{"title":"50mm Width Concrete Sleepers","description":null,"products":[{"product_id":"blackwood-under-fence-plinth","title":"Blackwood Concrete Under-Fence Plinth 50mm","description":"\u003cp\u003e\u003cstrong\u003eThe Blackwood concrete under-fence plinth (2340×200×50mm) closes the gap beneath Colorbond and timber fences in a deep dark finish — keeping pets and soil in, weeds and erosion out, and protecting fences on reactive clay sites.\u003c\/strong\u003e Australian-made, delivered Australia-wide by Retaining Walls Direct.\u003c\/p\u003e\n\u003cp\u003e\u003cem\u003eWritten and product-checked by the Retaining Walls Direct team — supplying concrete retaining wall and fencing products across Australia. Last updated: June 2026.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch2\u003eBlackwood under-fence plinth 50mm\u003c\/h2\u003e\n\u003cp\u003eAn under-fence plinth is a slim concrete strip that seals the gap at the base of a fence (or tops a low retaining wall). The dark Blackwood finish suits black Colorbond and modern fence lines, and is especially useful on reactive clay where ground movement opens gaps under fences.\u003c\/p\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eSize\u003c\/th\u003e\n\u003ctd\u003e2340mm (L) × 200mm (H) × 50mm (thick)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFinish\u003c\/th\u003e\n\u003ctd\u003eBlackwood — dark charcoal\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eUse\u003c\/th\u003e\n\u003ctd\u003eUnder Colorbond \u0026amp; timber fences; reactive clay; top of low walls\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003ctd\u003eRetaining Walls Direct (Australian-made)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eWhy use an under-fence plinth?\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eSeals the gap under fences — contains pets, soil and mulch.\u003c\/li\u003e\n\u003cli\u003eStops weeds, erosion and washout along the fence line.\u003c\/li\u003e\n\u003cli\u003eProtects timber\/Colorbond fences from ground moisture.\u003c\/li\u003e\n\u003cli\u003eConcrete — won't rot, warp or attract termites like timber.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eComplete the job\u003c\/h3\u003e\n\u003cp\u003eBrowse \u003ca href=\"\/collections\/hardware-brackets-cleats-rwd\"\u003ebrackets \u0026amp; fixings\u003c\/a\u003e, \u003ca href=\"\/collections\/concrete-sleepers\"\u003econcrete sleepers\u003c\/a\u003e and \u003ca href=\"\/collections\/steel-posts\"\u003esteel posts\u003c\/a\u003e for the full system.\u003c\/p\u003e\n\n\u003ch3\u003eBuying with confidence\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAustralia-wide delivery\u003c\/strong\u003e with a same-day freight quote.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGoogle-reviewed service\u003c\/strong\u003e and trade support.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReturns:\u003c\/strong\u003e no change-of-mind on made-to-order heavy goods; cancellations before dispatch refunded within 5 business days; faulty\/incorrect always rectified — see our \u003ca href=\"\/pages\/returns-delivery-refund-policy\"\u003ereturns \u0026amp; delivery policy\u003c\/a\u003e.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003ca href=\"\/pages\/book-a-quote\"\u003eSend your postcode and quantities for a freight quote\u003c\/a\u003e, or \u003ca href=\"\/pages\/contact-retaining-wall-direct\"\u003econtact the team\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003ch3\u003eFrequently asked questions\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eWhat's an under-fence plinth for?\u003c\/strong\u003e\u003cbr\u003eIt closes the gap between the bottom of a fence and the ground.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat size and colour?\u003c\/strong\u003e\u003cbr\u003e2340×200×50mm in dark Blackwood.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan you deliver to me?\u003c\/strong\u003e\u003cbr\u003eWe deliver across most of Australia. \u003ca href=\"\/pages\/book-a-quote\"\u003eSend your postcode and quantities\u003c\/a\u003e for a freight estimate.\u003c\/p\u003e","brand":"Retaining Walls Direct","offers":[{"title":"2340x200x50mm","offer_id":52125643309336,"sku":"BLKW-UFP-2340","price":56.97,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0952\/5595\/3688\/files\/blackwood-under-fence-plinth-50mm.png?v=1782362262"},{"product_id":"under-fence-plinths","title":"Under Fence Plinths — Concrete | Plain, Timberlook \u0026 Composite","description":"\u003ch2\u003eConcrete Under-Fence Plinths — Seal the Gap, Stop Erosion, Contain Pets\u003c\/h2\u003e\n\n\u003cp\u003eAfter 50 years of building retaining walls and fencing systems across Australia, the under-fence plinth is one of the most underrated finishing products on any job. A concrete plinth laid at the base of your fence line does what no amount of backfill or gravel can — it permanently seals the gap between the fence and the ground, stopping soil washout, weed intrusion, pet escapes, and the ongoing maintenance headache of a fence that never quite sits flush with the ground.\u003c\/p\u003e\n\n\u003cp\u003eOur under-fence plinths are \u003cstrong\u003epre-stressed reinforced concrete\u003c\/strong\u003e, 50mm thick, Australian-made, and available in three finishes to match your fence style. They're the same product we specify on our own retaining wall and fencing jobs — not a compromise product, not a lightweight alternative.\u003c\/p\u003e\n\n\u003cp\u003e\u003cem\u003eProduct range reviewed and specified by the Retaining Walls Direct trade team. Last updated July 2026.