{"title":"Drainage","description":"\u003cp\u003eWater is the single biggest reason retaining walls fail. Soil that cannot drain builds hydrostatic pressure behind the wall, and that pressure sits on top of the earth pressure the wall was designed for. Drainage is a structural matter, not a finishing detail, and it is the part of a materials list people trim first.\u003c\/p\u003e\u003ch3\u003eDrainage gravel\u003c\/h3\u003e\u003cp\u003eFree draining aggregate in 10mm and 20mm, sold in bulk from 3m3 up to 10m3. The larger the load the cheaper the rate per cubic metre, so it pays to work out the whole wall before you order rather than topping up later.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much you need.\u003c\/strong\u003e Our calculator assumes a 300mm wide drainage zone running the full height and full length of the wall. On a 10 metre wall 1 metre high that is 3m3, which happens to be the smallest load we deliver. Double the height and you double the volume.\u003c\/p\u003e\u003cp\u003eTen millimetre gravel packs tighter and weighs about 1.68 tonnes per cubic metre. Twenty millimetre is more open and lighter at about 1.55 tonnes. Either works behind a wall. The 20mm drains a little faster, the 10mm is easier to shovel and rake into a narrow zone.\u003c\/p\u003e\u003ch3\u003eAgi pipe\u003c\/h3\u003e\u003cp\u003eThe pipe collects the water the gravel lets through and carries it to a legal discharge point. Available socked and unsocked, in 60mm, 65mm and 100mm, in 20m and 50m coils.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSize by wall height.\u003c\/strong\u003e 65mm suits walls up to 1m. Use 100mm at 1m and above, or on any wall where a lot of water drains toward it from uphill.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSocked or unsocked.\u003c\/strong\u003e The sock is a filter sleeve that keeps fines out of the pipe. We recommend socked for most walls. Unsocked is fine where the pipe sits inside a geo fabric wrap at the base of the aggregate, because the fabric is already doing the filtering.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOne run, full length.\u003c\/strong\u003e Lay it at the base of the drainage zone behind the bottom sleeper, and make sure it actually goes somewhere. A pipe that ends in the middle of the yard has just moved the problem.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003ePair the gravel and pipe with \u003ca href=\"\/collections\/geo-fabric\"\u003egeo fabric\u003c\/a\u003e so fines cannot migrate in and clog the zone. A blocked drain is the same as no drain.\u003c\/p\u003e\u003ch3\u003eTwo things to know before you order\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eDrainage gravel is delivery only.\u003c\/strong\u003e We supply and deliver it to your site and do not offer pickup for it.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eFire ants.\u003c\/strong\u003e Bulk gravel, sand and soil are regulated material under the South East Queensland fire ant movement controls, and those obligations apply to you as the receiver as well as to us. Read \u003ca href=\"\/pages\/delivery-installation\"\u003eDelivery and Installation\u003c\/a\u003e before you order.\u003c\/p\u003e\u003cp\u003eOur \u003ca href=\"\/blogs\/guides\/drainage-management\"\u003edrainage management guide\u003c\/a\u003e covers the build sequence and the \u003ca href=\"\/pages\/retaining-wall-drainage-guide\"\u003edrainage guide\u003c\/a\u003e sets out quantities per lineal metre.\u003c\/p\u003e","products":[{"product_id":"drainage-coil-agi-pipe-socked","title":"Drainage Coil Agi Pipe Socked","description":"\u003cp\u003eSocked agi pipe is the drainage line that runs along the base of your retaining wall. The pipe collects the water that makes it through the drainage gravel and carries it away to a discharge point, which is what keeps hydrostatic pressure off the back of the wall.