Updated October 2026
Bonnet Bay's quiet cul-de-sacs step down toward the Woronora River, and nearly every yard in the suburb is terraced to carve flat living space out of the slope. Those terraces run on retaining walls, many of them original 70s builds that are due for replacement. We connect you with builders who handle tiered riverside blocks like these all the time.
Common wall situations in Bonnet Bay
Terraced backyards are the defining job: two, three or four tiers stepping down the block, usually a mix of timber, brick and stone added over the decades. When the lowest tier weakens, everything above it loads up. Driveway retaining on the steeper cul-de-sacs is the second category, and walls supporting paths and stairs down to the lower yard are the third. Damp shaded lower tiers near the river rot timber noticeably faster than the sunny upper ones.
Material options
Concrete sleepers are the usual pick for rebuilding tiers because they last in the damp and the posts can be set to suit stepped ground. Some owners keep sandstone or stone-faced walls on the visible tiers for the bushland look and use sleepers behind the scenes. Compare concrete sleeper walls and timber retaining walls.
What a wall costs in Bonnet Bay
Tiered blocks often mean stair-only access to the lower yard, and hand-carrying materials adds labour. Two tiers rebuilt together usually cost less than two separate projects. Treat early figures as guide pricing only and read the retaining wall cost guide.
Walls over 600mm high need approval (a CDC or DA). Walls up to 600mm can be exempt development if they meet the other criteria, such as setbacks and drainage, so check with Sutherland Shire Council first.
Frequently asked questions
Should I rebuild all my tiers at once or one at a time?
If more than one tier is failing, doing them together is usually cheaper per metre and avoids new walls loading old ones. A builder can stage it if budget demands.
My lower yard is only reachable by stairs. Is that a problem?
No, it is normal for Bonnet Bay. Builders price the carry into the quote and use materials suited to hand placement.
The bottom wall collapsed in the rain. What now?
Keep clear of it and get an assessment quickly, because the tiers above depend on it. Start at leaning or collapsed wall or retaining wall repairs for lesser damage.
Make the terraces solid again. Get a fast quote