Why Your Wetsuit Stopped Keeping You Warm
A wetsuit gets cold for four reasons and only one of them means you need a new suit. How to work out which one you have.
The Wetsuit Repair Shack·5 min read
The bench · Ocean Grove
The suit looks fine. No obvious holes, no split seams, nothing hanging off it. But you are getting out after forty minutes shivering, and last winter you did two hours in the same thing.
Something has changed. Here is how to find out what, because three of the four causes are fixable and only one of them means you need to buy a suit.
First, understand what keeps you warm
A wetsuit does not work by keeping water out. It works two ways.
The foam holds millions of tiny gas filled cells, and gas conducts heat far more slowly than water does. That is your insulation, and it is why thickness matters.
The fit does the rest. A thin layer of water sits between you and the suit, your body heats it, and it stays put. That only works if the water stays put. Any pathway that lets warm water out and cold water in destroys the effect no matter how thick the neoprene is.
So a cold suit is either a foam problem or a flushing problem.
Cause 1: the foam has compressed
This is the one that ends a suit.
Neoprene cells collapse over time under pressure, stretching, sun and repeated soaking. The suit looks the same but the gas has gone out of it. A compressed 4/3 performs like a 2mm.
How to check it: pinch a section of the chest or back between finger and thumb, squeeze firmly, then release. Good foam springs back immediately and feels springy through the squeeze. Tired foam feels thin and papery, and takes a beat to recover. Compare an area you never sit on, like the upper back, against the lower back and seat, which compress first.
Also hold the suit up to the light. Thin, translucent patches are foam that has given up.
Verdict: if the whole torso feels flat, the suit is finished. No repair adds warmth back. If only the seat and lower back have gone and the torso is sound, you have a summer suit and a spare.
Cause 2: the neck seal has stretched
The single most common cause of a suddenly cold suit, and the cheapest to fix.
Neck seals stretch. They get pulled over your head hundreds of times, and eventually the neoprene loses its grip on your skin. Every duck dive then pushes a column of cold water straight down your chest and out through the legs. You are effectively flushing the whole suit on every wave.
How to check it: put the suit on and look in a mirror. If you can slip two fingers flat between the seal and your neck without stretching anything, it is loose. Also think about where you feel cold first. Neck flush announces itself as a cold chest and cold thighs, in that order.
Verdict: fixable. Neck seals can be taken in or replaced, and it transforms a suit.
Cause 3: the zip or its baffle has failed
A back zip suit relies on a neoprene baffle behind the zip to stop water pouring through the teeth. Chest zip suits rely on the entry panel seal.
Baffles tear, come unstitched at the edges, or lose their elastic. The zip itself can also spread under load, with the teeth separating behind the slider while it still looks closed.
How to check it: lay the suit flat, zip closed, and look at the inside of the zip line. Any gap in the baffle, any lifted stitching, any daylight through the teeth is your leak. Then run a finger up the closed zip from the outside and see if it parts.
Verdict: fixable. Baffles get replaced, zips get replaced. Costs a fraction of a new suit.
Cause 4: seams have opened up
Seams fail progressively rather than all at once. A blindstitched seam can lose its tape or its liquid seal along a run without the panels separating, and you will not see it from the outside.
How to check it: turn the suit inside out in good light and go along every seam with your eyes and a fingertip. Look for lifted tape, cracked liquid seal, loose thread and any point where you can see through the stitch line. Ankles, wrists, underarms and the crotch go first.
The old trick still works. Fill the suit with water in the yard, hold the arms up, and watch where it weeps.
Verdict: fixable, and often the best value repair there is. A rebuilt seam is frequently stronger than the original.
The quick diagnostic
| Where you feel cold | Most likely cause |
|---|---|
| Chest and thighs, immediately after a duck dive | Neck seal stretched |
| Down the spine and lower back | Zip baffle or zip teeth |
| Localised cold spot in one place | Seam failure or a hole nearby |
| Uniformly cold everywhere, from the start | Foam compression |
Uniform cold from the moment you paddle out is the bad one. Cold that arrives after a wave is a flushing problem, and flushing problems are repairs.
Before you replace it
Most suits that get retired for being cold are not worn out. They have one failed component on an otherwise sound piece of gear, and the owner has no way of telling the difference from the beach.
Bring it in, or post it, and we will pinch the foam, pressure check the seams and tell you which of the four you have. If the answer is that the foam is gone, we will say so and you will not pay us anything to find out.