\u003c\/p\u003e\n\u003cp\u003eThe sock is a geotextile filter sleeve bonded over the slotted pipe. It stops fines washing into the slots and silting the line up. \u003cstrong\u003eWe recommend socked pipe for most retaining walls.\u003c\/strong\u003e Use \u003ca href=\"\/products\/drainage-coil-agi-pipe-unsocked\"\u003eunsocked\u003c\/a\u003e only where the pipe sits inside a geo fabric wrap at the base of the aggregate, because the fabric is already doing the filtering.\u003c\/p\u003e\n\u003ch3\u003eWhich size\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e60mm and 65mm\u003c\/strong\u003e suit walls up to 1m high.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e100mm\u003c\/strong\u003e is for walls 1m and above, and for any wall where a lot of water drains toward it from uphill. If in doubt, go up a size. The cost difference is small against the cost of a failed wall.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eSize\u003c\/th\u003e\n\u003cth\u003eCoil length\u003c\/th\u003e\n\u003cth\u003eApprox weight\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e60mm\u003c\/td\u003e\n\u003ctd\u003e20m\u003c\/td\u003e\n\u003ctd\u003e4.8kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e60mm\u003c\/td\u003e\n\u003ctd\u003e50m\u003c\/td\u003e\n\u003ctd\u003e11.9kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e65mm\u003c\/td\u003e\n\u003ctd\u003e20m\u003c\/td\u003e\n\u003ctd\u003e5.1kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e100mm\u003c\/td\u003e\n\u003ctd\u003e20m\u003c\/td\u003e\n\u003ctd\u003e10.5kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e100mm\u003c\/td\u003e\n\u003ctd\u003e50m\u003c\/td\u003e\n\u003ctd\u003e26.4kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eWeights are based on published Vinidex Draincoil SN8 slotted pipe figures for the nearest equivalent nominal size, with an allowance added for the sock, which the manufacturer does not publish separately. They are a freight guide, not a certified figure. Coils are bulky rather than heavy, so delivery cost on agi pipe is usually driven by the space it takes on the truck.\u003c\/p\u003e\n\u003ch3\u003eHow much you need\u003c\/h3\u003e\n\u003cp\u003eOne run, the full length of the wall, plus enough to reach your discharge point. Order a little over rather than joining two coils in the middle of a trench. Our \u003ca href=\"\/pages\/retaining-wall-calculator\"\u003ewall calculator\u003c\/a\u003e works it out alongside your gravel and geo fabric.\u003c\/p\u003e\n\u003cdetails\u003e\u003csummary\u003eInstallation\u003c\/summary\u003e\u003cp\u003eThe pipe goes in before the gravel, at the very base of the drainage zone behind the bottom sleeper, sitting on a level or slightly graded bed so water runs to the outlet rather than sitting in a low spot. Line the excavation with \u003ca href=\"\/collections\/geo-fabric\"\u003egeo fabric\u003c\/a\u003e first, lay the pipe, backfill with \u003ca href=\"\/products\/10mm-and-20mm-drainage-gravel-aggregate\"\u003edrainage gravel\u003c\/a\u003e, then fold the fabric over the top.\u003c\/p\u003e\n\u003cp\u003eThink about where the water actually goes. A pipe that ends in the middle of the yard has moved the problem, not solved it. Our \u003ca href=\"\/blogs\/guides\/drainage-management\"\u003edrainage management guide\u003c\/a\u003e covers the sequence and the \u003ca href=\"\/blogs\/guides\/installation-cross-section-diagram\"\u003ecross section diagram\u003c\/a\u003e shows where it sits.