². A 250 m² mid-range home may cost around $600,000–$700,000 for construction alone, or roughly $735,000–$955,000 all-in once site works, approvals, connections, landscaping and contingency are included. Land is additional.

A home extension in NSW in 2026 typically costs $2,000–$3,800 per m² for a ground-floor addition and $2,400–$4,400 per m² for a second storey. A 45 m² mid-range ground-floor extension may cost around $108,000–$126,000 to build, or roughly $145,000–$195,000 all-in once site works, approvals, fees and contingency are included.

Getting building quotes for a duplex shouldn't feel like decoding a foreign language. Yet here you are, staring at three wildly different numbers, wondering why one builder quoted $850,000 while another came in at $1.2 million for what looks like the same project. 

I've seen too many Wollongong duplex projects stall because people didn't know how to request proper quotes. Let me save you months of frustration and potentially tens of thousands of dollars. 

Corner block duplexes aren't just about location- they're about opportunity. If you're a first-time homebuyer, long-term investor, or retiree looking to build smart in Wollongong, corner blocks offer advantages that standard lots simply can't match. 

Yes, it's possible to build a duplex on a narrow block, but with conditions. After 25 years of building duplexes across Wollongong and the South Coast, I've designed countless solutions for narrow blocks that looked impossible initially. 

Duplex investment in Wollongong has moved beyond being just an affordable entry point. It's become a genuinely smart strategy for investors, downsizers, and multigenerational families who understand property fundamentals. 

Building a house in NSW in 2026 typically costs $2,000–$3,800 per m² for construction alone. A 200 m² mid-range home may cost around $480,000–$560,000 to build, or roughly $655,000–$890,000 all-in once site works, approvals, connections, landscaping and contingency are included. Land is additional.

The cheapest way to build a house in NSW is usually a compact, single-storey design on a flat block with a simple footprint and basic to mid-range finishes. A 180 m² home built this way may cost around $525,000–$740,000 all-in before land. Steep sites, complex designs and premium finishes can push the same-size home above $1 million.

Planning to build a custom home? You’ve probably heard “It’ll take about a year.”

But what does that year actually look like?