Repairing Thermarest

-- Last Updated: Jan-15-15 10:23 AM EST --

I never head out on a paddling or backpacking overnighter without a thermarest. However, it seems like a given that at some point, I end up sleeping on flattened pad, not much different from sleeping on the ground. I think I am on my fifth one--currently using the NeoAir. I am happy with it, but it is so air-mattress like that I can't believe it won't pick up a puncture and leave me flat again, but I digress.

I got the NeoAir last summer when my Pro Plus left me flat on the rocky ground at Flaming Gorge. I believe the Pro Plus is currently sold as the ProLite Plus. I've finally got around to taking the Pro Plus into the tub and locating the pin-hole leak, which is right on the side seam, a tough place to patch. I may try smearing a bit of aquaseal over the leak and seeing if it holds.

However, I"m wondering what's the point. All the other thermarests I have had developed leaks along the seams, too. Is this just something that happens to these mats after years of use? Do you think it is worth trying to patch, or will I just end up flat on the ground again? What's the best way to patch seam leaks?


Also consider Seamgrip, similar but
more flexible and better able to penetrate or wick into fabric.

Our Thermarests have developed leaks along the inner fold lines, not on the edge seams. I sometimes think about not folding them tight, but more loosely, and using them in the canoes like added flotation. It is almost certainly the folding tight that created the leaks we have experienced.

I’ve had good luck with Thermarest…

– Last Updated: Jan-15-15 11:05 AM EST –

They're pretty easy to fix as well, with the flat surfaces making it easy to locate leaks. If it's just one pin hole leak I wouldn't worry, when you get multiple pin holes that is an indication of delaminating materials and it should be replaced under warranty. Try to store it loose with the valve open. I think a little seam seal will do the trick.
I've had terrible luck with Big Agnes pads delaminating on me, have probably spent close to three weeks sleeping on the ground because of three separate pads failing miserably. The baffles make it really difficult to locate the leaks, and delaminating material makes it impossible to repair. Fix three pin holes and five appear, repair five and next time there's seven. I will never purchase anything Big Agnes again.
I think as a lot of this gear gets lighter it's lifespan is also shortened. Kind of sucks considering the price. But I would like to think a well cared for mat should last many years.

care and warranty for Thermarest
after 25 years of using Thermarest mats I have a few opinions.

The original style (self inflating foam) are by far more resilient than the Neo Air ones. Not all Neo Air are the same; the thinner/lighter ones are rather easy to puncture. I had 4 Neo Air (first generation) replaced under warranty as they started to delaminate (became “pregnant”).

At every warranty claim I was asked if I left the mat inflated in a hot tent/car during the day. I know NOT to do that as hot air expands and would rupture a mat, no matter what style. Apparently Cascade Designs (maker of Thermarest) can tell if that occurred and will NOT warranty!

For repairing I use with most success Seam Grip. The downside: it take a few hours to cure, a bit of a pain if field repairing. Finding pinholes can be a real drag: submersing in water or wetting with soapy water is my way to find those.

After all this, I still think that is nothing better out there. I have tried Exped and other brands. Most delaminated very soon. Some manufacturers did not honor the warranty. Bottom line: I take care of my mats and I DO NOT place them directly on the ground that is rough and has pine needles. Smooth rock is OK. As for the Neo Air ultralight version I now use it only for super light backpacking outings. For kayaking I purchased a thicker (and slightly heavier) version of Neo Air (green in color) that has a sturdier fabric.

Get in touch with Cascade Designs
I had a seam go on an old (~15 yrs at the time) Thermarest. I asked about a repair process through their customer service page. They told me to pack it up & send it back. I did & not too much later it showed up again fixed. I was impressed given the age of the product.In the mean time I picked up a pro-lite. It packs smaller & so far seems to provide better insulation and is more comfortable even though it packs 1/2 the size.

I have been using therm a rest pads
for years and years. Never had a problem. Well, almost never. One time my partner cut it with a knife while making dinner in a necessity site while we were wind bound. Other than that I have had no leaks. One thing I do that might make a difference is to store my pads inflated with the valve open under my bed. They are never folded or rolled except when I am on a trip.

Stored rolled up
Maybe I’m the culprit that makes my thermarest leak. I mostly stored them rolled up.

For a while i tested leaving the pads unrolled until I was on a trip. I thought they might more easily reinflate. My judgement was I had to blow them up about the same regardless of how I stored them, so I just stored them rolled up.

I think I treat the thermarests with care. I try to because they are the difference between comfort and cold hard ground! So maybe it was because I stored them rolled up. Still, shouldn’t thermarest expect people are going to store them rolled up? I seem to remember they were sold with a bag and you can’t get the pad in the bag unless it is well rolled up.

I had a Big Agnes for a short period (before I returned it and got another thermarest).


Not going to point fingers
but you decide

We had two thermarests from the seventies or eighties.

Still after all those years no leak

We stored em loose valves open.

Of course it comes with a bag…chuckle. You dont want one of those flapping around loose in your boat.

I also think that storing flat with open
valve maximizes the life of the foam inside the mattress. If you store it compressed all the time I think the foam may get permanently compressed and lose the ability to self inflate over the years so you end up having to blow in the valve a LOT more. This happened to me with my first therm a rest and since I started storing flat with open valve I have not had that problem.

My experience
I have fixed 2 leaking thermarests, both belonging to the same friend. They both leaked at the margin of the valve base. This was caused by his opening and closing the valves with one hand causing the whole valve to twist. I used the stuff that came with them which worked well, but they quickly did the same thing and they leaked again. There is a lesson here. I give up.


mine haven’t leaked
I have four dating back to the 1970s as well. They have occasionally spent a few days rolled up in their sacks after I got back from a trip and was too lazy to unload everything right away, but generally I store them flat with the valves open.

Old Thermarests

– Last Updated: Jan-16-15 7:36 PM EST –

I have a decades old Thermarest that works perfectly well. I store it INFLATED with valves OPEN until it takes a trip. Nice and comfy to use if plenty of room to pack it and no worries about weight, however; I switched to Exped for smaller size and a little more comfort.

Exped has a good warranty, which I've had to utilize twice. First one leaked only after about 10 years and it's replacement developed leak around the valve after a year. Nice folks to deal with, but I have to admit my '80's vintage Thermarests were "Bomb proof." And they spent a lot of hours OUTSIDE on rocky Canadian Shield during that time.

Bought one of those Neo Air's for my wife the first year they came out and loved the nice, light packability. BUT, worried about durability because they felt a little too light? (Plus, it sounded like she was rolling around on a noisy balloon (LOL)! Sold it after about one year.

As for SEAM leaks, I wouldn't trust any "Patch" to work. Especially if I'm not an "Ultralight" person. As "Murphy's Law" goes, it will probably prevail at the worst possible time?

I don’t know about seam leaks but

– Last Updated: Jan-17-15 9:56 AM EST –

in the incident I describe above my therm a rest ended up with a 1/2 inch slice in the middle of the body of the pad (not seam) and I repaired it with a therm a rest repair patch and it is very solid. I trust the repair completely.