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eDelivery Notes\u003c\/summary\u003e\u003cp\u003eDepending on the order size HYBUILT can usually deliver your materials within 2-3 business days after order confirmation. Agi pipe is light but bulky, so it is best added to an existing materials delivery rather than freighted on its own. To efficiently carry out these duties HYBUILT operates an entire fleet of crane trucks in a variety of sizes to suit both load size and\/or potential access constraints. Please note that there is delivery charges involved and this will depend on load size, distance and potential access constraints. We deliver to Brisbane, Gold Coast, Ipswich, Sunshine Coast, Toowoomba and Northern NSW\u003c\/p\u003e\u003c\/details\u003e\n\u003cp\u003eQuestions about your project? See our \u003ca href=\"\/blogs\/guides\"\u003einstallation guides\u003c\/a\u003e, \u003ca href=\"\/pages\/request-quote\"\u003erequest a quote\u003c\/a\u003e, or call \u003ca href=\"tel:0737160191\"\u003e(07) 3716 0191\u003c\/a\u003e.\u003c\/p\u003e","brand":"HYBUILT","offers":[{"title":"60mm Socked 20m","offer_id":53937787207791,"sku":"DRN-AGI-S-060-20","price":85.0,"currency_code":"AUD","in_stock":true},{"title":"60mm Socked 50m","offer_id":53937787240559,"sku":"DRN-AGI-S-060-50","price":170.0,"currency_code":"AUD","in_stock":true},{"title":"65mm Socked 20m","offer_id":53937787273327,"sku":"DRN-AGI-S-065-20","price":95.0,"currency_code":"AUD","in_stock":true},{"title":"100mm Socked 20m","offer_id":53937787306095,"sku":"DRN-AGI-S-100-20","price":165.0,"currency_code":"AUD","in_stock":true},{"title":"100mm Socked 50m","offer_id":53937787338863,"sku":"DRN-AGI-S-100-50","price":330.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0745\/7295\/5759\/files\/Drainage-Coil-Agi-Pipe-Socked-100mm.png?v=1785839604"},{"product_id":"drainage-coil-agi-pipe-unsocked","title":"Drainage Coil Agi Pipe Unsocked","description":"\u003cp\u003eUnsocked agi pipe is slotted corrugated drainage coil without the geotextile filter sleeve. It is the cheaper of the two, and it is the right choice in one specific situation: where the pipe sits inside a geo fabric wrap at the base of the drainage aggregate, so the fabric is already filtering out the fines.\u003c\/p\u003e\n\u003cp\u003eIf the pipe is going in without that wrap, order \u003ca href=\"\/products\/drainage-coil-agi-pipe-socked\"\u003esocked pipe\u003c\/a\u003e instead. An unsocked line laid straight against soil silts up, and a blocked drain is the same as no drain at all.\u003c\/p\u003e\n\u003ch3\u003eWhich size\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e60mm and 65mm\u003c\/strong\u003e suit walls up to 1m high.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e100mm\u003c\/strong\u003e is for walls 1m and above, and for any wall where a lot of water drains toward it from uphill.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eSize\u003c\/th\u003e\n\u003cth\u003eCoil length\u003c\/th\u003e\n\u003cth\u003eApprox weight\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e60mm\u003c\/td\u003e\n\u003ctd\u003e20m\u003c\/td\u003e\n\u003ctd\u003e4.3kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e60mm\u003c\/td\u003e\n\u003ctd\u003e50m\u003c\/td\u003e\n\u003ctd\u003e10.8kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e65mm\u003c\/td\u003e\n\u003ctd\u003e20m\u003c\/td\u003e\n\u003ctd\u003e4.6kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e100mm\u003c\/td\u003e\n\u003ctd\u003e20m\u003c\/td\u003e\n\u003ctd\u003e9.5kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e100mm\u003c\/td\u003e\n\u003ctd\u003e50m\u003c\/td\u003e\n\u003ctd\u003e24kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eWeights are based on published Vinidex Draincoil SN8 slotted pipe figures for the nearest equivalent nominal size. They are a freight guide, not a certified figure. Coils are bulky rather than heavy, so delivery cost on agi pipe is usually driven by the space it takes on the truck.\u003c\/p\u003e\n\u003ch3\u003eHow much you need\u003c\/h3\u003e\n\u003cp\u003eOne run, the full length of the wall, plus enough to reach your discharge point. Order a little over rather than joining two coils in the middle of a trench. Our \u003ca href=\"\/pages\/retaining-wall-calculator\"\u003ewall calculator\u003c\/a\u003e works it out alongside your gravel and geo fabric.