Bunker Covers

Fleximake grain bunker covers are an affordable method to store and protect your harvest from the elements. Our high quality and high strength grain bunker covers are made in Australia from UV resistant coated fabric materials. We offer bunker tarps manufactured from a wide variety of first grade fabric materials. They meet Australian standards and are made to suit the harsh Australian weather conditions.
The seams of the grain bunker tarps are fully welded for water-proofing and increased strength. Fleximake grain bunker tarps and ground sheets are tear and abrasion resistant with high tensile strength which allows it to be tough, durable and affordable. We understand that you do not want to take chances with your season’s worth of hard work. We will make sure you have top quality grain bunker covers to protect your harvest.
We manufacture all our grain bunker covers and stockpile covers in Australia. We here at Fleximake have the fastest and most sophisticated plastic welding machines in Australia. The modern tech, high speed machines bring us the capability to guarantee you a fast delivery regardless of the size of the bunker cover. This also means that we can offer you very competitive prices as opposed to our direct competitors.
Fleximake agricultural tarps are widely used by independent Australian farmers and grain dealers in the agricultural sector. Our bunker covers are tested in the field and proven over many years. We are focused on providing extremely economical temporary grain storage solutions to manage seasonal supply and demand balance.
The Fleximake team will work with you to understand your needs and advise you on the best specification and size for your grain storage. We will make sure that you can get grain tarps that will perfectly suit your needs. When the time is critical, you can rely on Fleximake to deliver a solution on time.

Grain Cover Brochure

Bunker Cover Videos


Why Fleximake Grain Bunker Covers

  • High quality, durable, UV treated Australian made fabrics
  • Fully welded seams to ensure waterproofing
  • Manufactured using specialised fabric welding machines
  • Can supply ground sheets for your grain storage application
  • Australia wide delivery
  • Robust to withstand to extremes of Australian climate yet they are easy to handle
  • Excellent tensile strength to withstand pulling forces on field
  • Large sizes can be supplied in one piece to eliminate site joining
  • Best Prices in the market

Top Cover Fabric Materials

  • Landmark® 340
Landmark® is an environmental alternative to PVC that provides excellent mechanical performance at half the weight of PVC. Landmark® is the product of choice for bulk grain covers, with excellent 'lay flat' characteristics and superior resistance to flex cracking. This fabric comes with 5 year UV warranty
  • Landmark® +360
Landmark® +360 is the newest fabric variant in the range, featuring the same great functional benefits as Landmark® 340, with superior tear resistance and tensile performance. It is the most robust polypropylene grain bunker fabric available on the market today. This fabric comes with 5 year UV warranty
  • Canvacon® 5000Q0
Canvacon® 5000Q is a premium quality woven polyethylene based coated fabric suitable for smaller grain bunker applications. With a history of over 30 years in the Australian grain market, providing outstanding puncture and abrasion resistance to withstand the harshest of installation and environmental conditions. This fabric comes with 3 year UV warranty
  • GrainTuff® 320PE
GrainTuff ® 320PE tarpaulin is an economical heavy duty coated fabric that is especially designed to use as top cover of grain bunkers. This fabric comes with 3 year UV warranty.
  • GrainTuff® 610PVC
GrainTuff ® 610PVC is a heavy duty coated reinforced PVC fabric that is especially designed to use as top cover of grain bunkers. This fabric comes with 3 year UV warranty. Service life can be up to 5-years depending on the usage conditions.

Ground Sheet Fabric Materials

  • 9PP® 145
9PP® 145 is an economical woven polypropylene based coated fabric suited for bunker ground sheet applications.
  • Versatex®
Versatex® is a quality woven polypropylene based coated fabric suited for bunker ground sheet applications.
  • GrainTuff® 180PE
GrainTuff ® 180PE tarpaulin is a heavy duty coated fabric that is especially designed to use as ground sheet of grain bunkers.


Dimensions of Grain Bunker

One of the important factor to consider when your designing a grain bunker is the height of the grain bunker. The height of the grain bunker is limited by the stacking height capability of your grain handling equipment. Each grain type will form a heap related to its repose angle. Repose angles for each type grains are as follows


Wheat- Repose angle of 23° from horizontal
Barley, Sorghum, Chickpea, Rice, Soya Bean, Rye- Repose angle of 26° from horizontal
Oats- Repose angle of 30° with respect to horizontal


Grain Bunker

Grain Repose Angle


Cross-section of a bunker – Width

Cross-section of a bunker – Length
Following tables provide the dimensions of the top cover required for various grain types and bunker heights to achieve your storage requirement

Top Cover Dimensions for Wheat Bunkers

Repose angle of 23° with respect to horizontal.(750kg per cubic metre)
Height of side retaining walls, h(m)Bunker Height H(m)Top Cover Width (m) Top Cover Length (m)  Length (m) per 50t

Top Cover Dimensions for Barley, Sorghum, Chickpea, Rice, Soya Bean or Rye Bunkers

Repose angle of 26° with respect to horizontal.(650kg per cubic metre)
Height of side retaining walls, h(m)Bunker Height H(m)Top Cover Width (m) Top Cover Length (m)  Length (m) per 50t

Top Cover Dimensions for Oats Bunker

Repose angle of 30° with respect to horizontal.(400kg per cubic metre)
Height of side retaining walls, h(m)Bunker Height H(m)Top Cover Width (m) Top Cover Length (m)  Length (m) per 50t
Fleximake fold your bunker cover in “concertina” fashion prior to roll it on a pipe. This enable you to handle and install the bunker cover easily and quickly.
Tarp folded in Concertina fashion
Tarp rolled on a pipe


Grain Ring Tarps and Ground Sheets


In addition to flat rectangular grain covers, Fleximake also manufactures tarps for grain rings. Grain ring tarps are custom made with conical shape to suit the diameter of your grain ring and the repose angle of the grain you are storing. The tarps are fitted with heavy duty webbing straps for reliable and convenient tie-down.The ground sheets for grain rings are circular shaped to fit perfectly in to your grain ring.
Please contact us with dimensions of the grain ring and type of grain you are planning to store.

How to Manage Grain Quality

Managing the grain quality is important to avoid risk of your new season’s grain being rejected by the grain buyer. The quality of grain can be maintained by controlling moisture and pests in storage grain. Protecting the grain from moisture ensures high value of the grain. Low level of moisture in your stored grain helps subduing the growth of bacteria and fungi, and also reduces the breeding of insects and mites. Moisture levels can usually be controlled by loading the grain at low moisture content and controlling insects which create moisture at loading.


Bunker Covers

Philip Burrill from Stored Grain explains how to setup for bunker storage.

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