Tarrawanna — Sloping Block Custom Home

The challenge — a steeply sloping Tarrawanna block that standard builders would struggle with

Tarrawanna sits in the northern Illawarra between the escarpment and the coast, in a band of established suburbs where the terrain drops significantly from the highway toward the sea. The blocks in this area are frequently sloping — sometimes steeply — and the combination of established streetscapes, neighbouring properties, and Wollongong City Council requirements means the approach to design and approvals needs to be considered carefully from the beginning.

This project came to Evolution Building Group from clients who had already been told by at least one other builder that the site was too difficult to work with without excessive earthworks and cost. The slope was significant, the access was constrained, and the standard response of cutting the site to a flat platform would have produced an outcome neither practical nor cost-effective for the block.

The clients wanted a custom home that felt spacious, took advantage of the views available from the elevated position, and worked with the natural gradient of the land rather than fighting it. They also needed a clear picture of what the project would cost before committing.

The approach — split-level design and site-responsive thinking

Starting with feasibility, not a floor plan

EBG's process on this project began with a $990 Design Your Happy Place session with Jaison Grassato. The session assessed the site conditions — the degree of slope, the access point, the retaining implications, and the likely structural approach options. A preliminary cost range was established that gave the clients a real picture of what the project would involve financially before any design work was commissioned.

That early clarity was what allowed the clients to make a confident decision to proceed. The $990 session identified that a split-level design using a pier-supported lower level stepping into a slab-on-ground upper level was the most cost-effective structural response for the specific gradient on this block — substantially reducing the earthworks and retaining cost compared to a cut-and-fill approach.

Split-level design — using the slope as an advantage

The final design steps the home across two primary levels that follow the natural grade of the land. The lower level contains the main bedroom suite and two additional bedrooms — taking advantage of the quieter, more private position at the lower end of the block. The upper level holds the open-plan kitchen, dining, and living areas, with a rear deck elevated above the lower garden that captures the available outlook across the Illawarra escarpment.

The result is a home that feels considerably larger than its footprint would suggest — the level change creates a natural separation between the living and sleeping zones that a single-level plan on a flat site would struggle to achieve without additional area and cost.

Retaining and earthworks — managed as part of the project

The split-level design significantly reduced the retaining wall requirement compared to a single-level cut-and-fill approach, but retaining was still required at the entry level and along one boundary. EBG scoped, priced, and constructed the retaining walls as part of the overall build scope. The retaining cost was included in the preliminary tender produced at the Design Your Happy Place stage, so there were no surprises when construction began.

DA approval pathway — navigating Wollongong City Council

The degree of earthworks, the split-level structure, and the site's position within an established streetscape meant this project required a Development Application through Wollongong City Council rather than a CDC. EBG managed the DA process from the preparation of the application through to determination. The approval was obtained without significant amendment to the design.

The outcome

• Split-level layout with natural separation between living and sleeping zones
• Elevated rear deck with escarpment and treetop outlook
• Earthworks cost substantially lower than a cut-and-fill single-level approach
• Retaining walls integrated into the design and built as part of the project scope
• DA approved through Wollongong City Council without design amendment
• Clients moved in with a complete picture of what every stage had cost

The result

This Tarrawanna project delivered what the clients needed from the beginning — a home that worked with the slope rather than fighting it, at a cost that had been clearly established before design was committed. The split-level layout created natural separation between the living and sleeping zones that a single-level home on a prepared platform could not have achieved on this block. The elevated rear living areas capture the available outlook across the northern Illawarra. The retaining, the earthworks, and the DA process were all managed by EBG as part of the integrated project scope — the clients moved in with a complete picture of what every stage had cost and no surprises along the way.

Frequently asked questions

Can I build a custom home on a sloping block in Tarrawanna?

Yes. Evolution Building Group has completed a custom home on a sloping block in Tarrawanna and works across the Illawarra on sloping and constrained sites of all types. The starting point is a $990 Design Your Happy Place session with Jaison Grassato — 0413 717 823 — which assesses your specific site and produces a preliminary cost range before any design commitment is made.

What is the best design approach for a steeply sloping Illawarra block?

On steeply sloping Illawarra blocks, a split-level design is almost always more cost-effective than cutting the site to a flat platform for a single-level home. Split-level design reduces earthworks and retaining costs, creates natural living zones, and produces outdoor spaces that are more interesting and liveable. The right structural approach depends on the specific site — EBG assesses this as part of the early feasibility conversation.

Start your project — $990 Design Your Happy Place session

If you have a sloping block in Tarrawanna, Bulli, Thirroul, Austinmer, or anywhere across the Illawarra, the $990 Design Your Happy Place session with Jaison Grassato is the right first step.

Book at evolutionbuildinggroup.com.au/design-your-happy-place

Jaison Grassato — 0413 717 823