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Bottom Seal vs Side Seal

Plastic bags are made by either side sealing or bottom sealing. Side seal bags are slightly cheaper and are usual for small size bags bottom seal bags are typically larger or for heavy duty applications. If you are unsure what type of bag you need call us and we will be sure to be able to help you decide.

Side Seal Bags

Side Seal bags are made using center fold film. The bag forming machine simultaneously cuts and seals the sides of the bag. Handles or air holes can be formed prior to the cutting and sealing operation, there are a number of variations on the side seal process.


Side sealing is used to make,

  • press seal bags
  • trade show bags
  • small and medium general purpose bags
  • bags with bottom gussets.

 Side seal bags are not as strong as bottom seal bags but they are cheaper to produce. Side seal bags are still very strong but they are not suitable for applications such as potting mix, potato bags etc.

Bottom Seal bags

Bottom Seal bags are made using lay flat tube. The bag forming machine seals the bag and cuts the bag just below the seal. Handles or air holes can be formed prior to the cutting and sealing operation. Bottom sealed bags are only stronger than side seal bags when used for carrying materials that flow, IE grain, flour, sand, pebbles, asphalt. For a heavy rigid item (eg a small motor) side seall bags are just as strong.

Bottom seal bags are extremely strong – a 150 micron bag loaded with 25 kg of plastic granules can survive a fall from over 3 meters. This test was forced upon us one day when our forklift broke down.

Bottom seal bags are used for heavy duty applications such as.
- Potting mix and pebbles.
- Onions, potatoes and carrots.
- Food bags that require a water-tight seal.
- Bags with side gussets for increased volume.

We have over a thousand customers, chances are one of them has a similar application to yours - give us a call and we'll help you finalize your requirements.