How to Protect Grain from Moisture & Pests with PP Fabric Bunker Covers
Are you storing bulk grain and concerned about weather damage or pest intrusion? Whether you're working with wheat, sorghum, barley or maize, effective protection is essential to prevent spoilage, maintain quality, and reduce storage losses. One of the most reliable solutions used across Australia is grain bunker storage using PP fabric.
In this blog, we’ll explore how polypropylene (PP) fabric bunker covers offer a strong, breathable, and weather-resistant barrier for grain storage, helping you keep your harvest in top condition throughout the season.
What Is Grain Bunker Storage?
Grain bunker storage refers to storing bulk grain in open-air bunkers lined with ground sheets and covered with protective tarps or fabrics. It is widely used by farmers, cooperatives, and grain handlers during harvest time when silos may be full or when temporary storage is more cost-effective.
While this method is practical and scalable, it also exposes grain to environmental risks. Rain, humidity, UV exposure, birds, rodents, and insects can all affect grain quality if not properly managed. That’s where PP fabric bunker covers come in.
Why Use PP Fabric for Grain Bunker Storage?
Polypropylene (PP) fabric is a woven synthetic material known for its durability, moisture resistance, and flexibility. It is lightweight but strong, making it ideal for outdoor storage applications where both protection and ease of handling are critical.
Here’s why it’s widely used in grain bunker systems:
Moisture Resistance
PP fabric offers excellent water resistance, preventing rainfall or condensation from penetrating the stored grain. By keeping moisture out, it helps reduce the risk of mould growth, fermentation, and spoilage.
Breathability
While the material repels water, it still allows for limited airflow, helping reduce humidity buildup under the cover. This breathability is important for preventing condensation that can lead to rot or degradation.
UV Protection
Grain stored outdoors is exposed to intense sunlight, particularly in Australian conditions. PP fabric covers are UV stabilised to resist solar degradation, which helps maintain cover integrity over time and protects grain from heat damage.
Strength & Tear Resistance
Bunker covers need to withstand wind, loading stress, and handling during installation. PP fabric is woven for strength and tear resistance, ensuring that covers maintain their shape and function even in demanding conditions.
Cost-Effective
Compared to permanent storage structures or heavier industrial materials, PP fabric offers a practical balance between performance and affordability, especially for seasonal or short-term grain storage.
How PP Fabric Helps Prevent Pest Intrusion
Grain piles attract a wide range of pests—mice, rats, birds, and insects—especially when stored outdoors. PP fabric covers act as a physical barrier, helping to minimise pest access in several ways:
Sealed edges deter rodents and insects from crawling into gaps.
Tight-weave construction limits small insect entry.
Smooth surfaces make it harder for birds to land and peck through.
Heavy-duty eyelets & tie-down options ensure the fabric remains firmly anchored, reducing the chance of pests getting underneath.
For large-scale operations, pairing PP covers with proper site hygiene and perimeter baiting further supports pest prevention efforts.
Grain Loss & Spoilage: What’s at Stake?
Moisture and pests are the two leading causes of grain spoilage in bunker storage systems. Even small leaks or unsealed sections can lead to:
Mould and fungal growth that render grain unsuitable for human or animal consumption.
Germination inside the pile due to excess humidity.
Rodent contamination that causes direct loss and taints large volumes.
Structural collapse if water pools or covers tears under pressure.
The use of PP fabric bunker covers is a proactive measure to reduce these risks and help maintain compliance with storage standards. For growers or grain marketers, this helps preserve market value and prevents financial loss during the critical post-harvest period.
Key Features to Look for in a Quality PP Fabric Bunker Cover
Not all covers are made the same. When sourcing grain bunker storage using PP fabric, consider the following features to get the most protection:
UV stabilisation rated for Australian conditions.
Woven PP base with laminated coating for water resistance.
Custom sizing for different bunker widths and lengths.
Reinforced edges with eyelets for tie-down compatibility.
Durable seam construction to prevent water ingress at joins.
Some suppliers also offer coloured covers (e.g. silver or white) to reduce surface heat absorption or manage light reflection in exposed environments.
Installation Tips for Maximum Protection
Proper installation is just as important as the material itself. A PP fabric cover needs to be applied and secured correctly to be effective. Here are some tips:
Clear the site of any debris or sharp objects before laying down the base liner.
Overlap cover edges generously to prevent wind lift.
Use sandbags or tie-down straps to weigh down edges securely.
Avoid pooling by ensuring covers are taut and sloped to drain rainwater.
Inspect regularly after storms or high winds for signs of wear or shifting.
For large bunkers, planning for cover removal and reapplication during grain out-loading is also essential. Reusable covers made from PP fabric are ideal for seasonal operations, offering flexibility and cost savings over time.
Applications Beyond Grain
While this blog focuses on grain bunker storage using PP fabric, the material also sees wide use in other rural and industrial storage contexts, including:
Silage or hay covers.
Fertiliser and aggregate storage.
Equipment or machinery protection.
Ground covers to suppress weed growth.
For farmers, feedlot managers, and grain handlers, investing in quality PP fabric covers means improved protection and extended product life for stored goods.
Supporting Compliance & Food Safety
In the context of modern agricultural practices, maintaining hygiene and quality in grain storage aligns with industry compliance standards. Proper bunker storage supported by quality PP covers can help reduce the risk of contamination and improve traceability from paddock to customer.
This is particularly important when storing grain for human consumption, export contracts, or regulated animal feed products. Long-term relationships with grain buyers often depend on maintaining consistent quality across harvest cycles—and good storage practices are a major part of that.
Local Suppliers & Support for Grain Growers
If you’re looking for high-quality grain bunker storage using PP fabric, it’s worth working with a local supplier who understands regional weather patterns, pest pressures, and harvesting timeframes. Sourcing from within Australia also helps reduce lead times and supports faster delivery during the busy post-harvest period.
Whether you're managing grain across a single paddock or coordinating storage across multiple sites, locally made PP fabric covers can provide the durability and reliability needed for tough rural conditions.
Protect Your Grain with Australian-Made Covers
At Darling Downs Tarpaulins, we offer Australian-made PP fabric bunker covers that support grain protection from both moisture and pests. Our covers are manufactured for durability, UV stability, and long-term use across a wide range of on-farm storage applications. From planning your bunker layout to helping you choose the right fabric size and tie-downs, we’re here to support growers through every season.
Contact us today to explore our full range of PP fabric storage solutions and request a quote tailored to your grain storage needs.