The 150mm concrete under-fence plinth is the widest section in our range — built for the jobs where a 100mm plinth isn't quite enough. After many years on the tools, I reach for the 150mm in three situations: steep sloped sites where stepping creates large exposed gaps between bays, pool fence installs where the certifier wants maximum compliance margin with zero risk of a failed inspection, and commercial or rural fence lines where the ground profile is inconsistent and you want one width that covers everything without mixing sections.
We supply and install concrete plinths across Australia under AS 4678-2002 and AS 1926.1-2012. Every plinth is precast, steel-reinforced where required, and available in finishes that match our full concrete sleeper retaining wall range — so your fence base and retaining wall can present as a cohesive system.
Available in plain grey, timberlook (woodgrain texture), and composite finishes — the same colour and texture range as our 50mm and 100mm plinths so you can mix widths on the same fence line without a visible mismatch.
These are the site conditions where I consistently specify 150mm over 100mm:
150mm plinths are priced per linear metre and vary by finish and length. As a general guide, expect to pay 10–15% more per metre than the equivalent 100mm section — the additional width adds material cost but reduces installation time on sloped sites by cutting the number of steps required. Freight is calculated to your postcode at checkout before you pay. For trade and volume pricing, contact our team.
The maximum allowable gap under a pool barrier in Australia is 100mm under AS 1926.1-2012. A 150mm plinth exceeds this requirement on flat ground, providing a 50mm compliance buffer. This matters most on sites where the ground is not perfectly flat — on a site with even 10mm of undulation across a fence bay, a 100mm plinth may just pass or just fail depending on where the inspector measures; a 150mm plinth eliminates that uncertainty entirely.
State pool safety authority links: QBCC Pool Safety (QLD) — VBA Swimming Pools (VIC) — NSW Fair Trading Pool Safety — WA Building Commission (Swimming Pools)
The 150mm plinth installs identically to the 100mm section — the wider base requires a slightly wider trench and more mortar haunching. On sloped sites the wider plinth meaningfully reduces the number of step-downs required, cutting installation time on long runs.
Choose 150mm when: the gap under your fence exceeds 100mm at any point, your site is steeply sloped and stepping with 100mm plinths creates large exposed gaps, your pool fence certifier requires maximum compliance margin, or you want one consistent plinth width across a fence line with a variable ground profile rather than mixing sections. On sloped acreage and rural sites, 150mm is often the most cost-effective choice because it reduces the number of steps and on-site measuring required.
On flat ground with continuous, correctly haunched installation and no gaps at joins, yes — a 150mm plinth eliminates the gap entirely and exceeds AS 1926.1-2012's 100mm maximum. On sloped sites, stepped installation is still required — the plinth must not be tilted to follow the grade. Always have a licensed pool fence inspector verify the installation before the pool is filled and in use. Links to state authorities are above.
Under AS 1926.1-2012, the maximum allowable gap under a pool barrier is 100mm. This applies to all states and territories. A 150mm concrete plinth correctly installed on flat ground brings the gap to zero, providing a 50mm buffer against measurement variation. On sloped sites, the gap must be measured at the highest point of each fence bay.
Yes — this is common on sites where most of the fence line suits 100mm but specific bays have a larger gap. The two widths butt together cleanly at any point along the fence run. The difference in face height between a 100mm and 150mm section is 50mm — visible on close inspection but acceptable in most residential and commercial installations.
150mm plinths cost approximately 10–15% more per linear metre than equivalent 100mm sections. Exact pricing depends on finish (plain, timberlook, composite) and delivery location. Freight is calculated at checkout to your postcode before you pay. For trade or volume pricing, contact our team with your fence line length and we'll respond within one business day.
No — concrete is unaffected by moisture, UV, and ground contact and performs without any surface treatment. A penetrating concrete sealer can be applied after 28 days full cure to enhance the colour or protect against surface staining on street-facing or high-traffic fence lines. No painting is required or recommended.