\u003c\/p\u003e\n\u003cdetails\u003e\u003csummary\u003eInstallation\u003c\/summary\u003e\u003cp\u003eLine the excavation behind the wall with \u003ca href=\"\/collections\/geo-fabric\"\u003egeo fabric\u003c\/a\u003e in a U shape, lay the pipe at the base of that wrap, backfill with \u003ca href=\"\/products\/10mm-and-20mm-drainage-gravel-aggregate\"\u003edrainage gravel\u003c\/a\u003e, then fold the fabric over the top of the aggregate. That wrap is what makes unsocked pipe acceptable here.\u003c\/p\u003e\n\u003cp\u003eGrade the line so water runs to the outlet rather than sitting in a low spot, and make sure the outlet actually discharges somewhere it can go. Our \u003ca href=\"\/blogs\/guides\/drainage-management\"\u003edrainage management guide\u003c\/a\u003e covers the sequence and the \u003ca href=\"\/blogs\/guides\/installation-cross-section-diagram\"\u003ecross section diagram\u003c\/a\u003e shows where it sits.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eDelivery Notes\u003c\/summary\u003e\u003cp\u003eDepending on the order size HYBUILT can usually deliver your materials within 2-3 business days after order confirmation. Agi pipe is light but bulky, so it is best added to an existing materials delivery rather than freighted on its own. To efficiently carry out these duties HYBUILT operates an entire fleet of crane trucks in a variety of sizes to suit both load size and\/or potential access constraints. Please note that there is delivery charges involved and this will depend on load size, distance and potential access constraints. We deliver to Brisbane, Gold Coast, Ipswich, Sunshine Coast, Toowoomba and Northern NSW\u003c\/p\u003e\u003c\/details\u003e\n\u003cp\u003eQuestions about your project? See our \u003ca href=\"\/blogs\/guides\"\u003einstallation guides\u003c\/a\u003e, \u003ca href=\"\/pages\/request-quote\"\u003erequest a quote\u003c\/a\u003e, or call \u003ca href=\"tel:0737160191\"\u003e(07) 3716 0191\u003c\/a\u003e.\u003c\/p\u003e","brand":"HYBUILT","offers":[{"title":"60mm Unsocked 20m","offer_id":54028216565871,"sku":"DRN-AGI-U-060-20","price":55.0,"currency_code":"AUD","in_stock":true},{"title":"60mm Unsocked 50m","offer_id":54028216598639,"sku":"DRN-AGI-U-060-50","price":140.0,"currency_code":"AUD","in_stock":true},{"title":"65mm Unsocked 20m","offer_id":53937787666543,"sku":"DRN-AGI-U-065-20","price":60.0,"currency_code":"AUD","in_stock":true},{"title":"100mm Unsocked 20m","offer_id":53937787699311,"sku":"DRN-AGI-U-100-20","price":125.0,"currency_code":"AUD","in_stock":true},{"title":"100mm Unsocked 50m","offer_id":53937787732079,"sku":"DRN-AGI-U-100-50","price":230.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0745\/7295\/5759\/files\/Drainage-Coil-Agi-Pipe-Unsocked.png?v=1785839608"},{"product_id":"10mm-and-20mm-drainage-gravel-aggregate","title":"10mm and 20mm Drainage Gravel \/ Aggregate","description":"\u003cp\u003e\u003cstrong\u003e10mm and 20mm drainage gravel\u003c\/strong\u003e is a tough, crushed rock that lets water move through quickly, making it ideal for any job where you need reliable drainage. It's commonly used to fill trenches, pack around ag‑pipes, and sit behind retaining walls to take pressure off the structure. Because it's free‑draining and doesn't break down, it helps stop waterlogging, reduces erosion, and keeps the area stable over time.\u003c\/p\u003e\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cp\u003eTo work out how much drainage gravel you require (volume) of cubic meters (m3), use the following equation: Wall Length x Drainage Hole Width (we recommend 300mm) x Wall Height\u003c\/p\u003e\n\u003cdetails\u003e\u003csummary\u003eInstallation\u003c\/summary\u003e\u003cp\u003eHYBUILT have partnered with only the most experienced installers across South East Queensland and Northern NSW, offering a complete design \u0026amp; construct solution through competitive pricing and innovation. Enquire with our team to book your next project.