If you've spent any time browsing tents and waterproof jackets online, you'll often see the phrase 'fully taped seams' listed among the features. The next question that popped into your head might have been: "what are taped seams?"
Usually, when it comes to outdoor gear, we think of tape as something that's required when something has gone wrong, not something that you expect to see Arc'teryx or Rab adding to their premium jackets at the manufacturing stage. Yet seam tape has become a crucial part of the creation of the world's best waterproof jackets, tents, rain pants – in fact, pretty much any waterproof gear.
In this article, we reveal all you need to know about seam sealing, from how it's done and why it’s necessary, all the way through to the role sealed seams play in keeping you dry on your hiking and camping adventures.
Meet the expert
Kieran, our esteemed former editor, is a passionate rock climber, avid explorer and expert on kit for the great outdoors. After a spell in Italy, he now loves hitting the crags and mountains of his Scottish home, though it's rare that he has a day where his waterproofs aren't called for.
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What are taped seams? A definition
- Seam taping is a method employed by manufacturers to waterproof the part where seams of fabrics meet
- This would otherwise be a weak point in terms of weather resistance
- There are three types: critically taped seams, fully taped seams and welded seams.
In short, seam taping is a method employed by outdoor gear manufacturers – in everything from the best tents and waterproof jackets to gaiters and tarps – to improve waterproofing in gear by doubling down on protection in the fabric’s most significant point of weakness, i.e. the seams. When any product is made with multiple pieces of fabric, the pieces are sewn together, thus creating a “seam”. In the process of stitching the pieces of fabric together, hundreds – if not thousands – of tiny holes are created, thus leaving a potential entry point for water. Back in the day, outdoors-goers got around this problem by applying water-resistant waxes and oils to the seams, but seam taping is more effective, more durable, and saves you both a lot of hassle and having to put up with the (usually) funky smells of those oils and waxes.
Types of taped seams
There are three different types of taped seams: critically taped seams, fully taped seams and welded seams.
Critically tapes seams
This means that only portions of the seams or certain seams in the product are sealed, usually in the area most prone to leaks. Generally speaking, this is the lowest form of seal sealing because it is the least comprehensive and, thus, the least effective.
Fully taped seams
If any garment or product has “fully taped seams,” it means that every seam on it is – as the name suggests – sealed with tapes. As you might expect, this is the most effective form of seam sealing.
Welded seams
These are seams that are “welded” together by essentially melting the two pieces of fabric to create a tight, waterproof bond. The main benefit of welded seams is that the bond is often stronger than the original fabric and – unlike tape – the weld doesn’t require reapplication.
Seam taping: how it’s done
- Manufacturers apply thermoplastic tape to the seams using heat and pressure
- The heat melts the tape over the join, effectively providing a waterproof shield where the fabrics meet
- It's possible to do this yourself with a roll of waterproof seam tape
During the production process, manufacturers tape the seams on products by applying thermoplastic tape to the seam with heat and pressure. The application of heat effectively melts the tape over the join where the two pieces of fabric are sewn together to create a waterproof seal.
It is possible to do a DIY job on your waterproof gear’s seams if they start leaking. All you have to do is pick up a roll of waterproof seam tape, apply this to the leaky seam, and then replicate the factory sealing process by applying heat with the tip of a medium-hot iron. Alternatively, you can use liquid-based sealants like the Gear Aid Seam Grip+ SIL.
