{"product_id":"post-mix-bags-20kg","title":"Post Mix Bags 20kg","description":"\u003ch2\u003ePost Mix Bags 20kg\u003c\/h2\u003e\n\n\u003cp\u003ePost Mix Bags 20kg are a convenient premixed concrete solution for setting posts quickly and consistently. Designed for simple non-structural concrete work, this ready-to-use mix is ideal for fence posts, clothes lines, garden lights, letterbox posts, small poles, and general landscaping applications where a strong post footing is required.\u003c\/p\u003e\n\n\u003cp\u003eEach bag contains a carefully blended mix of Portland cement, graded aggregates, and admixtures. Simply add clean water as directed and use the mix around the post hole to create a stable footing. Post mix is a practical choice for fencing, garden, and retaining wall preparation jobs where bagged concrete is easier than mixing separate cement, sand, and aggregate on site.\u003c\/p\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct type:\u003c\/strong\u003e Post mix concrete bag\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBag size:\u003c\/strong\u003e 20kg\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Premixed blend of Portland cement, graded aggregates, and admixtures\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCoverage:\u003c\/strong\u003e Approximately 10 litres of concrete per 20kg bag\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eVolume:\u003c\/strong\u003e 1 bag equals approximately 0.01 cubic metre\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBulk conversion:\u003c\/strong\u003e Approximately 100 bags equals 1 cubic metre\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTypical usage:\u003c\/strong\u003e Approximately two 20kg bags per post hole, depending on hole size and site conditions\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplications:\u003c\/strong\u003e Fence posts, clothes lines, garden lights, letterbox posts, small poles, swings, and general outdoor post installation\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBest use:\u003c\/strong\u003e Simple non-structural post-setting and landscape fixing work\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eTechnical Overview\u003c\/h3\u003e\n\n\u003cp\u003ePost mix is designed to make small concrete jobs faster and easier. Instead of separately measuring cement, sand, aggregate, and additives, the dry components are already blended in the bag. This helps improve consistency and reduces preparation time on site, especially for fencing, landscaping, and post-setting projects.\u003c\/p\u003e\n\n\u003cp\u003eFor post holes, the bagged mix is typically placed around the positioned post and combined with clean water according to the product directions. Once hydrated and compacted correctly, the mix forms a concrete footing that helps hold the post in place. The final strength and stability of the post still depend on correct hole depth, hole diameter, soil condition, post alignment, and curing conditions.\u003c\/p\u003e\n\n\u003ch3\u003ePost Mix vs Rapid Set Concrete\u003c\/h3\u003e\n\n\u003cp\u003ePost mix is a practical option for general post-setting work where convenience and consistency are the main priorities. Rapid set concrete is usually chosen when faster hardening time is required, such as jobs where posts need to be secured quickly and site downtime must be reduced.\u003c\/p\u003e\n\n\u003cp\u003eFor standard fence posts, letterboxes, garden lights, and general landscaping work, post mix is often suitable. For time-sensitive installations or jobs requiring quicker set times, rapid set concrete may be the better choice.\u003c\/p\u003e\n\n\u003ch3\u003eWhy Use Post Mix Bags?\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eReady to use:\u003c\/strong\u003e Premixed cement, aggregate, sand, and admixtures reduce preparation time.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConvenient 20kg bag:\u003c\/strong\u003e Easier to transport, store, and calculate for small jobs.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGood for post holes:\u003c\/strong\u003e Suitable for fence posts, clothes lines, letterboxes, garden lights, and similar outdoor posts.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConsistent blend:\u003c\/strong\u003e Factory-mixed ingredients help avoid guesswork on site.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUseful for landscaping:\u003c\/strong\u003e Practical for garden, fencing, and boundary projects.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSimple volume calculation:\u003c\/strong\u003e Each 20kg bag produces approximately 10 litres of concrete.