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eDelivery Notes\u003c\/summary\u003e\u003cp\u003eWe supply and deliver the drainage gravel to your site. We do not provide pick up options. The price shown covers the gravel and delivery to local areas within the northern and southern suburbs of Brisbane. Beyond those suburbs a delivery surcharge applies. Any delivery rate shown at checkout is indicative only, and our team confirms the final delivery cost for your delivery address before your order is dispatched, so there is no freight surprise after you have paid. We can deliver within the radius of the regions of the Sunshine Coast, Kingaroy, Toowoomba, Warwick, the Gold Coast and Northern NSW.\u003c\/p\u003e\n\u003cp\u003eDepending on the order size HYBUILT can usually deliver your materials within 2-3 business days after order confirmation. To efficiently carry out these duties HYBUILT operates an entire fleet of crane trucks in a variety of sizes to suit both load size and\/or potential access constraints. Any delivery surcharge beyond local Brisbane depends on load size, distance and potential access constraints. We deliver to Brisbane, Gold Coast, Ipswich, Sunshine Coast, Toowoomba and Northern NSW\u003c\/p\u003e\u003c\/details\u003e\n\u003cp\u003eQuestions about your project? See our \u003ca href=\"\/blogs\/guides\"\u003einstallation guides\u003c\/a\u003e, \u003ca href=\"\/pages\/request-quote\"\u003erequest a quote\u003c\/a\u003e, or call \u003ca href=\"tel:0737160191\"\u003e(07) 3716 0191\u003c\/a\u003e.\u003c\/p\u003e","brand":"HYBUILT","offers":[{"title":"3m3 of 10mm","offer_id":53937788715119,"sku":"DRN-GRV-10-03","price":390.0,"currency_code":"AUD","in_stock":true},{"title":"4m3 of 10mm","offer_id":53937788747887,"sku":"DRN-GRV-10-04","price":470.0,"currency_code":"AUD","in_stock":true},{"title":"5m3 of 10mm","offer_id":53937788780655,"sku":"DRN-GRV-10-05","price":520.0,"currency_code":"AUD","in_stock":true},{"title":"6m3 of 10mm","offer_id":53937788813423,"sku":"DRN-GRV-10-06","price":590.0,"currency_code":"AUD","in_stock":true},{"title":"7m3 of 10mm","offer_id":53937788846191,"sku":"DRN-GRV-10-07","price":650.0,"currency_code":"AUD","in_stock":true},{"title":"8m3 of 10mm","offer_id":53937788878959,"sku":"DRN-GRV-10-08","price":710.0,"currency_code":"AUD","in_stock":true},{"title":"9m3 of 10mm","offer_id":53937788911727,"sku":"DRN-GRV-10-09","price":770.0,"currency_code":"AUD","in_stock":true},{"title":"10m3 of 10mm","offer_id":53937788944495,"sku":"DRN-GRV-10-10","price":830.0,"currency_code":"AUD","in_stock":true},{"title":"3m3 of 20mm","offer_id":53937788977263,"sku":"DRN-GRV-20-03","price":390.0,"currency_code":"AUD","in_stock":true},{"title":"4m3 of 20mm","offer_id":53937789010031,"sku":"DRN-GRV-20-04","price":470.0,"currency_code":"AUD","in_stock":true},{"title":"5m3 of 20mm","offer_id":53937789042799,"sku":"DRN-GRV-20-05","price":520.0,"currency_code":"AUD","in_stock":true},{"title":"6m3 of 20mm","offer_id":53937789075567,"sku":"DRN-GRV-20-06","price":590.0,"currency_code":"AUD","in_stock":true},{"title":"7m3 of 20mm","offer_id":53937789108335,"sku":"DRN-GRV-20-07","price":650.0,"currency_code":"AUD","in_stock":true},{"title":"8m3 of 20mm","offer_id":53937789141103,"sku":"DRN-GRV-20-08","price":710.0,"currency_code":"AUD","in_stock":true},{"title":"9m3 of 20mm","offer_id":53937789173871,"sku":"DRN-GRV-20-09","price":770.0,"currency_code":"AUD","in_stock":true},{"title":"10m3 of 20mm","offer_id":53937789206639,"sku":"DRN-GRV-20-10","price":830.0,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0745\/7295\/5759\/files\/Drainage-Gravel.png?v=1785839623"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0745\/7295\/5759\/collections\/Drainage-Coil-Agi-Pipe-Socked-100mm.png?v=1785839205","url":"https:\/\/hybuilt.com.au\/collections\/drainage.oembed","provider":"HYBUILT","version":"1.0","type":"link"}