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch3\u003eChoose Your Finish\u003c\/h3\u003e\n\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eFinish\u003c\/th\u003e\n\u003cth\u003eDimensions\u003c\/th\u003e\n\u003cth\u003eBest For\u003c\/th\u003e\n\u003cth\u003ePrice\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003ePlain\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e2350 × 200 × 50mm\u003c\/td\u003e\n\u003ctd\u003eColorbond, steel, or any fence where the plinth won't be visible\u003c\/td\u003e\n\u003ctd\u003e$51.60\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eTimberlook\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e2350 × 200 × 50mm\u003c\/td\u003e\n\u003ctd\u003eTimber paling, hardwood, or timber-look composite fences\u003c\/td\u003e\n\u003ctd\u003e$56.97\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eComposite\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e2380 × 200 × 50mm\u003c\/td\u003e\n\u003ctd\u003eComposite fence panel systems with specific rail spacing\u003c\/td\u003e\n\u003ctd\u003e$51.60\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cp\u003e\u003cstrong\u003eNot sure which finish to choose?\u003c\/strong\u003e Plain is the most popular — it sits below fence height and is rarely visible once installed. Timberlook suits any job where the plinth face is exposed and you want it to blend with a timber fence aesthetic. Composite is sized specifically for composite fence systems where the 2380mm length matches panel module spacing.\u003c\/p\u003e\n\n\u003ch3\u003eWhy Concrete — Not Timber or Plastic?\u003c\/h3\u003e\n\n\u003cp\u003eWe've seen timber plinths rot within 3–5 years in reactive clay soils, and plastic alternatives crack under ground movement. Pre-stressed reinforced concrete is the only material that genuinely lasts in Australian ground conditions — it won't rot, warp, crack under normal load, or attract termites. In reactive Class H clay soils (common across Brisbane, Western Sydney, and Melbourne's outer suburbs), concrete is the only sensible choice. It moves with the ground without failing.\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePre-stressed reinforcement\u003c\/strong\u003e — Steel strand tensioned through the concrete core reduces cracking under load and ground movement, unlike standard unreinforced concrete strips.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e50mm thickness\u003c\/strong\u003e — Sufficient structural depth to span between fence posts without sagging or cracking under soil pressure.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTermite-proof\u003c\/strong\u003e — No organic material. No termite risk. No treatment required.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eZero maintenance\u003c\/strong\u003e — Once installed, concrete plinths require no painting, sealing, or replacement for the life of the fence.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAustralian-made\u003c\/strong\u003e — Manufactured to Australian standards. Not an imported product.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat Problems Does an Under-Fence Plinth Solve?\u003c\/h3\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003ePet containment\u003c\/strong\u003e — Dogs and cats can't dig under or squeeze through a concrete plinth. The most common reason homeowners order these.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSoil and mulch washout\u003c\/strong\u003e — Stops garden bed soil, mulch, and gravel washing under the fence line during rain events.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeed intrusion\u003c\/strong\u003e — Eliminates the gap where weeds grow along the fence base — a persistent maintenance issue on any unsealed fence line.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eErosion on sloped sites\u003c\/strong\u003e — On sites with any fall, an open fence base allows water to channel under the fence and erode the soil profile. A plinth stops this.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReactive clay ground movement\u003c\/strong\u003e — On Class M and H clay sites, the ground moves seasonally. A concrete plinth moves with it without cracking or creating gaps, unlike timber or plastic alternatives.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFinishing a retaining wall top\u003c\/strong\u003e — Plinths are also used to cap the top of a low retaining wall where a fence sits above, creating a clean transition between wall and fence.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eInstallation Overview\u003c\/h3\u003e\n\n\u003col\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrepare the fence line\u003c\/strong\u003e — Ensure posts are set and the fence line is established. The plinth sits between posts at ground level.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eExcavate a shallow trench\u003c\/strong\u003e — Dig 50–100mm deep along the fence line to partially bury the plinth for a flush finish and to prevent it being kicked or shifted.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBed on compacted sand or gravel\u003c\/strong\u003e — Lay a 20–30mm bed of compacted sand or fine gravel for a level, stable base. Do not bed directly on reactive clay without a sand layer.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePosition the plinth\u003c\/strong\u003e — Slide the plinth between posts. The 2350mm length is designed to span standard 2400mm post centres with clearance for post flanges.