My Thermarest Neoair Venture (very comfortable but cold) has an L shaped tear in it. 5cm by 3cm.
I didn't tear it! It happened by itself!

Is it repairable?

The surface isn't too clean.

Yes, I bought a replacement. Thermarest Xtherm nxt Max Long £174.50. I'm still

Worth contacting Thermorest / Cascade designs as they have a repair service plus their mats have a lifetime warranty. Failing that they'll give good advice on home repairs.

I only buy Thermarest - because of their warranty. Which I have used about 3 times.

Just unsure if a long tear is repairable and by me.

Exped do the same - I ripped a 3" slit on a root on a 4 year old well used mat. Posted it off and they did a really solid repair and posted it back all FOC.

3" so yours is bigger than mine

But good news. Just what I wanted to hear. Will get it fixed then.

On a root too!