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eCommon Applications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eFence post installation\u003c\/li\u003e\n\u003cli\u003eClothes line footings\u003c\/li\u003e\n\u003cli\u003eLetterbox posts\u003c\/li\u003e\n\u003cli\u003eGarden light posts\u003c\/li\u003e\n\u003cli\u003eSmall outdoor poles\u003c\/li\u003e\n\u003cli\u003eSwings and small backyard fixtures\u003c\/li\u003e\n\u003cli\u003eLandscape edging supports\u003c\/li\u003e\n\u003cli\u003eGeneral garden and fencing projects\u003c\/li\u003e\n\u003cli\u003eSelected retaining wall post preparation where suitable for the wall design\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eUsing Post Mix for Retaining Wall Posts\u003c\/h3\u003e\n\n\u003cp\u003ePost mix may be suitable for selected retaining wall post holes where the wall design, footing size, and site conditions allow it. For concrete sleeper retaining walls, footing requirements depend on wall height, post type, post spacing, soil type, drainage, surcharge loads, and engineering requirements.\u003c\/p\u003e\n\n\u003cp\u003eAs a practical guide, a standard post hole may require more than one bag. The source product information notes approximately two 20kg bags per post hole, but the actual quantity should always be calculated from the hole diameter and depth. Taller retaining walls, deeper holes, larger diameter footings, or uneven excavation may require additional bags.\u003c\/p\u003e\n\n\u003cp\u003eFor engineered retaining walls, walls over 1.0m, clay soils, driveways, fences above the wall, or walls close to structures, always follow the engineer’s nominated concrete strength, footing depth, hole diameter, post size, and installation method.\u003c\/p\u003e\n\n\u003ch3\u003eInstallation Considerations\u003c\/h3\u003e\n\n\u003cp\u003eBefore adding post mix, dig the hole to the correct depth and diameter for the post being installed. Position the post carefully, check alignment, and brace it if needed before placing the mix. Add clean water according to the product directions and keep the post stable while the concrete sets and cures.\u003c\/p\u003e\n\n\u003cp\u003eDo not rely on post mix to compensate for poor footing design, shallow holes, weak soil, incorrect post spacing, or poor drainage. For retaining wall systems, the concrete footing works together with the steel post, sleepers, backfill, and drainage system to resist soil pressure.\u003c\/p\u003e\n\n\u003ch3\u003eCompatible Products\u003c\/h3\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eRapid setting alternative:\u003c\/strong\u003e \u003ca href=\"\/products\/rapid-set-bags-20kg-25mpa\"\u003eRapid Set Bags 20kg 25MPa\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard C-channel post option:\u003c\/strong\u003e \u003ca href=\"\/products\/galvanised-steel-c-posts-100mm-100pfc\"\u003eGalvanised Steel C Posts – 100mm 100PFC\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeavy-duty C-channel post option:\u003c\/strong\u003e \u003ca href=\"\/products\/galvanised-steel-c-posts-150mm-150pfc\"\u003eGalvanised Steel C Posts – 150mm 150PFC\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStandard H post option:\u003c\/strong\u003e \u003ca href=\"\/products\/galvanised-steel-h-posts-100mm-100uc-uc-14-8\"\u003eGalvanised Steel H Posts 100mm 100UC – UC 14.8\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeavy-duty H post option:\u003c\/strong\u003e \u003ca href=\"\/products\/galvanised-steel-h-posts-150mm-uc23-4\"\u003eGalvanised Steel H Posts 150mm UC23.4\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConcrete sleeper range:\u003c\/strong\u003e \u003ca href=\"\/collections\/concrete-sleepers\"\u003eConcrete Retaining Wall Sleepers\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eGuides and Resources\u003c\/h3\u003e\n\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFooting depth guide:\u003c\/strong\u003e \u003ca href=\"\/blogs\/news\/retaining-wall-footings-depth-concrete\"\u003eRetaining Wall Footings: Depth, Size and Concrete Guide\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterials calculator guide:\u003c\/strong\u003e \u003ca href=\"\/blogs\/news\/how-to-calculate-sleepers-posts-retaining-wall\"\u003eHow to Calculate Sleepers and Posts for a Retaining Wall\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eInstallation guide:\u003c\/strong\u003e \u003ca href=\"\/blogs\/news\/how-to-build-concrete-sleeper-retaining-wall\"\u003eHow to Build a Concrete Sleeper Retaining Wall\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePost spacing guide:\u003c\/strong\u003e \u003ca href=\"\/blogs\/news\/retaining-wall-post-spacing-guide\"\u003eRetaining Wall Post Spacing Guide\u003c\/a\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDrainage guide:\u003c\/strong\u003e \u003ca href=\"\/blogs\/news\/retaining-wall-drainage-guide\"\u003eRetaining Wall Drainage Guide\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eDelivery\u003c\/h3\u003e\n\n\u003cp\u003ePost Mix Bags 20kg are available for delivery across Sydney, Melbourne, Brisbane, Perth, Adelaide, Canberra, Gold Coast, and regional Australia. \u003ca href=\"\/pages\/book-a-quote\"\u003eGet a free quote\u003c\/a\u003e for your retaining wall, fencing, or landscaping materials.\u003c\/p\u003e\n","brand":"Retaining Walls Direct","offers":[{"title":"Default Title","offer_id":52288018907416,"sku":null,"price":15.3,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0952\/5595\/3688\/files\/QPro_2025_PostMixBags20kg-600x600.webp?v=1781591568","url":"https:\/\/www.retainingwallsdirect.com.au\/products\/post-mix-bags-20kg","provider":"Retaining Walls Direct","version":"1.0","type":"link"}