A silage bunker or pile may be sealed, but storage losses can still develop if the cover is damaged or loses contact with the crop. A loose edge, punctured film, or displaced weight can let air in before any spoilage is visible.
The storage phase begins after fermentation and continues until the bunker or pile is opened. Silage should remain stable during this period, with very little microbial activity. This depends on maintaining anaerobic conditions throughout the clamp.
Routine inspection is therefore a control measure, not a cosmetic check. It gives the farm an opportunity to find and repair damage before oxygen ingress causes wider dry matter and feed-value losses.
Key takeaways
· Assign responsibility for bunker inspections and include them in the farm schedule.
· Inspect the surface, shoulders, perimeter, sheet overlaps, and weighting system.
· Complete an additional check after high winds, heavy rain, hail, or nearby machinery work.
· Repair film damage promptly with a compatible silage patching product.
· Record defects, repairs, and repeated problem areas so corrective action can be taken.
Why silage can be lost after the bunker or pile is sealed
During stable storage, the pH should remain relatively constant and microbial activity should be low. Oxygen changes these conditions. It allows yeasts and molds to use sugars, fermentation acids, and other nutrients, releasing carbon dioxide and heat.
This process reduces the dry matter and energy available for feeding. It can also leave the silage less stable when the clamp is opened. Visible mold is a late sign. Losses may already have occurred beneath an apparently sound cover.
Air most often enters through damaged film, loose overlaps, inadequately sealed edges or areas where the covering system has lifted away from the crop. The top, shoulders and wall junctions need particular attention because they are close to exposed surfaces and can be harder to seal consistently.
How often should a silage bunker or pile be inspected?
There is no single inspection interval that suits every farm. Set the frequency according to the site, storage period, weather exposure, surrounding trees, bird and rodent activity, and the level of vehicle movement nearby.
As a minimum control, include the silo in routine farm checks and inspect it again after any event that could affect the covering system. This includes high winds, heavy rain, hail, falling branches, animal activity, and work by machinery close to the area.
Nominate a responsible person and provide a simple inspection record. If the usual inspector is absent, assign the check to another competent person rather than allowing a gap in control.
Silage pile inspection checklist
1. Check the complete top surface
View the full surface from a safe position. Look for punctures, tears, abrasion, lifted cover sections, and areas where the film appears loose. Check whether wind has moved the protective cover or exposed the sealing film beneath it.
The oxygen barrier film should remain close to the crop surface. The protective cover or net should shield it from birds, weather and physical damage. Correct local movement before it places more strain on the film or adjoining overlaps.
2. Inspect the perimeter, shoulders, and wall junctions
Walk the accessible perimeter and check that the covering materials remain sealed and securely weighted. Look for gaps where the film has pulled away from a wall, lifted at a corner, or lost contact around the shoulder.
Pay attention to areas where the crop profile changes. Uneven shoulders can leave channels beneath the sheet. Once air enters at an edge, it can move further into areas with lower density or poor film contact.
AHDB research on 20 English grass-silage bunkers found that the zone within 0.5 meters (1.5 feet) of the top sheet or side wall represented, on average, 27% of bunker volume. The study was not a corn assessment, so the figure should not be treated as a universal benchmark. It does show that a substantial amount of forage can sit close to vulnerable surfaces.
3. Check sheet overlaps and cover joints
Inspect every visible overlap and joint. The films should remain in the installed position, with no opening, folding, or wind movement that could create a route for air or rainwater.
Silostop's bunker-silo guidance specifies at least 1 meter/ 3 feet of overlap when more than one top-film roll or protective cover is used. Maintain the overlap and weighting pattern set out for the selected product. Do not assume that an overlap remains sealed because it was secure on the day of covering.
4. Confirm that weights remain complete and correctly positioned
Check gravel bags, tires, mats, and other weights for damage or movement. Replace split bags and return displaced weights to the specified position. Pay particular attention to the perimeter, overlaps, and areas exposed to prevailing winds.
Silostop's recommended bunker-silo method uses touching rows of gravel bags around the perimeter and along joins, with a cross-hatched pattern over the surface. Follow the current installation instructions for the film, cover, and pile layout being used.