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBackfill and compact\u003c\/strong\u003e — Backfill both sides and compact lightly. The plinth does not require fixing to posts in most residential applications.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003cp\u003e\u003cstrong\u003eNote:\u003c\/strong\u003e On sloped sites, plinths can be stepped down the slope in increments. Contact our team for advice on stepped plinth installation on sites with significant fall.\u003c\/p\u003e\n\n\u003ch3\u003eComplete Your Fence and Retaining Wall System\u003c\/h3\u003e\n\n\u003cp\u003eUnder-fence plinths work as part of a complete fencing and retaining wall system. Browse our related products:\u003c\/p\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003ca href=\"\/collections\/concrete-sleepers\"\u003e\u003cstrong\u003eConcrete Sleepers\u003c\/strong\u003e\u003c\/a\u003e — 40MPa, 50MPa, and 60MPa retaining wall sleepers in all finishes\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/collections\/steel-posts\"\u003e\u003cstrong\u003eSteel Retaining Wall Posts\u003c\/strong\u003e\u003c\/a\u003e — H-beam UC and C-channel PFC posts, galvanised\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/collections\/hardware-brackets-cleats-rwd\"\u003e\u003cstrong\u003eHardware, Brackets \u0026amp; Cleats\u003c\/strong\u003e\u003c\/a\u003e — Fence brackets, post caps, and fixings\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/collections\/drainage-kits-ag-pipe-weep-holes\"\u003e\u003cstrong\u003eDrainage Kits\u003c\/strong\u003e\u003c\/a\u003e — Ag pipe, geotextile, and weep holes for retaining walls\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/collections\/under-fence-plinths\"\u003e\u003cstrong\u003eUnder-Fence Plinths Collection\u003c\/strong\u003e\u003c\/a\u003e — Browse all plinth options including city-specific availability\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eFrequently Asked Questions — Under Fence Plinths\u003c\/h3\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat is an under-fence plinth?\u003c\/strong\u003e\u003cbr\u003e\nAn under-fence plinth is a pre-stressed reinforced concrete strip installed at the base of a fence line to seal the gap between the fence and the ground. It prevents soil washout, weed growth, pet escapes, and erosion. Standard size is 2350×200×50mm.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eHow long do concrete under-fence plinths last?\u003c\/strong\u003e\u003cbr\u003e\nProperly installed concrete plinths last the life of the fence — typically 30–50+ years in Australian conditions. Unlike timber (which rots in 3–5 years in clay soils) or plastic (which cracks under UV and ground movement), pre-stressed concrete is unaffected by moisture, termites, or seasonal ground movement.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eWhat is the difference between Plain, Timberlook, and Composite finishes?\u003c\/strong\u003e\u003cbr\u003e\nPlain has a smooth concrete face — best where the plinth won't be visible or for Colorbond fences. Timberlook has a moulded timber-grain texture on the face — suits timber paling or hardwood fences. Composite is 30mm longer (2380mm) to match composite fence panel module spacing.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eDo under-fence plinths need to be fixed to the fence posts?\u003c\/strong\u003e\u003cbr\u003e\nIn most residential applications, no. The plinth sits between posts in a shallow trench and is held in place by backfill and its own weight (approximately 55–60kg per plinth). On exposed or high-wind sites, a construction adhesive bead on the post face can be used for additional security.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCan under-fence plinths be used on sloped sites?\u003c\/strong\u003e\u003cbr\u003e\nYes — on sloped sites, plinths are stepped down the slope in increments matching the fall. Each plinth sits level within its bay, with the step occurring at each post. Contact our team for advice on your specific site gradient.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eHow many plinths do I need?\u003c\/strong\u003e\u003cbr\u003e\nOne plinth per fence bay (post to post). For a standard 2400mm post spacing, one 2350mm plinth fills each bay. Divide your total fence length by 2.4 to get the number of bays, then round up.\u003c\/p\u003e\n\n\u003ch3\u003eDelivery \u0026amp; Trade Pricing\u003c\/h3\u003e\n\n\u003cp\u003eWe deliver under-fence plinths Australia-wide via our crane truck and freight network. Plinths are heavy goods — freight is calculated by postcode and quantity. \u003ca href=\"\/pages\/book-a-quote\"\u003eSend your postcode and quantities for a same-day freight quote\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003cp\u003eTrade accounts and volume pricing available for builders, landscapers, and fencing contractors. \u003ca href=\"\/pages\/contact-retaining-wall-direct\"\u003eContact our team\u003c\/a\u003e to discuss trade pricing on your next project.\u003c\/p\u003e","brand":"Retaining Walls Direct","offers":[{"title":"Plain","offer_id":52287860015384,"sku":null,"price":51.6,"currency_code":"AUD","in_stock":true},{"title":"Timberlook","offer_id":52287860310296,"sku":null,"price":56.97,"currency_code":"AUD","in_stock":true},{"title":"Composite","offer_id":52287860343064,"sku":null,"price":51.6,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0952\/5595\/3688\/files\/concrete_plinth_stone_retaining_walls_direct_8d37c674-53a4-4654-b9e2-116497b8cfcf.jpg?v=1784782842"}],"url":"https:\/\/www.retainingwallsdirect.com.au\/collections\/50mm-width-concrete-sleepers.oembed","provider":"Retaining Walls Direct","version":"1.0","type":"link"}