Avoid leaving large unsupported areas. A few isolated weights may hold the sheet locally, but they do not stop air moving beneath a lifted cover.
5. Look for water pooling and drainage problems
Check whether rainwater is collecting on the covering system or directed towards the bunker edge. Water can place additional strain on films and covers, move weights, and make later access hazardous.
Do not puncture the film to release pooled water. Remove water using a safe method that does not damage the sealing layer. Check nearby gutters, channels and drains for blockages, then correct the cause where possible.
Silage effluent and contaminated runoff must continue to enter the correct collection system. Keep access routes clear so tanks, pumps and drainage controls can be checked without disturbing the silage cover.
6. Check for bird, rodent, and other animal damage
Look for peck holes, claw marks, burrows, droppings, and repeated activity at the same edge or corner. Birds and rodents can damage both the protective layer and the oxygen barrier film beneath it.
Repair the film and address the cause. Reposition the protective cover, remove nearby feed residues, and apply suitable pest controls within the farm's legal and environmental requirements. Repeated damage should trigger a review of the protection and weighting system- Silostop offers both Anti-UV Covers and Secure Covers for additional physical protection from the elements and animal damage.
7. Control machinery and site activity around the clamp
Check for damage caused by loader buckets, trailer components, forks, branches, or materials stored beside the bunker. Keep machinery routes and storage areas far enough away to prevent accidental contact with the covering system.
Restrict access to people who understand the covering layout and site controls. If work must take place near the silage pile, brief operators on the exclusion area and inspect the cover again when the task is complete.
8. Repair defects and record the action
Repair small holes as soon as they are found. Use patch tape designed for silage film. Clean and dry the area where conditions allow, then extend the patch onto sound film around the complete defect. Press it down securely and check the bond.
Keep silage tape in a dedicated inspection kit with spare film, replacement Gravel bags and safe cutting tools. This allows minor repairs to be completed during the same inspection.
A larger tear, failed joint or widespread movement may require partial resealing. Follow the product instructions and seek technical advice if the correct repair is uncertain. Avoid opening a wider area of film than the repair requires.
Inspect safely
Silo inspection can involve work near drops, unstable edges, slippery covers and stored machinery. Complete as much of the check as possible from safe ground. Do not walk onto the pile unless access has been assessed, and a safe system of work is in place.
Keep people away from unsupported overhangs and unstable faces. Use suitable access equipment where required. A defect in the cover does not justify uncontrolled access to a high-risk area.
What should an inspection record include?
The record does not need to be complicated. It should provide enough information to confirm that the inspection took place and that identified defects were controlled.
· storage area inspected.
· Date, time and name of the inspector.
· Weather conditions or event that triggered the check.
· Location and description of each defect.
· Immediate repair or control applied.
· Materials used and any follow-up work required.
· Date the repair was checked again.
Review the records before the next harvest. Repeated failures at the same corner, overlap, or shoulder may indicate a problem with bunker profile, film sizing, weighting, pest control or nearby operations. Correcting the cause is more effective than repeating the same repair each year.
Final storage inspection checklist
· Top surface free from punctures, tears and exposed film.
· Perimeter, shoulders and wall junctions remain sealed.
· Sheet overlaps and protective-cover joins remain closed and weighted.
· Gravel bags, tires or mats are intact and correctly positioned.
· No unmanaged water pooling or blocked drainage routes.
· Bird, rodent and other animal damage checked and controlled.
· Machinery and stored materials kept clear of the cover.
· Repairs completed with compatible materials and recorded.
· Follow-up inspection assigned where further work is required.
Protect the crop throughout storage
The cost of producing silage has already been incurred by the time the bunker or pile is sealed. Storage inspections protect that investment by keeping small defects from becoming wider losses.
A complete covering system remains essential. The oxygen barrier film limits oxygen transmission, the protective cover reduces physical damage, and the weighting system keeps the materials in position. Routine checks confirm that these components continue to work together.
Silostop Agri supplies oxygen barrier films, Secure Covers, and Gravelbags for complete silage covering systems. Contact the Silostop Agri team for support with film sizes, cover selection, weighting, and technical support.